Documents published in 2018 : Scipedia

Les funcions de regulació i supervisió del Banc d’Espanya: el seu paper en la crisi bancaria
A. Todó

3r Congrés d'Economia i Empresa de Catalunya - Full papers.

Abstract
El paper analitzarà les causes de l'última gran crisi bancaria a Espanya, que s'inicia l'any 2007 (encara no tancada del tot) i que ha suposat la desaparició de 38 entitats financeres, passant de 50 a 12. El cost d'aquesta crisi ha estat de milers de milions de recursos públics destinats al rescat bancari i també la pèrdua de milions de llocs de treball. Analitzarem quin va ser el paper del Banc d'Espanya en la previsió, o no, de la crisi, quins mecanismes reguladors i de supervisió van fallar i com es va acabar gestionant aquesta crisi bancaria un cop es va veure, l'any 2011, que la crisi econòmica tindria forma de W. Finalment, es presentaran unes breus reflexions de caràcter general sobre com millorar els aspectes reguladors i supervisors, ara ja en mans del Banc Central Europeu.
Abstract
El paper analitzarà les causes de l'última gran crisi bancaria a Espanya, que s'inicia l'any 2007 (encara no tancada del tot) i que ha suposat [...]
- 39
- read
Límites y posibles efectos de la fiscalidad ambiental
A. Díaz Álvarez

3r Congrés d'Economia i Empresa de Catalunya - Abstracts.

Abstract
Si bien la fiscalidad ambiental durante mucho tiempo no consiguió dejar de ser un complemento de otros tributos en los sistemas fiscales de los diferentes países, la crisis económica alteró esta situación de forma notable, básicamente por dos razones: por su capacidad recaudatoria y por los beneficios ambientales que pueden derivarse de la aplicación de estos instrumentos. Aunque la función recaudatoria sea en muchos casos prioritaria, es preciso tener en cuenta que en el caso de la fiscalidad ambiental no puede ser éste el principio rector, sino que debería estar diseñada de tal modo que cumpliera con los principios siguientes: Eficacia ambiental: el principal objetivo de los impuestos ambientales debe ser la corrección del problema ambiental considerado. Eficiencia económica: el impuesto deberá lograr internalizar la externalidad ambiental, siendo capaz además de discriminar entre contaminadores en función de sus costes de reducción. Viabilidad práctica: los impuestos deben estar diseñados para poder ser aplicados en el mundo real. Incidencia distributiva: la carga fiscal debe distribuirse entre los distintos agentes de los costes que generan, teniendo en cuenta, por una parte, la posible traslación de la carga entre los agentes, y por otra el cumplimiento del principio “quien contamina paga”. A partir de lo anterior, analizaremos cuáles son los límites de la fiscalidad ambiental y hasta qué punto la aplicación en la práctica de medidas fiscales ambientales ha seguido o no los principios mencionados anteriormente, centrándonos en los requisitos que las políticas ambientales de la Unión Europea señalan que deben cumplir: No afectar a la competitividad No incrementar la carga fiscal, sino redistribuirla Tener como objetivo básico el cambio de conductas y no la recaudación en sí misma No suponer un obstáculo o un factor para la instalación de empresas en función del territorio
Abstract
Si bien la fiscalidad ambiental durante mucho tiempo no consiguió dejar de ser un complemento de otros tributos en los sistemas fiscales de los diferentes países, [...]
- 13
- 1/5
- read
La formació de postgrau al futur: perfils professionals i directius
M. ESPINOSA SAENZ

3r Congrés d'Economia i Empresa de Catalunya - Abstracts.

Abstract
Si acceptem que algunes de les característiques/perfils professionals en un futur pròxim poden focalitzar-se en: 1) La intel·ligència social, entesa com a l’ús d’informació social per promoure la cooperació, la capacitat per relacionar-se amb els altres de manera efectiva i la capacitat per identificar les relacions existents entre les persones. :2) La col·laboració virtual i transcultural. La capacitat per treballar de forma productiva mitjançant l’ús de diferents eines tecnològiques com a membre de grups virtuals formats per persones de geografies, ètnies, religions, gèneres i generacions diferents. 3) El pensament digital considerat com la capacitat per traduir enormes quantitats de dades en conceptes abstractes i comprendre la seva lògica. 4) La transdisciplinarietat com a capacitat adaptativa i coherent. 5) La reflexió ètica. Sense oblidar la competència creativa que, sense ser una nova competència, resulta imprescindible. Cal situar aquestes capacitats en el marc de la Quarta Revolució Industrial que, entre d’altres aspectes, ens col·loca davant de la intel·ligència artificial, de la robòtica... però també davant de l’impacte i les oportunitats de les tecnologies per donar resposta als reptes del medi ambient, l’agricultura, l’energia, la sostenibilitat... i tot dinamitzat i potenciat per les xarxes. Com hauria de ser la formació o educació? Sens dubte, inspiradora i, alhora, un estímul per innovar (nous negocis per satisfer necessitats en nous entorns), és a dir, per canviar les regles. L’avaluació de la formació, entesa com la diferència entre les expectatives i la realitat, serà un element clau en el futur de la formació d’executive education. I és a partir d’aquest punt que podríem plantejar algunes qüestions o interrogants: Com podem adaptar la nostra estratègia formativa al nou marc i en línia amb els perfils definits? Què necessitaran les nostres empreses i els nostres directius? Cal repensar totes les metodologies que utilitzem ara? Quin rol pot tenir la gestió per projectes en entorns digitals i cooperatius? Coneixent, per mitjà de diferents anàlisis existents, que hi ha un gap entre el coneixement/aplicabilitat i la percepció dels directius en el procés de digitalització present, i entenent la digitalització no com un conjunt d’instruments, sinó com una estratègia integral per repensar el conjunt de les nostres organitzacions, quines conclusions i experiències podem deduir del rol de la digitalització en la formació i en el conjunt de les organitzacions? A què ens referim quan parlem de la gestió de la diversitat en un sentit ampli? Com podrem compatibilitzar aquesta formació en l’espai/temps dels directius a nivell global? Com percebem cadascun de nosaltres la globalització? Quins elements podem identificar com a claus per gestionar la nostra direcció d’allò global? Com ens podem conscienciar que l’element més significatiu per als directius seran les persones amb les quals hauran de treballar, persones que, al llarg de la seva vida professional, hauran de reinventar-se en diferents ocasions?
Abstract
Si acceptem que algunes de les característiques/perfils professionals en un futur pròxim poden focalitzar-se en: 1) La intel·ligència social, [...]
- 5
- read
El edificio nZEB, el nuevo modelo arquitectónico que consuma cero: la experiencia de Picharchitects
M. Manca

3r Congrés d'Economia i Empresa de Catalunya - Abstracts.

Abstract
Este trabajo se basa en el conocimiento obtenido a partir del análisis y modelización de diversos edificios realizados, a lo largo de los años, por Picharchitects, empresa líder de la arquitectura sostenible en España. Las conclusiones muestran como la propia arquitectura, antes que la maquinaria añadida, es el vector principal en la obtención de edificios Nzeb y un parámetro determinante para la obtención de un modelo constructivo coherente en términos de calidad, coste y beneficio económico, en el contexto actual donde el sector de la edificación es responsable del 40% del consumo global de energía.
Abstract
Este trabajo se basa en el conocimiento obtenido a partir del análisis y modelización de diversos edificios realizados, a lo largo de los años, por [...]
- 19
- read
Tendències en mercats geogràfics des de la perspectiva de la implantació de les empreses
X. Mendoza Mayordomo

3r Congrés d'Economia i Empresa de Catalunya - Abstracts.

Abstract
El propòsit de la contribució és fer una aproximació a quines seran les tendències de localització geogràfica de les implantacions internacionals de les empreses catalanes en un mig termini. Altrament dit, quins seran els mercats geogràfics que, per exigència o per oportunitat, les empreses hauran de considerar per obrir les seves filials? La resposta a aquesta pregunta s’articula en quatre apartats. El punt de partida és conèixer, segons les darreres dades disponibles, en quins països i regions internacionals tenen filials les empreses amb seu social a Catalunya, tot distingint els patrons de localització de les empreses propietat d’inversors nacionals dels d’aquelles que són filials de multinacionals estrangeres. En el segon apartat s’analitza, d’una banda, l’evolució recent dels fluxos i dels estocs d’inversió directa als principals països i regions internacionals i, de l’altra, l’evolució recent de la xifra de negoci, nombre d’empleats, marge sobre vendes i rendibilitat de les filials a l’exterior de les empreses catalanes, en ambdós casos en relació amb els principals països i regions internacionals. Com és conegut, els beneficis empresarials són un dels millors predictors d’inversions futures. El tercer apartat aporta una visió de les tendències internacionals pel que fa a la localització geogràfica de la inversió directa per part de les empreses residents a economies avançades, que es complementa amb les previsions que fan alguns organismes internacionals i centres d’estudis de reconegut prestigi sobre quins països mostren un major potencial de creixement a mitjà-llarg termini. El quart i darrer apartat sintetitza les principals conclusions de les anàlisis anteriors en termes de les tendències previsibles (i desitjables) en un mig termini de localització geogràfica de les implantacions internacionals de les empreses catalanes.
Abstract
El propòsit de la contribució és fer una aproximació a quines seran les tendències de localització geogràfica de les implantacions [...]
- 8
- read
Las relaciones entre la universidad y la empresa como factor de competitividad
J. Bonet

3r Congrés d'Economia i Empresa de Catalunya - Abstracts.

Abstract
Desde la perspectiva empresarial, el activo más importante es su capital humano. La disposición de recursos humanos abundantes y con las capacitaciones y habilidades precisas para el desarrollo de las tareas asignadas es determinante para la innovación, la asimilación y aprovechamiento tecnológico, la productividad y la competitividad de las empresas. Y, en definitiva, para su sostenibilidad y progreso. Desde la óptica empresarial, en la actualidad existe un desajuste entre la enseñanza que se imparte en los distintos niveles educativos y las habilidades y conocimientos demandados en el mercado laboral. Al tiempo, una de las causas del reducido tamaño medio del tejido empresarial es la falta de capital humano, especialmente en determinados ámbitos de gestión y en los cuadros de dirección de las empresas. Con mayor concreción, para las empresas, la Universidad, presenta buenos resultados globales en la generación de conocimientos, pero adolece de diversas debilidades, como la reducida vinculación con la empresa, la gestión burocratizada, la escasa transferencia de conocimientos del sistema de I+D+i a las empresas, la masificación en determinadas titulaciones, la lenta adaptación a las nuevas demandas o el insuficiente estímulo del espíritu emprendedor. El resultado se resume en un dato revelador: apenas un tercio de las compañías españolas ha colaborado con las Universidades en su actividad productiva. El análisis planteado trata de profundizar en la identificación de las necesidades del tejido empresarial en su relación con el mundo universitario, ofreciendo asimismo una visión sobre las oportunidades existentes para transitar hacia una mayor interrelación en aras del interés general.
Abstract
Desde la perspectiva empresarial, el activo más importante es su capital humano. La disposición de recursos humanos abundantes y con las capacitaciones y habilidades [...]
- 5
- read
Education choices in Catalonia
A. Kucel, M. Vilalta-Bufi

3r Congrés d'Economia i Empresa de Catalunya - Full papers.

Abstract
We study whether parental education affects the choice of tertiary education in Spain. We analyze two qualitative characteristics of the university studies: the length of the program and its academic prestige. We identify for which individuals parental background matters the most. For the choice of a long program, parental background changes the most likely outcome for students with low grades in the academic track and those with excellent grades in the vocational track. Regarding the prestige of the program, parental background matters the most for the worse performing boys and the girls with rather good grades in the academic track.
Abstract
We study whether parental education affects the choice of tertiary education in Spain. We analyze two qualitative characteristics of the university studies: the length of [...]
- 19
- read
Materias primas minerales críticas: una visión en el contexto de los recursos geológicos globales y de Cataluña
J. Proenza, J. Melgarejo

3r Congrés d'Economia i Empresa de Catalunya - Abstracts.

Abstract
A la industria minera le gusta decir “si no se cultiva, habrá que extraerlo de una mina”. Los recursos minerales son imprescindibles para el desarrollo de la sociedad, y muy particularmente los recursos minerales a partir de los cuales se extraen los denominados metales de alta tecnología (“high-tech metals”). Estos metales son componentes esenciales en diversas aplicaciones técnicas de alta gama, tales como las denominadas tecnologías verdes asociadas a las energías renovable, la reducción de gases de efecto invernadero y la eficiencia energética. Con la creciente importancia de las nuevas tecnologías y la revolución energética, han surgido preguntas sobre la disponibilidad futura de recursos de materias primas minerales, particularmente las denominadas “críticas”. La “criticidad" es una estimación del riesgo de suministro de materias primas, la escasez que puede poner en peligro el funcionamiento de una sociedad. El reciclaje de los recursos existentes, incluso si se pudiera conseguir que fuera 100% eficiente, no puede satisfacer todas las necesidades. Indiscutiblemente, la denominada economía circular es una parte de la solución a la “molestia” de la minería y sus impactos ambientales asociados, pero no es la solución definitiva debido al aumento de la población y la mejora del nivel de vida global. Lo más probable es que la demanda de minerales continúe aumentando en el futuro. Las reservas minerales globales son, en principio, adecuadas, pero la producción está limitada y/o dominada por algunos países. En esta contribución presentamos una visión sobre las materias primas minerales críticas (ej: metales del grupo del platino, tierras raras, Nb, Co, Ge, etc.) desde una perspectiva de los recursos geológicos a nivel de global y de Cataluña. Aunque se tiene la idea de que Cataluña no es un país de tradición minera, lo cierto es que la mineria en Cataluña es de las más antiguas y continuadas en el mundo. En cuanto a potencial, cuenta con recursos conocidos propios pero jamás evaluados para Au, PGE, Ag, F, Ba, Sc, REE, Rb y Cs. Además, hay suficiente know-how para poder apoyar inversión en minerales críticos en terceros países.
Abstract
A la industria minera le gusta decir “si no se cultiva, habrá que extraerlo de una mina”. Los recursos minerales son imprescindibles para el desarrollo [...]
- 33
- read
Una alternativa numérica en la solución de un sistema que modela la producción de biogás
M. Machado

Revista Mexicana de Métodos Numéricos (2018). Vol. 2

Abstract
We study a simplified model of the Anaerobic Digestion Model Number One (ADM1) that represents Anaerobic Digestion for the biogas production and wastewater treatment. This system is modeled by systems of nonlinear differential equations. First, we implemented the Dimensional Analysis to obtain an equivalent model with non-dimensional variables and parameters. Then, numerical solutions are solved both the initial model and the non-dimensional model, and we comparative graph between their corresponding numerical solutions. where we see the advantages of working with the non-dimensional model with respect to the original model.
Abstract
We study a simplified model of the Anaerobic Digestion Model Number One (ADM1) that represents Anaerobic Digestion for the biogas production and wastewater treatment. This [...]
- 112
- read
The mapping between Chinese medicine and signaling molecules
S. LIU, Y. Liu

Traditional Chinese Medicine and Molecular Signaling (2018).

Abstract
Knowledge of signal transduction pathways and their corresponding signaling molecules is critical in evaluating potential therapeutic targets. Traditional Chinese Medicine (TCM) used Yang and Yin to describe the physiological processes in human body, but its scientific basis is unknown. According to “Yellow Emperor’s Inner Canon” (YEIC)―the fundamental doctrinal source for TCM―there are five elements of Yang-Yin, each pertaining to particular physiological functions. Their interaction and relationship determine the physiological conditions of human being. In this work, iterative selection method was used to correlate YangYin-Qi with signal molecules. It is revealed that the signal transduction pathways are identical to the dialectical relationships of Yang-Yin-Qi(s). With the direct mapping between Yang-YinQi(s) and signaling molecules, the signal transduction pathways are consistent with TCM therapeutic strategies too. In addition, it is demonstrated that the Chinese herbal medicine regulates signal transductions. With the correlation between Yang―Yin(s) and signal transduction pathways, it is evident that the modern medicine and TCM identified the same pathogenesis of diseases, such as hematuria, constipation, hemorrhoidal disease, nocturnal enuresis, frequent urination, gall stone, acute cholecystitis and hypertension, etc; with highly similar treatment strategy, albeit using different terminologies.
Abstract
Knowledge of signal transduction pathways and their corresponding signaling molecules is critical in evaluating potential therapeutic targets. Traditional Chinese Medicine [...]
- 28
- read
Qualificació, ocupació i model productiu (2002-2017)
M. Arcarons

3r Congrés d'Economia i Empresa de Catalunya - Abstracts.

Abstract
La primera part d’aquest treball descriu entre 2002 i 2017, a partir de l’EPA, l’evolució de la composició de la població ocupada per nivells de formació assolida. Això permet observar el comportament de l’ocupació en el tram final del cicle expansiu que finalitza el 2008, al llarg de la doble recessió entre 2008 i 2013 i en els posteriors anys de reactivació fins al 3r trimestre de 2017. Es posa en relleu la diferent dinàmica de l’ocupació en els tres nivells (baix, mitjà i alt) d’estudis. En la segona part, es formulen diferents descripcions de la dinàmica de l’ocupació pel nivell de qualificació (skill level) de les ocupacions (llocs de treball ocupats). L’objectiu és comparar l’evolució del nivell de formació de les persones ocupades amb la del nivell competencial requerit per les ocupacions que exerciten. Per a això, s’assagen dues agrupacions dels grans grups de la CIUO-08 per estratificar l’ocupació en tres nivells competencials. Primer, s’assaja una extrapolació del criteri que l’OIT aplica en la CIUO-08 i s’agrupen, amb el mateix criteri, els nivells competencials de les ocupacions i els nivells d’estudis dels ocupats. Les possibles objeccions a aquest procediment porten a aplicar un procediment alternatiu, seguint el sistema d’indicadors publicat el 2015 per l’Observatori d’Empresa i Ocupació. Les comparacions entre la distribució de la població ocupada per nivells educatius i per nivell de qualificació de l’ocupació, realitzades amb un i altre mètode, no desmenteixen una situació de notable desajust vertical en el mercat laboral de Catalunya. Finalment es formulen conclusions i se sosté la conveniència d’un indicador de major precisió per avaluar l’evolució de la concordança entre el nivell formatiu de les persones i el nivell competencial de les ocupacions, sense que això impliqui l’acceptació d’una noció adequacionista.
Abstract
La primera part d’aquest treball descriu entre 2002 i 2017, a partir de l’EPA, l’evolució de la composició de la població ocupada per [...]
- 51
- read
La configuració de les autoritats de competència. Un model per a la regulació d’organismes independents i per a la reforma de l’administració pública
A. soria, X. Puig, M. Realp

3r Congrés d'Economia i Empresa de Catalunya - Abstracts.

Abstract
La política de competència contribueix decisivament a un funcionament eficient i equitatiu de l'economia. I és que, només en un marc de competència es pot garantir la millor assignació possible de recursos que maximitzi la generació de béns i serveis. A més, la política de competència té també un interessant component equitatiu en la mesura que actua com a mecanisme que vetlla per l'absència de barreres injustificades a l'entrada al mercat - facilitant doncs un marc igualitari en termes d'oportunitats - i pel fet que contribueix a garantir que els grans operadors competeixin entre sí de tal manera que se'n vegin beneficiats els consumidors i usuaris (en preus, qualitat i innovació). Els mecanismes a disposició de les autoritats de competència són rellevants. En relació a les administracions públiques les poden sancionar quan actuen com operadors, criticar la regulació que emeten i fins i tot impugnar-la davant dels tribunals. Les temptacions per tal que una autoritat de competència no sigui veritablement independent són significatives. Davant d’aquest risc, el document se centrarà en desenvolupar un condicionant necessari per tal que el seu funcionament sigui òptim: la seva independència. S'exposarà com es pot assegurar que les autoritats de competència gaudeixin de la independència que la seva actuació exigeix a través de l'anàlisi d'elements com: la forma jurídica que adopta la institució, la gestió del seu propi personal i garanties d'estabilitat del mateix, la gestió econòmica del pressupost que se li assigna i com determinar-lo, el nomenament i les causes de remoció dels seus alts càrrecs així com la rendició de comptes de la institució. L'interès del document va més enllà de les autoritats de competència. Les seves conclusions poden ser extrapolables a organismes reguladors i, tot plegat, pot constituir la llavor d'una nova manera de funcionar de les administracions públiques.
Abstract
La política de competència contribueix decisivament a un funcionament eficient i equitatiu de l'economia. I és que, només en un marc de competència [...]
- 32
- read
La qualitat del treball i la seva relació amb la sostenibilitat i futur del sistema de benestar i pensions
J. Ginesta

3r Congrés d'Economia i Empresa de Catalunya - Abstracts.

Abstract
Som en una fase expansiva del mercat de treball i al bell mig de la recuperació de llocs de treball que havíem arribat a tenir. Recuperació que es constata, tant en la reducció del nombre de persones aturades registrades i les que no, com també en la millora de les taxes d’ocupació i d’activitat. No obstant, s’evidencia, i és percebut per la ciutadania, que aquesta recuperació avança en perjudici de la qualitat del treball i dels drets de les persones treballadores. Es significa especialment en l’eix de la temporalitat i la parcialitat, i s’observa en les taxes, en les estadístiques de contractació, i també, en l’estoc de persones en alta al règim general de la seguretat social. Aquesta recuperació intensa esdevé indefectiblement feble, pel que fa a la seva consistència en la lògica del mercat com en la sostenibilitat social del model, en el benentès que ha vingut acompanyada també per una contenció salarial, però alhora, una reducció d’ingressos de les persones pel propi efecte de l’increment de la temporalitat i la parcialitat. Esdevé clau pel futur de Catalunya que es trobi l’encaix entre la creació de treball sostenible i que aquest permeti projectes vitals dignes per les persones que el desenvolupen. Trencar la dicotomia de que no és possible crear treball amb drets i estable. Aquest encaix ha de venir de la millora de la productivitat, de la introducció de sistemes d’avaluació del rendiment o retiment de comptes, i en definitiva, per crear llocs de treball de valor afegit que permetin guanyar consciència de quin és el valor que aporta i com s’incrementa; la sostenibilitat d’un lloc de treball entesa com aquell que permet donar valor al compte de resultats de l’empresa i al projecte vital de la persona que l’executa. Però també esdevé clau que comencem a aprofundir en polítiques d’ocupació que més que ancorar a l’individu en un lloc de treball, permetin el seu apoderament i fortalesa en un mercat de treball dinàmic i amb ocupacions volàtils. També esdevé clau, en el marc d’unes societats amb grans reptes al voltant de l’envelliment, l’increment de la dependència i de l’esperança de vida, amb sistemes de protecció social amb taxes de retorn gestades en entorns socials i demogràfics diferents, que el treball pugui continuar sent el principal instrument de finançament directe i indirecte del benestar. Que es creï treball suficient per crear sistemes de redistribució de rendes que permetin sistemes impositius capaços de generar ingressos suficients, però alhora, treball que per la seva qualitat, assegurin que la generació de tributs i cotitzacions per càpita, permeti un adequat equilibri entre els actius necessaris per sostenir els passius existents.
Abstract
Som en una fase expansiva del mercat de treball i al bell mig de la recuperació de llocs de treball que havíem arribat a tenir. Recuperació que es constata, [...]
- 47
- read
La regulació de les tecnologies emergents
A. Roig

3r Congrés d'Economia i Empresa de Catalunya - Full papers.

Abstract
No sembla possible regular les noves tecnologies només amb regles o principis generals. Cada cop més es fa ús de Impact Assessment o anàlisi de riscos. Ara bé, no és possible pensar en una optimització final dels riscos, sinó en un procés cíclic de re-avaluació constant. La institucionalització d’aquesta mena de procés de co-regulació tot just comença: plataformes digitals informals adquireixen funcions co-reguladores, ignorades encara per les tècniques oficials de “Better Regulation” de la UE. Un alineament entre la regulació i la tecnologia podria beneficiar no només al legislador, més eficient i actualitzat, sinó també als usuaris i als actors.
Abstract
No sembla possible regular les noves tecnologies només amb regles o principis generals. Cada cop més es fa ús de Impact Assessment o anàlisi de [...]
- 20
- read
L’Agència Nacional d’Economia del Coneixement (ANEC). Un vehicle integral per a la innovació i transferència de tecnologia a Catalunya
M. Castelltort, R. Martínez, M. Mausbach

3r Congrés d'Economia i Empresa de Catalunya - Abstracts.

Abstract
És àmpliament reconegut el gap existent entre els excel·lents resultats generats pel sistema català de recerca i el desenvolupament de productes o serveis que impactin en la societat. Reforçar i integrar els processos i instruments de valorització o transferència tecnològica és quelcom prioritari en una economia amb projecció global i basada en el coneixement. Les limitacions del sistema actual són (1) la fragmentació de la inversió en transferència, (2) la reduïda retenció del talent en aquest àmbit, (3) l’existència de micro-portafolis, (4) el risc individualitzat, (5) el posicionament fragmentat davant del client i del finançament de proves de validació i (6) un marc legal que no accelera la transferència de coneixement al mercat. Per tal de superar els reptes anteriors es proposa la creació d’una Agencia Nacional d’Economia del Coneixement (ANEC), amb la missió de definir i implementar una única estratègia de transferència de coneixement per a tot el sistema de recerca i innovació de Catalunya. Els objectius principals d’aquesta estructura serien: crear sistemes d’atracció i retenció de professionals en transferència de coneixement, generar un portafoli integrat amb estratègies de desenvolupament de negoci en base als sectors prioritzats a Catalunya, optimitzar els processos interns i l’acceleració de projectes de valorització i prova de concepte, desenvolupar instruments de risc compartit i crear un marc legal que permeti millorar la competitivitat de la recerca i innovació catalanes. Les estructures actuals als centres proveïdors de coneixement estarien focalitzades en la identificació i generació de projectes de transferència i els professionals dels centres treballarien en coordinació amb l’ANEC per transferir la responsabilitat en el desenvolupament de negoci i comercialització dels projectes. En resum, l’ANEC constitueix un vehicle integral i inclusiu en la professionalització de la transferència de coneixement a Catalunya.
Abstract
És àmpliament reconegut el gap existent entre els excel·lents resultats generats pel sistema català de recerca i el desenvolupament de productes [...]
- 79
- read
Economia Circular a Catalunya
J. Tost

3r Congrés d'Economia i Empresa de Catalunya - Abstracts.

Abstract
La contribució d’una gestió eficient dels residus al foment de l’economia circular. Josep Maria Tost Director de l'Agència de Residus de Catalunya L'economia circular és un model econòmic i productiu que estableix que qualsevol residu és un recurs. Aplicant les seves bases, aconseguim: - Millorar els resultats econòmics reduint l'ús dels recursos - Identificar i crear noves oportunitats de creixement econòmic - Garantir la seguretat del subministrament de recursos essencials - Lluitar contra el canvi climàtic (un 3% del factor climàtic té a veure amb la gestió de residus) A Catalunya s’ha plantejat un horitzó del 60% de recollida selectiva per a 2020 i, tenint en compte que actualment s’està en el 38% de, cal avançar en les estratègies per millorar aquests resultats. Les administracions, les empreses i la societat en general són claus per tal d’assolir un circularitat dels residus com a recursos.
Abstract
La contribució d’una gestió eficient dels residus al foment de l’economia circular. Josep Maria Tost Director de l'Agència de Residus [...]
- 32
- read
Estimation of kinetic parameters in a chromatographic separation model via Bayesian inference
C. Oliveira, J. Junior, D. Knupp, A. Neto, A. Prieto-Moreno, O. Llanes-Santiago

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 26

Abstract
The modeling of adsorption processes appears quite frequently in the chemical industry, petrochemical plants and refineries, for example for separation and purification of mixtures in Simulated Moving Bed (SMB) units. In the mathematical formulation, the accurate determination of the model parameters is an important step for the design of chromatographic conditions for continuous separation in SMB processes. This work is aimed at the estimation of the model parameters in adsorption processes, using a chromatographic column for the separation of glucose and fructose. The Bayesian framework for inverse problems is investigated through the implementation of Markov Chain Monte Carlo methods (MCMC) and a critical comparison against the classical Maximum Likelihood approach, with the minimization of the objective function via two different stochastic techniques, namely the Particle Collision Algorithm (PCA), and the Particle Swarm Optimization (PSO) is performed. Different cases are presented in order to investigate the statistical significance of the estimates obtained, and perform comparisons between the solution via Bayesian inference and via the minimization of the objective function with the stochastic methods. The results demonstrate that the Bayesian approach employs less computational effort to achieve estimates with comparable statistical information.
Abstract
The modeling of adsorption processes appears quite frequently in the chemical industry, petrochemical plants and refineries, for example for separation and purification of [...]
- 320
- read
Use of the SVD method for the stability analysis of tensegrity structures
A. González, A. Luo

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 30

Abstract
In this paper, the application of the singular value decomposition SVD for the analysis of tensegrity structures is presented. For this purpose, the SVD method is described generally, without detailing the calculating method. Next, the equilibrium equations of tensegrity structures are defined. The solution to the homogeneous system of equilibrium of the tensegrity structures is developed using the SVD method, and the meaning of the values in the matrices is presented. The method is used for the solution of several structures, some of them widely studied and some new.
Abstract
In this paper, the application of the singular value decomposition SVD for the analysis of tensegrity structures is presented. For this purpose, the SVD method is described [...]
- 521
- 5/5
- read
Sobre los alcances del dominio de validez de los diagramas de Venn-Euler
C. Rodríguez

Collection of Articles on Mathematics (2017).

Abstract
En este trabajo se muestra de forma rigurosa que los métodos de diagramas de Venn sí son procedimientos formales de demostración de las fórmulas de conjuntos para ciertos subconjuntos, determinándose de forma exacta la familia de conjuntos que cumplen con esta condición. Cabe mencionar que en este trabajo solo se considera la teoría de conjuntos clásica que acepta la hipótesis del continuo, por lo que el dominio de validez de los diagramas de Venn que aquí se demuestra sólo es aplicable a los conjuntos considerados bajo este supuesto.
Abstract
En este trabajo se muestra de forma rigurosa que los métodos de diagramas de Venn sí son procedimientos formales de demostración de las fórmulas [...]
- 78
- read
Simulation of the two-dimensional flow of the initiation channel of the Itaipu hydroelectric power plant by the lattice Boltzmann method
J. Cargnelutti, V. Galina, E. Kaviski, L. Gramani, A. Lobeiro

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 25

Abstract
This paper analyzes the ability of the Lattice Boltzmann method (LBM) with multiple relaxation times (MRT) in the simulation of flow in practical engineering problems. The case study covered refers to the first section of the initiation channel, which is part of the piracema channel, located in the Itaipu Hydroelectric Power Plant. The initiation channel has submerged obstacles distributed from one margin to the other, in order to reduce water velocity and allow the piracema cycle to occur. The governing equations of flow are the shallow water equations, which will be solved through the LBM-MRT. The non-slip bounce-back scheme was used on walls and obstacles, constant discharge at the inlet and fixed depth at the outlet of the channel. Due to the characteristics of the problem to be simulated, a large eddy simulation (LES) technique was incorporated into the computational code, which allows to obtain results that are closer to the actual behavior of the flow. In addition, the stability of the simulation at all points of the mesh is evaluated for each step of time and, together with the property of the consistency of the LBM, the convergence of the solution is obtained. The simulation provides the depth, velocities in the x and y directions, and the magnitude of water vorticity.
Abstract
This paper analyzes the ability of the Lattice Boltzmann method (LBM) with multiple relaxation times (MRT) in the simulation of flow in practical engineering problems. The [...]
- 234
- read
Design of an inflatable, modular and portable footbridge
A. Rodríguez, E. Oñate, J. Marcipar

Monograph CIMNE (2017). M175

Abstract
Optimization of the use of resources and adaptability of the structures to their environment are new concerns in architecture and structural engineering. At the same time, ephemeral structures are gaining relevance in the market for their uses in maintenance and repair, organization of events, rescue and emergencies and temporary works. Inflatable structures satisfy two of the points aforementioned: they require small amounts of materials and are adequate for ephemeral structures, due to their low deflated volume and lightness. They are also adaptable in the sense that their overpressure determines their load carrying capacity. However, they are inadequate for environments where high external loads may be present. Tensairity appears as a solution to this problem, increasing the carrying capacity of inflatable structures without renouncing to their advantages. This technology adds two extra structural elements to inflatable beams, with greater strengths, in order to redistribute stresses along it. The inflatable element serves then to couple the two stiff elements and to avoid buckling. This work presents and explores design possibilities of Tensairity beams with special focus on their computational modelling. Then, research is carried out regarding modular Tensairity beams, thought as a solution for deployable footbridges. A prototype was built and tested in serviceability conditions to prove the fitness of the proposal to a commercial level.
Abstract
Optimization of the use of resources and adaptability of the structures to their environment are new concerns in architecture and structural engineering. At the same time, [...]
- 490
- read
Numerical analysis of railway ballast behaviour using the Discrete Element Method
J. Irazábal González, E. Oñate, F. Salazar

Monograph CIMNE (2017). M174

Abstract
The development of high-speed train lines has increased significantly during the last twenty-five years, leading to more demanding loads in railway infrastructures. Most of these infrastructures were constructed using railway ballast, which is a layer of granular material placed under the sleepers whose roles are: resisting to vertical and horizontal loads and facing climate action. Moreover, the Discrete Element Method was found to be an effective numerical method for the calculation of engineering problems involving granular materials. For these reasons, the main objective of the work is the development of a numerical modelling tool based on the Discrete Element Method which allows the users to understand better the mechanical behaviour of railway ballast. The first task was the review of the specifications that ballast material must meet. Then, the features of the available Discrete Elements code, called ''DEMPack'', were analysed. After those revisions, it was found that the code needed some improvement in order to reproduce correctly and efficiently the behaviour of railway ballast. The main deficiencies identified in the numerical code were related to the contact between discrete element particles and planar boundaries and to the geometrical representation of such a irregular material as ballast. Contact interactions between rigid boundaries and Discrete Elements are treated using a new methodology called the Double Hierarchy method. This new algorithm is based on characterising contacts between rigid parts (meshed with a Finite Element-like discretisation) and spherical Discrete Elements. The procedure is described in the course of the work. Moreover, the method validation and the assessment of its limitations are also displayed. The representation of irregular particles using the Discrete Element Method is a very challenging issue, leading to different geometrical approaches. In this work, a deep revision of those approaches was performed. Finally, the most appropriate methods were chosen: spheres with rolling friction and clusters of spheres. The main advantage of the use of spheres is their low computational cost, while clusters of spheres stand out for their geometrical versatility. Some improvements were developed for describing the movement of each kind of particles, specifically, the imposition of the rolling friction and the integration of the rotation of clusters of spheres. In the course of this work the way to fill volumes with particles (spheres or clusters) was also analysed. The aim is to control properly the initial granulometry and compactness of the samples used in the calculations. After checking the correctness of the numerical code with simplified benchmarks, some laboratory tests for evaluating railway ballast behaviour were computed. The aim was to calibrate the ballast material properties and validate the code for the representation of railway ballast. Once the material properties were calibrated, some examples of a real train passing through a railway ballast track were reproduced numerically. This calculations allowed to prove the possibilities of the implemented tool. This publication is a revised version of the text of the PhD Thesis “Numerical analysis of railway ballast behaviour using the Discrete Element Method” of Joaquín Irazábal, presented at the Technical University of Catalonia on October 6th 2017
Abstract
The development of high-speed train lines has increased significantly during the last twenty-five years, leading to more demanding loads in railway infrastructures. Most of [...]
- 508
- read
Approximation of the shallow water equations with higher order finite elements and variational multiscale methods
A. Villota, R. Codina

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 28

Abstract
In this article, we present approximations with finite elements of high order using stabilized variational multiscale methods to approximate the equations of motion of a fluid in shallow waters. We write these equations as a system of non-linear and transient convection-diffusion-reaction (CDR) equations and we perform our developments in this general framework. Variational multiscale methods (VMS) are based on the decomposition of the unknowns of the continuous problem in a resolved component in the finite element space and another component that cannot be captured by the finite element mesh, and that we call subscale. The subscale is approximated in terms of the finite element solution, obtaining a robust numerical scheme, which in particular allows one to use the same interpolation for all unknowns and the possibility to deal with convection dominated flows (we will not consider the possibility of dealing with shocks). The two VMS methodologies that we will consider are called algebraic subscales (ASGS) and orthogonal subscales (OSS).
Abstract
In this article, we present approximations with finite elements of high order using stabilized variational multiscale methods to approximate the equations of motion of a fluid [...]
- 220
- read
Another FEM: Rectangular element of 4 nodes
F. Martin Chica

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 29

Abstract
In both of the traditional FEM and the proposed methodology in this article, the compatibility equations are obtained from the same interpolation functions, so the elementary matrix that relates deformations in the nodes of the element with the displacements of that nodes are the same in both procedures. But, whereas in that one the PVW is applied to establish the Equivalent Nodal Forces to be used for the achievement of the equilibrium equations of all the nodes of the structure, in which these forces are obtained from the hypothesis that the stresses on all four sides of the elemental rectangle vary linearly along these sides and are thus to replace said stresses as statically equivalent, concentrated forces. Since the system of equations used in this procedure is given in all the unknowns of the problem explicitly, and it is possible to impose any kind of restriction on any of these unknowns, so that, in addition to the conditions of essential support to avoid movement as a solid rigid, conditions of equilibrium are imposed on every one of the elements that discretize the structure, which is not possible with the usual procedure that, therefore, must resign to be fulfilled in a way such a balance. The practical examples studied at the end show somewhat improved results with respect to the FEM usual procedure.
Abstract
In both of the traditional FEM and the proposed methodology in this article, the compatibility equations are obtained from the same interpolation functions, so the elementary [...]
- 237
- read
Improved procedure for determining the ductility of buildings under seismic loads
J. Vielma-Perez, M. Mulder

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 27

Abstract
Displacement ductility is a parameter that characterizes the seismic response of structures. Moreover, displacement ductility can be used in order to determine whether a structural design, performed according to a specific seismic code or not, may achieve the main goal of the seismic design: to develop energy dissipation in a stable manner. Determination of displacement ductility is not an easy task, because the structural response usually does not show a clear location of the points that define yield and ultimate displacements. In this paper, some of the main procedures for ductility displacement are revised and compared, and then improvements are performed to such procedures in order to compute the displacement ductility. A new procedure is then introduced, leading to determine the ultimate displacement using the seismic collapse threshold and the yield displacement, achieving the balance of dissipated energy. The procedure has been used to calculate displacement ductility of reinforced concrete framed buildings.
Abstract
Displacement ductility is a parameter that characterizes the seismic response of structures. Moreover, displacement ductility can be used in order to determine whether a structural [...]
- 297
- read
High-order CE/SE scheme for dam-break flow simulation
A. Rodrigues de Melo, L. Gramani, E. Kaviski

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 9

Abstract
This paper presents a new explicit scheme for the solution of shallow water equations in one and two space dimensions, developed from the space-time conservation element and solution element (CE/SE) method. The basis functions used are second-order Taylor expansions in time and space. This increase in the order of the approximation functions produces an increase in the number of unknowns in the scheme, therefore, besides the flow variables and their slopes, their second-order partial derivatives are also unknown in the present scheme. An iterative process for the calculation of the first and second order derivatives is formulated for problems with shocks and discontinuities. Computational experiments demonstrate third-order accuracy. The one-dimensional and two-dimensional dam-break problems presented validate the accuracy and robustness of this scheme.
Abstract
This paper presents a new explicit scheme for the solution of shallow water equations in one and two space dimensions, developed from the space-time conservation element and [...]
- 166
- 5/5
- read
A new mechanical structural damage feature index based on HHT
L. Hua, F. WANG, Z. Yue

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 23

Abstract
A new damage feature index is presented for the structural health monitoring based on Hilbert-Huang transform (HHT). The energy marginal spectrum of the dynamic signal is used to construct damage characteristic parameter, which can reflect the signal energy variation and benefit the structural damage detection. A sinusoidal wave with frequency change and a composite plate vibration experiment with pre-defined damage are designed to verify the effectiveness of characteristic parameter in damage detection. Results obtained from simulation and test show that the extracted non-model-based damage feature index is available and sensitive in damage detection of time-varying system.
Abstract
A new damage feature index is presented for the structural health monitoring based on Hilbert-Huang transform (HHT). The energy marginal spectrum of the dynamic signal is [...]
- 241
- read
Advanced computationally efficient modeling of RC structures nonlinear cyclic behavior
B. Alfarah, F. Almansa, S. Oller

Monograph CIMNE (2017). M173

Abstract
Under severe seismic excitation, structural behavior of buildings and other constructions is highly complex. It involves, among other issues, soil-structure interaction, large strains and displacements, damage, plasticity, and near-collapse behavior. Moreover, in reinforced concrete structures, there are several coupled degradation and failure modes: cracking, crushing and spalling of concrete, yielding and pull-out of tensioned reinforcement, yielding and buckling of compressed reinforcement. Furthermore, another circumstance makes the situation more alarming: given the increasing awareness and concern on the huge worldwide seismic risk, earthquake engineering has experienced in last years substantial advances. New design and analysis strategies have been proposed, leading to relevant developments. These developments rely on extensive testing and numerical simulation mainly based on oversimplified models referred in this work as structural component-based models, as a result of their moderate computational cost. Therefore, there is a strong need of verifying the reliability of the new developments by comparison with analyses performed using more advanced simulation tools and with experiments. This work is organized in two parts. First part presents an accurate model, while the second part deals with a more simplified model, although highly computational efficient.
Abstract
Under severe seismic excitation, structural behavior of buildings and other constructions is highly complex. It involves, among other issues, soil-structure interaction, large [...]
- 43
- read
Analytical solution proposal for fast numerical algorithm in special structured higher order differential equations
I. Derin, Y. Hames

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 21

Abstract
We suggest a practical method for obtaining the particular solution of non-homogeneous higher order linear differential equations with constant coefficients. The proposed method can be applied directly and simply to such problems. We revealed that is valid for the different type of problem by using sample solutions. This simple analytical solution that we have introduced will help to create a fast numerical algorithm for computers and thus simplify the numerical solutions of higher order physical problems.
Abstract
We suggest a practical method for obtaining the particular solution of non-homogeneous higher order linear differential equations with constant coefficients. The proposed [...]
- 225
- read
Modal and dynamic analysis of a footbridge in service
N. Frechilla, M. Cacho-Pérez, A. Lorenzana

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 18

Abstract
Civil engineering constructions like pedestrian footbridges are structures increasingly slender, ambitious and complex in which the dynamic effects caused by the loads to which they are subjected (pedestrians) may induce service problems and / or significant or repetitive amplifications of the efforts and deformations. This fact together with the current social demands related to the perception and comfort raise the need to integrate the analysis and computer-aided design in the evaluation of the vibrations generated by the loads this type of structures supports. In the specific case of finite element commercial programs, their use has not proliferated as much as in other engineering fields due to the existence of simplified methodologies in numerous national and international guidelines and regulations and the difficulty of making realistic models in the case of complex structures. However, the knowledge generated by the analysis of this type of numerical models would be especially useful in the earlier phases of the design of similar structures, so much initial as of the necessary modifications to solve existing dynamic problems, since it is in these stages when the best solution could be applied from both a technical and an economic point of view. This article describes the process of generation and updating of the mechanical finite element model (FEM) of a footbridge in service and the simulation of two types of load: an excitation generated by a shaker and a pedestrian load, contrasting the results generated by the numerical model with those obtained experimentally.
Abstract
Civil engineering constructions like pedestrian footbridges are structures increasingly slender, ambitious and complex in which the dynamic effects caused by the loads to [...]
- 308
- read
Parallelization using a BDD-C of a multiscale strategy with non lineal localization based on a NKS
J. Hinojosa, K. Saavedra, G. Pincheira

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 19

Abstract
In previous works, the nonlinear localization was first presented and studied in the case of large displacements but only for globally stable structural responses. In this paper, the parallelization of this computational strategy using a Balancing Domain Decomposition by Constrains (BDD-C) is presented. Finally, a validation of this implementation is carried out in lineal elasticity, verifying the ''speed-up'' and the numerical extensibility.
Abstract
In previous works, the nonlinear localization was first presented and studied in the case of large displacements but only for globally stable structural responses. In this [...]
- 146
- 4/5
- read
Modeling the effects of high strain rate loading on RC columns using Arbitrary Lagrangian Eulerian (ALE) technique
M. Abedini, A. Mutalib, S. Raman, E. Akhlaghi

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 24

Abstract
In recent years, many studies have been conducted by governmental and nongovernmental organizations across the world in an attempt to better understand the effect of explosive loads on buildings in order to better design against specific threats. This study is intended to contribute to increase the knowledge about how explosions affect reinforced concrete (RC) columns. In this study, a nonlinear model is developed to study the blast response of RC columns subjected to explosive loads. Numerical modeling of RC column under explosive load is presented using advanced finite element code LS DYNA. The obtained numerical model is validated with the experimental test and the results are in substantial agreement with the experimental data. ALE method for blast analysis is presented in the current research. The effects of scaled distance on the damage profile of RC columns are investigated. The results demonstrate that the level of damage increased with describing the scaled distance. Also the results shown duration for the blast loading, and hence the impulse, varies with charge masses at the specified scaled distance. Higher magnitude charge masses produced longer blast loading durations than lower magnitude charge masses. This means that at the same scaled distance, a charge mass of higher magnitude produced a higher impulse than the lower magnitude charge mass. The findings of this research represent the scaled distance is an important parameter that should be taken into account when analyzing the behavior of RC columns under explosive effects. The data collected from this research are being used to improve the knowledge of how structures will respond to a blast event, and improve finite element models for predicting the blast performance of concrete structures.
Abstract
In recent years, many studies have been conducted by governmental and nongovernmental organizations across the world in an attempt to better understand the effect of explosive [...]
- 411
- read
Two-dimensional numerical simulation of channel flow with submerged obstacles using the lattice Boltzmann method
J. Cargnelutti, V. Galina, E. Kaviski, L. Gramani, A. Lobeiro

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 20

Abstract
A two-dimensional numerical simulation of the water flow in a rectangular channel with submerged obstacles distributed alternately along its banks is presented. The governing equations of flow are the shallow water equations, which will be solved by the Boltzmann lattice method (LBM) with multiple relaxation times (MRT). The non-slip bounce-back scheme was used on walls and obstacles, constant discharge at the inlet and fixed depth at the outlet of the channel. Due to the characteristics of the problem to be simulated, a large eddy simulation (LES) technique was incorporated into the computational code, which allows to obtain results that are closer to the actual behavior of the flow. In addition, the stability of the simulation at all points of the mesh is evaluated for each step of time and, together with the property of the consistency of the LBM, the convergence of the solution is obtained. The simulation provides the depth, velocities in the x and y directions, and the magnitude of water vorticity.
Abstract
A two-dimensional numerical simulation of the water flow in a rectangular channel with submerged obstacles distributed alternately along its banks is presented. The governing [...]
- 247
- read
Nonlinear dynamic analysis of structures in contact with soil
L. Rosas, A. Silva, R. Silveira

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 14

Abstract
Structural elements, in many situations, are supported by other surfaces, such as soil, which may offer movement constraints in some directions. Therefore, the static and dynamic analysis of these elements considering their interaction with the soil becomes important in the design of a structural design. This paper presents the nonlinear dynamic analysis of structural systems considering such interaction through the Finite Element Method. A geometrically nonlinear beam-column element is used to model the structure, while the soil can be idealized as a continuum foundation, through the Winkler and Pasternak models. It is assumed that the foundation reacts to tension and compression stresses, so during the deformation process the structural elements are subjected to bilateral contact constraints. The analysis is based on the modeling of the structural system using the finite element method, where the Newmark integration method and Newton-Raphson iterative strategy are used in the process of solving the nonlinear dynamic equations in the time domain. Practical situations involving the interaction between soil and structure were evaluated during the study, showing the influence of contact in the natural vibration frequency and transient response of these structures.
Abstract
Structural elements, in many situations, are supported by other surfaces, such as soil, which may offer movement constraints in some directions. Therefore, the static and [...]
- 184
- 5/5
- read
Galoisian and numerical approach of three dimensional linear differential systems with skew symmetric matrices defined in a non- constant differential field
P. Acosta-Humánez, M. Jiménez, J. Ospino

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 8

Abstract
This work contrasts numerical methods with algebraic methods. These methods are applied to solve a three dimensional linear differential system with skew symmetric matrices defined in a non- constant differential field. Algorithms and methods of Differential Galois Theory, are used to provide an algebraic solution, while numerical methods, in particular, methods from Runge - Kutta family, are applied to the same system. Finally, the absolute and relative errors between Liouvillians solution are calculated comparing the solutions obtained by means of algebraic methods and by means of numerical methods.
Abstract
This work contrasts numerical methods with algebraic methods. These methods are applied to solve a three dimensional linear differential system with skew symmetric matrices [...]
- 234
- 5/5
- read
Composite slabs micromechanics characterization of the steel-concrete interaction with finite element models
A. Plans, D. Alamillo, M. Ferrer, F. Marimon

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 22

Abstract
This study focuses on the improvement of composite slabs characterization throughout the use of advanced finite elements models. The accurate three-dimensional modelling of a full scale commercial steel sheet and concrete slab geometries enables the analysis of the composite slab micromechanics. The inclusion of the embossments depth and slope, the steel sheet thickness, the tilting angle, the length and width and spacing of embossments, and the profiling angle of the rib shape removes the need of simplifications for the complex phenomenon at the steel – concrete interface. The accuracy observed at the finite element models once compared with the laboratory specimens enables a new approach to describe the complex stress distributions in composite slabs. In particular, this study introduces a novel representation of the longitudinal shear strength tu and a newly defined vertical normal stress σu between the steel and concrete that frequently define the overall composite slab bearing capacity. Subsequently, this study compares detailed stress diagrams and deformations from the finite elements models with experimental data obtained through piezoelectric gauges at the laboratory specimens.
Abstract
This study focuses on the improvement of composite slabs characterization throughout the use of advanced finite elements models. The accurate three-dimensional modelling of [...]
- 230
- read
A 4-node thin shell element based on co-rotational for laminated composite structures
S. Qiao, H. Gao, L. Hua, F. Wang

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 12

Abstract
The finite formulation of the 4-node thin shell element based on Co-rotational (CR) and Timoshenko`s theory was presented for the analysis of laminated composite structures. Based on the Timoshenko`s theory the present thin shell element avoids shear locking behavior, and a bilinear in-plane displacement field is introduced for the coupling of in-plane and bending actions, and such element performs simple formulation and highly efficienct. A highly efficient CR formulation was also established to define the motion of the element with large displacement. The characteristics of the element are more pronounced when shells get thin, each node of the 4-node element has five degrees of freedom. An incremental iterative method based on the Newton Raphson method was used to solve the nonlinear equilibrium equations. A number of numerical examples were given to verify that the formula is computationally efficient and the results showed good agreement.
Abstract
The finite formulation of the 4-node thin shell element based on Co-rotational (CR) and Timoshenko`s theory was presented for the analysis of laminated composite structures. [...]
- 318
- read
Comparison of algorithms for reliability-based structural optimization
H. Cortés, C. Camacho Lopez, R. Calvo OCampo

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 1

Abstract
The design of reliable structures requires robust tools that allow the analysis of the behavior of the system subject to variability in its resistance and applied loads. For this, there are several formulations and computational algorithms that enable to model the structural behavior under uncertainties. Under these requirements, the most popular and reliable optimum design methodology is the reliability based optimization (RBO), which should be implemented through the combination of high fidelity mathematical or computational models, e.g. finite element models, efficient and accurate reliability estimation methods, and efficient and effective engineering optimization algorithms. Most RBO applications for structural optimization has the latest developments in efficient computational techniques for simulation and reliability calculations, however, although a variety of optimization methods exist, they generally do not perform a selection of the optimization algorithm more appropriate for each application. In this context, the main contribution of this article is the performing of a comparative study of the computational performance of optimization algorithms applied in structural optimization by RBO. The study compared the numerical performance of optimization algorithms in three problems. Compared algorithms correspond to derivative based algorithms, direct search algorithms, and bioinspired algorithms; including the most representative algorithms of each category. The results of the comparative study point out advantages and disadvantages of the use of the different types of algorithms and allow to conclude on the criteria that must be considered for the choice of an algorithm that favors the computational performance.
Abstract
The design of reliable structures requires robust tools that allow the analysis of the behavior of the system subject to variability in its resistance and applied loads. For [...]
- 360
- 5/5
- read
Research on rational layout of strut arms of tainter gate in vertical frame
X. Zhang, Z. Wang, D. Sun

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 15

Abstract
The overall stability of hydraulic tainter steel gate decrease seriously, and they are caused by improper structure layout of the two-way eccentric compression of struts. Chinese and American specification method, structural mechanics method and finite element method are respectively used to study rational structural layout of strut arms in vertical frame. First of all, a unified method for rational layout of struts of tainter gate in vertical frame is deduced by using structural mechanics method that simplifies curve girder as straight girder on the basis of zero rotation in vertical girder. Second, rational layouts of struts were researched by utilizing spatial finite element method according to zero rotation in vertical girder. The 756 groups rational layout results of the above three methods with different water heads, different number of struts and different unit stiffness ratios were researched. The differences of struts stress and material dosages of various rational layout methods were evaluated. From the point of view of the forces of tainter gate struts in vertical frame, as the results shown, the layouts of struts by Chinese and American specification method, straight beam method and finite element method are large eccentric compression, small eccentric compression and axial compression respectively. The layout of struts with specification method in lower head is quite different from straight beam method and finite element method, and the layouts of deep water head with straight beam method and finite element method are tend to be consistent. Unit stiffness ratio between vertical girder and strut has little effect on layout of tainter gate struts, but has a great influence on material dosages of tainter gate. Compared with specification method, layout of tainter gate with two struts and three struts by using straight beam method and finite element method can improve stability of struts and save materials of overall tainter gate structure, and the material saving rates of tainter gate with two struts and three struts with finite element method are respectively [32.63, 47.58] (%) and [21.61, 30.01] (%). Rational layout concise charts of tainter gate with two struts and three struts by specification method, straight beam method and finite element method are given, which can be used directly for projects designs. Compared with specification method, the layout of struts of straight beam method and finite element method is not only security and economy, but also method and mechanics concept are simple, which can provide the theoretical basis for specification revision of Chinese and American.
Abstract
The overall stability of hydraulic tainter steel gate decrease seriously, and they are caused by improper structure layout of the two-way eccentric compression of struts. [...]
- 262
- 5/5
- read
Fuzzy inference system for muti-hazard physical risk assessment in urban areas
M. Carreño, N. Lantada, N. Jaramillo

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 13

Abstract
The urban areas may be exposed to different natural hazards; in order to jointly evaluate the potential risk, this article proposes a methodology for the qualitative assessment of the multi-hazard physical risk by using a fuzzy inference system called MuHRA by its abbreviations MUlti-Hazard Physical risk assessment. This methodology is based on the fuzzy sets theory and uses expert opinions. It is applicable to the risk evaluation involving a maximum of three natural hazards and uses five levels of risk: very low, low, medium, high and very high. The proposed methodology considers the physical risk in an urban area involving at least three potential effects: predominant damage that varies with the type of hazard; impact on the population, and damage in lifelines. According to the available information for the urban area to be assessed, the physical risk to a natural hazard can be evaluated, either through expert opinion or a more detailed assessment, and then they are combined and synthesized into a single multi-hazard physical risk index (RFmh). The MuHRA methodology is applied to the multi-hazard risk evaluation for the city Merida-Venezuela considering both, the seismic hazard and the landslides. This application shows the versatility and robustness of the methodology, which can be adapted according to the information available in each case study.
Abstract
The urban areas may be exposed to different natural hazards; in order to jointly evaluate the potential risk, this article proposes a methodology for the qualitative assessment [...]
- 201
- read
The geological history analysis of the friction angle in transported soils and their importance in the bearing capacity of shallow foundations
C. Mendoza, J. Ruge, B. Caicedo

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 11

Abstract
This work shows the variability of the friction angle based on the geological history, over the bearing capacity of shallow foundations. This study was developed through the generation of random fields of friction angle using the matrix decomposition technique for a self-correlated lognormal distribution. In addition, to recreate the geological history, the anisotropic random fields were created using the rotation matrix with angles of 0, 45 and 90 degrees. Subsequently, these random fields were implemented in a finite element model of a continuous footing. A linear elastoplastic constitutive model was selected to represent stress-strain soil behavior together with the Mohr-Coulomb failure criteria. This last work was done in order to understand the influence of geological history and the variability of the friction angle in the bearing capacity of shallow foundations. Results include the weight of the variability of the friction angle in the bearing capacity and the influence of the dip over the friction angle and the bearing capacity.
Abstract
This work shows the variability of the friction angle based on the geological history, over the bearing capacity of shallow foundations. This study was developed through the [...]
- 399
- read
Sustainable Pedestrian Bridge using Advanced Materials (SUPERBAM)
L. Pellegrini, R. Ribó, J. Jordan, J. Sobrino

[ramsan] (2017). 1

Abstract
Fiber-reinforced polymer pedestrian bridges are becoming a competitive alternative to conventional concrete or steel pedestrian bridges in the span range from 5 to 30 m. In order to consider it as a viable alternative, it is necessary, among other things, to be price competitive in the total cost of the bridge, including construction and full-life maintenance. One of the ways of making the cost competitive is to normalize a few cross-sections and create a catalog of standard cross-sections and shapes depending on the load conditions and ranges of spans. The objective of this work has been to create this catalog, taking into account the following items: A detailed economic analysis of the impact of every sub cost in the total construction and maintenance cost. A detailed structural analysis and optimization, by using MEF, of different cross-section and laminate solutions has been carried out, both under static and dynamic loads, in order to achieve the best possible design. The preparation of a specialized FEM analysis software that already includes in its database the chosen laminates as well as automatized geometrical construction and standarised load cases definition. With all these tools, it is possible to make highly reusable molds for the laminates and it is possible to make the final cost of the FRP pedestrian bridge more competitive.
Abstract
Fiber-reinforced polymer pedestrian bridges are becoming a competitive alternative to conventional concrete or steel pedestrian bridges in the span range from 5 to 30 m. In [...]
- 249
- read
Application of Lattice Boltzmann Method for Surface Runoff in Watershed
V. Galina, J. Cargnelutti, E. Kaviski, L. Gramani, A. Lobeiro

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 10

Abstract
Derived from simplifications of the Saint-Venant equations, the kinematic wave model has the ability to describe the behavior of surface runoff in watersheds. This paper aims to obtain the numerical simulation of the flow routing in a natural watershed, by using lattice Boltzmann method. In the computational model, the surface of the basin will be represented by a V-shaped segmented in two lateral planes and one main channel. The simulation considers the effective precipitation flowing on the watershed per unit of width at the exit of each of the planes that represent the surface of the basin. The water flowing from the planes enters the main channel in the form of lateral contribution. Hydrograms of two rain events are obtained, which present the volume drained in the outlet corresponding to the whole basin in each event. Two equilibrium distribution functions were developed by Chapmann-Enskog expansion at time scales and model D1Q3, one suitable for flow on the basin surface and another for the main channel, in order to obtain the variables of interest in each case. The numerical results obtained were compared with the KINEROS2 hydrological model.
Abstract
Derived from simplifications of the Saint-Venant equations, the kinematic wave model has the ability to describe the behavior of surface runoff in watersheds. This paper aims [...]
- 271
- read
Nonlinear analysis of beams, plane frames and arch using a dierent co-rotating beam element
W. Matias Silva, S. Silva, M. Gutiérrez

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 17

Abstract
The present work uses a co-rotating approach for obtain the internal forces and tangent stiness matrices for three plane beam elements. All of them are based on the same co-rotational approach, and di er by the strain de nition used in the local co-rotational coordinate system. Based on the Bernoulli assumption, the rst two elements use a linear and a shallow arch strain de nition, respectively. The third element is based on the Timoshenko assumption with linear interpolations for the displacements. Some examples are presented and the numerical results demonstrate that the beam elements here presented are able to perform the nonlinear analysis of plane frames and 2D arches and to handle large rotations too.
Abstract
The present work uses a co-rotating approach for obtain the internal forces and tangent stiness matrices for three plane beam elements. All of them are based on the same co-rotational [...]
- 203
- read
Application of the Verlet method for the simulation of a gravitational system of n bodies
J. Medina, C. Acosta, M. Flota-Bañuelos, R. Peón-Escalante

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 16

Abstract
In this paper we propose a numerical solution (software simulation) of the "problem of n bodies" that interact gravitationally based on the formulation of Verlet. Additionally a program is designed that graphically shows the results of this numerical solution, which details the different trajectories, for different conditions of mass, speed and distance between the n objects that interact. The interaction of the user with the graphical interface, is performed particle by particle.
Abstract
In this paper we propose a numerical solution (software simulation) of the "problem of n bodies" that interact gravitationally based on the formulation of Verlet. [...]
- 567
- read
Control law for a robot network formation using static diffusive coupling
S. Durazo-Acevedo, A. Aguilar-Bustos, E. Bugarin

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 7

Abstract
This article describes a control proposal for a formation objective of a robot network in collaborative work with static diffusive coupling using tools derived from graph theory. This proposal is guaranteed by the stability theory of Lyapunov and it is validated with results in simulation and experimentation. As an important part of this work, it is detailed like a tutorial the procedure for the formulation of the robot network addressed and also it is proposed a formation control law with procedure for non-collision between the robots that form the network using the same network topology.
Abstract
This article describes a control proposal for a formation objective of a robot network in collaborative work with static diffusive coupling using tools derived from graph [...]
- 202
- read
Advances in the DEM and coupled DEM and FEM techniques in non linear solid mechanics
E. Oñate, F. Zarate, M. Celigueta, J. Gonzalez, J. Miquel, J. Carbonell, F. Garcia, S. Latorre, M. Santasusana

(2017). Research Report, Nº PI416

Abstract
In this chapter we present recent advances in the Discrete Element Method (DEM) and in the coupling of the DEM with the Finite Element Method (FEM) for solving a variety of problems in non linear solid mechanics involving damage, plasticity and multifracture situations.
Abstract
In this chapter we present recent advances in the Discrete Element Method (DEM) and in the coupling of the DEM with the Finite Element Method (FEM) for solving a variety of [...]
- 185
- read
A memetic algorithm based on Artificial Bee Colony for optimal synthesis of mechanisms
E. Vega-Alvarado, E. Portilla-Flores, G. Munoz-Hernandez, E. Mezura-Montes, G. Sepúlveda-Cervantes, P. Bautista-Camino

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 3

Abstract
In this paper a novel proposal of a modular hybrid algorithm as a tool for solving real-world engineering problems is presented. A memetic algorithm, MemMABC, is implemented with this approach and applied to solve two case studies of mechanism design, in order to evaluate its efficiency and performance. Because of its modularity, the proposed algorithm is simple and flexible; these features make it quite reusable to be applied on different optimization problems, with a wide scope. The solutions of the optimization problems are also modular, following a scheme of structured programming that includes the use of global variables for configuration, and subroutines for the objective function and the restrictions. Memetic algorithms are a good option to solve hard optimization problems, because of the synergy derived from the combination of their components: a global search population-based metaheuristic and a local refinement method. The quality of simulation results suggests that MemMABC can be successfully applied to solve hard problems in engineering design.
Abstract
In this paper a novel proposal of a modular hybrid algorithm as a tool for solving real-world engineering problems is presented. A memetic algorithm, MemMABC, is implemented [...]
- 439
- read
Robust topology optimization of continuum structures using Monte Carlo method and Kriging models
A. Cordero, P. Martí, M. Victoria

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 5

Abstract
The aim of this paper is to introduce an efficient and accurate new approach called Monte Carlo and Kriging (MCK) to robust topology optimization. The objective is to minimize the expected value of ''compliance'' under concentrated loading uncertainty. The loading uncertainty may occur in magnitude, direction and/or position. The Monte Carlo simulation method and Kriging model are used to evaluate the objective function. To evaluate the expected value of ''compliance'' the probabilistic problem is transformed into a multiple loading deterministic one using of Monte Carlo method but with a reduced evaluations number of simulation model. A small sample obtained with a Latin Hypercube is used to build a Kriging model of the simulation model. This is utilized to estimate the ''compliance'' in those points used by Monte Carlo simulation method. Two problems are solved to demonstrate the efficiency and accuracy of the approach. The examples are solved again using a standard Monte Carlo simulation to check the proposed approach.
Abstract
The aim of this paper is to introduce an efficient and accurate new approach called Monte Carlo and Kriging (MCK) to robust topology optimization. The objective is to minimize [...]
- 262
- read
Vigas de hormigón armado reforzadas a flexión con materiales tipo Fabric-Reinforced Cementitious Matrix. Estudio experimental y analítico
C. Escrig, L. Gil

Monograph CIMNE (2017). M171

Abstract
Actualmente, existen en el mercado numerosas opciones que permiten aplicar refuerzos de matriz cementítica en estructuras en servicio. A pesar de ello, el conocimiento relativo a las propiedades del material, así como del comportamiento mecánico de las estructuras de hormigón armado reforzadas con TRM es, más bien, escaso. En la investigación llevada a término, se ha estudiado y comparado el comportamiento de diferentes tipos de TRM, tanto a nivel de caracterización de sus propiedades mecánicas, como relativo a refuerzo estructural a flexión de vigas de hormigón armado. A continuación se exponen las principales conclusiones extraídas de los diferentes capítulos del presente trabajo.
Abstract
Actualmente, existen en el mercado numerosas opciones que permiten aplicar refuerzos de matriz cementítica en estructuras en servicio. A pesar de ello, el conocimiento [...]
- 289
- read
A machine learning based methodology for anomaly detection in dam behaviour
F. Salazar, E. Oñate, M. Toledo

Monograph CIMNE (2017). M170

Abstract
Dam behaviour is difficult to predict with high accuracy. Numerical models for structural calculation solve the equations of continuum mechanics, but are subject to considerable uncertainty as to the characterisation of materials, especially with regard to the foundation. As a result, these models are often incapable to calculate dam behaviour with sufficient precision. Thus, it is difficult to determine whether a given deviation between model results and monitoring data represent a relevant anomaly or incipient failure. By contrast, there is a tendency towards automatising dam monitoring devices, which allows for increasing the reading frequency and results in a greater amount and variety of data available, such as displacements, leakage, or interstitial pressure, among others. This increasing volume of dam monitoring data makes it interesting to study the ability of advanced tools to extract useful information from observed variables. In particular, in the field of Machine Learning (ML), powerful algorithms have been developed to face problems where the amount of data is much larger or the underlying phenomena is much less understood. In this monograph, the possibilities of machine learning techniques are analysed for application to dam structural analysis based on monitoring data. The typical characteristics of the data sets available in dam safety are taking into account, as regards their nature, quality and size. A critical literature review is performed, from which the key issues to consider for implementation of these algorithms in dam safety are identified. A comparative study of the accuracy of a set of algorithms for predicting dam behaviour is carried out, considering radial and tangential displacements and leakage flow in a 100-m high dam. The results suggest that the algorithm called “Boosted Regression Trees” (BRT) is the most suitable, being more accurate in general, while flexible and relatively easy to implement. The possibilities of interpretation of the mentioned algorithm are evaluated, to identify the shape and intensity of the association between external variables and the dam response, as well as the effect of time. The tools are applied to the same test case, and allow more accurate identification of the time effect than the traditional statistical method. Finally, a methodology for the implementation of predictive models based on BRT for early detection of anomalies is presented, together with its implementation in an interactive tool that provides information on dam behaviour, through a set of selected devices. It allows the user to easily verify whether the actual data for each of these devices are within a pre-defined normal operation interval.
Abstract
Dam behaviour is difficult to predict with high accuracy. Numerical models for structural calculation solve the equations of continuum mechanics, but are subject to considerable [...]
- 248
- read
Numerical Techniques for non-linear analysis of structures combining Discrete Element and Finite Element Methods
M. Santasusana, E. Oñate

Monograph CIMNE (2016). M168

Abstract
This works encompasses a broad review of the basic aspects of the Discrete Element Method for its application to general granular material handling problems with special emphasis on the topics of particle-structure interaction and the modelling of cohesive materials. On the one hand, a special contact detection algorithm has been developed for the case of spherical particles representing the granular media in contact with the finite elements that discretize the surface of rigid structures. The method, named Double Hierarchy Method, improves the existing state of the art in the field by solving the problems that non-smooth contact regions and multi contact situations present. This topic is later extended to the contact with deformable structures by means of a coupled DE-FE method. To do so, a special procedure is described aiming to consistently transfer the contact forces, which are first calculated on the particles, to the nodes of the FE representing the solids or structures. On the other hand, a model developed by Oñate et al. for the modelling of cohesive materials with the DEM is numerically analysed to draw some conclusions about its capabilities and limitations. In parallel to the theoretical developments, one of the objectives of the thesis is to provide the industrial partner of the doctoral programme, CITECHSA, a computer software called DEMPack (www.cimne.com/dem/) that can apply the coupled DE-FE procedure to real engineering projects. One of the remarkable applications of the developments in the framework of the thesis has been a project with the company Weatherford Ltd. involving the simulation of concrete-like material testing.
Abstract
This works encompasses a broad review of the basic aspects of the Discrete Element Method for its application to general granular material handling problems with special emphasis [...]
- 120
- read
Probabilistic dynamic analysis of steel buildings with long duration earthquakes
S. Díaz, . L.G.Pujades, A. Barbat, D. Hidalgo, Y. Vargas

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 6

Abstract
The probabilistic analysis of the seismic performance of a structure requires quantifying the uncertainties of the involved variables and parameters, including the seismic action and mechanical properties of its elements. In this article, the seismic performance of high-rise, mid-rise and low-rise of steel buildings, subjected to long duration seismic actions like those of Mexico City, is analyzed. The analysis is conducted by using a probabilistic approach. The seismic actions are selected to be compatible with the design spectra of the Mexican seismic code for soft soils and long duration earthquakes, characteristic for this region. The dynamic analyses are performed by using Monte Carlo simulations. The strength and ductility of the beams and columns are considered random variables; the seismic actions are also modelled in a probabilistic way. The damage index of Park and Ang is used. The results show that the uncertainties expected in the response are significant, being the randomness of the seismic action the main cause. From the comparison between the mean values of the probabilistic approach and those corresponding to the deterministic case, a good consistency of the result obtained for low-rise and mid-rise buildings is observed. Nevertheless, the consistency is lower in the case of high-rise buildings. The analyzed low-rise and mid-rise buildings show a good seismic performance to seismic actions, but the high-rise buildings show slight or moderate damage. It is concluded that the probabilistic approach provides a more complete information on the structural response.
Abstract
The probabilistic analysis of the seismic performance of a structure requires quantifying the uncertainties of the involved variables and parameters, including the seismic [...]
- 418
- 5/5
- read
Numerical study of PCMs melting process in cylindrical cavity
J. Estrazulas, R. Oliveski

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 2

Abstract
Several residential, commercial and industrial applications have their efficiency increased when a thermal energy storage system is incorporated. The PCMs (Phase Change Materials), due to their high latent heat of fusion, are materials that represent a viable alternative to the implementation of thermal energy storage systems. This paper presents a numerical study of RT (Rubitherm Technologies GmbH) PCMs family fusion process in cylindrical cavities. The study was conducted through a CFD ''(''Computational Fluid Dynamics) numerical simulation, with ANSYS Fluent software. The numeric model adopted is two-dimensional and has been validated with numerical and experimental results of literature, achieving a good approximation. For PCMs here studied, increasing the temperature from 10 ''oC'' to 20 ''oC'' and 10 ''oC'' to 30 ''oC'', above the phase change temperature, for liquid fractions between 0.4 and 0.8, the average reduction of fusion time is approximately 55.8% and 71.8 %, respectively.
Abstract
Several residential, commercial and industrial applications have their efficiency increased when a thermal energy storage system is incorporated. The PCMs (Phase Change Materials), [...]
- 257
- read
Automatic remeshing algorithm of triangular elements during finite element analyses
A. Hermosillo-Arteaga, M. Romo, R. Magaña, J. Carrera

Rev. int. métodos numér. cálc. diseño ing. (2018). Vol. 34, (1), 4

Abstract
In this paper an automatic remeshing algorithm of triangular finite elements is presented. It is well known that the element sizes of the mesh play an important role in modeling the continuum, particularly when notable material properties differences exist in contiguous areas of the medium. In such cases, the mesh must be fine enough in such areas in order to obtain reliable results. Therefore, in this paper is advanced an algorithm to carry out automatic remeshing of local areas where the “remeshing” criteria is activated to refine the mesh accordingly. Herein the proposed algorithm integrated into a two dimensional finite element computer program is used to analyze a classical geotechnical problem to show the importance of locally refining the mesh and to demonstrate that regardless of the geometric characteristics of the initial mesh, the algorithm yields practically equal results. Computations with the proposed method are compared with the corresponding close form solutions, whenever available, to show the usefulness and reliability of the remeshing algorithm. Furthermore, to show the algorithm’s versality, the initial loading boundary conditions considered for the cases included in this paper are modified in order to show how the automatic local remeshing is capable of adapting the initial mesh configuration into a new one as a function of the new boundary conditions. As shown in the paper, the final resulting meshes for both load boundary conditions considered are appreciably dissimilar from each other, which leads to somehow different results.
Abstract
In this paper an automatic remeshing algorithm of triangular finite elements is presented. It is well known that the element sizes of the mesh play an important role in modeling [...]
- 241
- read
Comportamiento sísmico de puentes atirantados y disipación de energía adicional: un estado del conocimiento
G. Valdebenito, A. Aparicio

Monograph Series in Earthquake Engineering, editor A. H. Barbat (2005). MIS55

Abstract
Las siguientes páginas corresponden a la presentación de los últimos avances y novedades en materia de comportamiento sísmico de puentes de tirantes de gran luz. La idea ha surgido de la necesidad de unificar experiencias y criterios, y tiene como objetivo presentar al lector una visión actualizada acerca del comportamiento de estos sistemas y la reciente introducción y uso de sistemas avanzados adicionales de protección pasiva y activa. A modo introductorio, se presentan los aspectos generales del comportamiento de puentes de tirantes frente a cargas estáticas. Se exponen los resultados de las investigaciones más recientes acerca del comportamiento sísmico general de puentes de tirantes de gran luz, se analiza la problemática de la caracterización de la acción sísmica de entrada, se presentan los desarrollos y resultados de investigaciones recientes en materia de dispositivos de control de vibraciones aplicado a puentes, se analiza la temática del comportamiento sísmico de puentes de tirantes con incorporación de sistemas pasivos y activos y finalmente se presentan algunos aspectos básicos y actualizados relacionados con el análisis y diseño estructural.
Abstract
Las siguientes páginas corresponden a la presentación de los últimos avances y novedades en materia de comportamiento sísmico de puentes de tirantes [...]
- 838
- read
Probabilistic seismic hazard and risk assessment in Spain
M. Salgado-Gálvez, O. Cardona, M. Carreño, A. Barbat

Monograph Series in Earthquake Engineering, editor A. H. Barbat (2015). MIS69, ISBN: 978-84-943307-7-3

Abstract
This work attempts to explain how probabilistic seismic risk assessments can be performed at different resolution levels, using, strictly speaking, the same methodology (or arithmetic) and, then, how to obtain results in terms of the same metrics; but, also, highlighting what the differences in terms of inputs for the analysis and the reasons for them (i.e. including the dynamic soil response effects which are only relevant in local assessments) are. First, a country level assessment is first performed with similarities to the presented by Cardona et al. (2014) using a coarse-grain exposure database that includes only the building stock in the urban regions of Spain. Second, a urban seismic risk assessment with the detail of state-of-the-art studies such as the ones developed by Marulanda et al. (2013) and Salgado-Gálvez et al (2013; 2014a) is performed for Lorca, Murcia. In both cases, the fully probabilistic seismic risk results are expressed in terms of the loss exceedance curve which corresponds to the main output of said analysis from where different probabilistic risk metrics, such as the average annual loss and the probable maximum loss, as well as several other relationships, can be derived (Marulanda et al., 2008; Bernal, 2014). Because of the damage data availability for the Lorca May 2011 earthquake, a comparison between the observed losses and those modelled using an earthquake scenario with similar characteristics in terms of location, magnitude and spectral accelerations was done for the building stock of the city. The results of the comparison are presented in terms of expected losses (in monetary terms) and damage levels related to the obtained the mean damage ratios compared with the observed by post-earthquake surveys.
Abstract
This work attempts to explain how probabilistic seismic risk assessments can be performed at different resolution levels, using, strictly speaking, the same methodology (or [...]
- 49
- read
Robust volume mesh generation for non-watertight geometries
A. Coll, P. Dadvand, E. Oñate

Monograph CIMNE (2014). M146

Abstract
Nowadays large part of the time needed to perform a numerical simulation is spent in preprocessing, especially in the geometry cleaning operations and mesh generation. Furthermore, these operations are not easy to automatize because they depend strongly on each geometrical model and they often need human interaction. Many of these operations are needed to obtain a watertight geometry. Even with a clean geometry, classical unstructured meshing methods (like Delaunay or Advancing Front based ones) present critical weak points like the need of a given quality in the boundary mesh or a relatively smooth size transition. These aspects decrease their robustness and imply an extra e ort in order to reach the nal mesh. Octree based meshers try to relax some of these requirements. In the present work an octree based mesher for unstructured tetrahedra is presented. The proposed mesher ensures the mesh generation avoiding most of the geometry cleaning operations. It is based in the following steps: t an octree onto the model, re ne it following given criteria, apply a tetrahedra pattern to the octree cells and adapt the tetrahedra close to the contours in order to represent accurately the boundary shape. An important and innovative aspect of the proposed algorithm is it ensures the nal mesh preserves the topology and the geometric features of the original model. The method uses a Ray Casting based algorithm for the identi cation of the inner and outer parts of the volumes involved in the model. This technique allows the mesh generation of volumes even with non-watertight boundaries, and also opens the use of the mesher for immersed methods only applying slight modi cations to the algorithm. The main advantages of the presented mesher are: robustness, no need for watertight boundaries, independent on the contour mesh quality, preservation of geometrical features (corners and ridges), original geometric topology guaranteed, accurate representation of the contours, valid for immersed methods, and fast performance. A lot of time in the preprocessing part of the numerical simulation is saved thanks to the robustness of the mesher, which allows skipping most of the geometry cleaning operations. A shared memory parallel implementation of the algorithm has been done. The e ectiveness of the algorithm and its implementation has been veri ed by some validation examples.
Abstract
Nowadays large part of the time needed to perform a numerical simulation is spent in preprocessing, especially in the geometry cleaning operations and mesh generation. Furthermore, [...]
- 143
- read
On using linear elements in incompressible plane strain problems. A simple edge based approach for triangles
B. Boroomand, B. Khalilian

(2004). Research Report, Nº PI248

Abstract
In this paper a simple iterative method is presented for finite element solution of incompressible plane strain problems using linear elements. Instead of using a mixed formulation approach, we use an equivalent displacement/velocity approach in an iterative manner. Control volumes are taken for regions where are to exhibit incompressible behavior. For triangular elements the control volume is chosen as the area built on the parts of each pair of elements at the sides of an edge. In this case, elements are let to exchange volume. It is shown that the proposed edge based approach removes the deficiency of the linear triangular elements i.e. locking effect.Similar edge based approach is applied to the linear quadrilateral elements. However, if the control volume is chosen as the element volume the formulation gives similar results as the discontinuous mixed formulation using one pressure point without exhibiting instability behavior. The formulation is based on decomposition of the displacement/velocity field into deviatoric and volumetric parts. The volumetric part is iteratively eliminated without confronting locking or instability phenomenon. The iterative procedure is very cheap and simple to be implemented in any FEM code. Several examples are given to demonstrate the performance of the procedure.
Abstract
In this paper a simple iterative method is presented for finite element solution of incompressible plane strain problems using linear elements. Instead of using a mixed formulation [...]
- 34
- read
Calibración de funciones de atenuación basadas en el espectro de fuente radiado y su aplicación en Colombia
G. Bernal, O. Cardona

Monograph Series in Earthquake Engineering, editor A. H. Barbat (2015). MIS71, ISBN: 978-84-944244-2-7

Abstract
En esta monografía se propone el desarrollo de una metodología numérica para la calibración de un modelo de espectro de fuente a partir de información acelerográfica disponible. Esta metodología será aplicable a cualquier territorio donde se cuente con una muestra representativa de mediciones de movimiento sísmico.
Abstract
En esta monografía se propone el desarrollo de una metodología numérica para la calibración de un modelo de espectro de fuente a partir de información [...]
- 157
- read
Sistemas de ayuda a la decisión en ingeniería civil. posibilidades y perspectivas
E. Oñate, J. Marcipar, J. Piazzese

(2003). Research Report, Nº PI238

Abstract
La eclosión de las Tecnologías de la Información y las Comunicaciones (TIC), y en particular de Internet, ha facilitado el desarrollo de sistemas que, apoyados por bases de datos y potentes programas de simulación, transforman la información que existe en relación con un problema concreto, en conocimiento que permite tomar decisiones para su solución. Los denominados Sistemas de Ayuda a la Decisión (SAD) son ya una realidad en múltiples áreas de la ingeniería. En este trabajo se analizan las posibilidades y perspectivas de los SAD en ingeniería civil y se presentan tres ejemplos concretos de su aplicación a la prevención del riesgo de inundaciones y a la gestión de las emergencias correspondientes, al diseño de instalaciones en proyectos urbanísticos y a la gestión energética en municipios.
Abstract
La eclosión de las Tecnologías de la Información y las Comunicaciones (TIC), y en particular de Internet, ha facilitado el desarrollo de sistemas que, [...]
- 47
- read
Numerical simulation of fatigue processes. Application to steel and composite structures
L. Barbu, S. Oller, X. Martínez, A. Barbat

Monograph CIMNE (2016). M160

Abstract
The present work aims at advancing an innovative computational methodology that simulates steel and composite material fracture under cyclic loading following a phenomenological approach, with calibration from both small scale and large scale testing. This work addresses fatigue processes ranging from High Cycle to Ultra-Low-Cycle Fatigue. An assessment of the current state of the art is done for all the di erent fatigue types. Following, for Ultra-Low Cycle Fatigue a new constitutive law is proposed and validated with experimental results obtained on small scale samples. Industrial applications are shown for a large diameter straight pipe under monotonic loading conditions and for a bent pipe under cyclic loading. Emphasis is made on the capacity of the model to represent di erent failure modes depending on the loading conditions. The research regarding this part has been used in the frame of the European Project: \Ultra low cycle fatigue of steel under cyclic high-strain loading conditions" (ULCF). Regarding High Cycle Fatigue, a classic damage model is presented in combination with an automatic load advancing strategy that saves computational time when dealing with load histories of millions of cycles. Numerical examples are shown in order to demonstrate the capabilities of the advancing strategy and a validation of the model is done on small scale samples. A new constitutive model is presented for Low Cycle Fatigue that uses the classic plasticity and damage theories and simultaneously integrates both processes in the softening regime. The capabilities of the model are shown in numerical examples. Finally, the High Cycle Fatigue damage model is applied to the constituents of a composite material and the structural behaviour is obtained by means of the serial/parallel rule of mixtures. Validation of the constitutive formulation is done on pultruded glass ber reinforced polymer pro les.
Abstract
The present work aims at advancing an innovative computational methodology that simulates steel and composite material fracture under cyclic loading following a phenomenological [...]
- 177
- read
Seismic protection of cable-stayed bridges applying fluid viscous dampers
G. Valdebenito, A. Aparicio

Monograph Series in Earthquake Engineering, editor A. H. Barbat (2010). MIS62, ISBN: 978-84-96736-84-9

Abstract
Earthquakes can be really destructive. There is no doubt. Recent seismic events have demonstrated the important effects on structures, and especially on bridges. In this sense, cable-stayed bridges are not an exception, although their seismic performance during recent events has been satisfactory. Their inherent condition as part of life-lines makes the seismic design and retrofitting of such structures be seriously considered. Traditionally, seismic protection strategies have been based on provide enough strength and ductility. In the case of buildings or bridges with adequate supports and degrees of redundancy, that approach can be satisfactory, however, in the case of structures with few degrees of redundancy, or questionable ductility, that scheme could be inadequate, and worse, dangerous, as usually happens with cable-stayed bridges. All traditional modern strategies to design seismic structures are focused on the adequate comprehension of the mechanisms involved, in which ductility can be provided by some elements specially designed for these purposes. In these sense, strategies such as performed-based design or displacement-based design consider that well-designed structures need to dissipate enough energy by hysteresis in order to obtain economic and safe structures. The incorporation of additional energy dissipation and isolation devices, by means of passive, active, semi-active and hybrid strategies, constitutes without doubt efficient schemes to protect structures controlling or avoiding damage, in which the energy dissipation is guaranteed through the action of external elements specially designed for those purposes. By this way, now it is possible to provide enough strength and energy dissipation capacity at the same time, avoiding damage on important structural elements, with the subsequent guaranty of the functionality, very important on life-lines, even during strong ground motions. The present work constitutes an approach to the seismic protection of cable-stayed bridges including the incorporation of fluid viscous dampers as additional energy dissipation devices. The idea of the authors is to provide an up-to-date vision of the problem taking into account that long-period structures such as those proposed here, need to be adequately protected against strong motions, and considering that, because of their importance, an elastic behaviour is desirable. Chapter 1 describes the object to study in general terms. Chapter 2 constitutes a state-of-the-art review regarding the seismic behaviour and performance of fluid viscous dampers as external energy dissipation devices. The mechanical behaviour and technological aspects are now introduced with an energetic point of view, in which some practical applications are exposed and discussed. Chapter 3 describes the seismic response of cable-stayed bridges without external seismic protection, considering a parametric analysis in order to study the effects of the stay cable layout, stay spacing and deck level. A complete modal characterization is exposed, followed by a response spectrum analysis for comparative purposes. The effect of variations of the stay forces is analyzed, and finally, a nonlinear step-by-step analysis is performed for the critical structures, considering the velocity dependence of such bridges and the effects of far-fault and near-fault ground motions. The last Chapter exposes the seismic analysis of the selected structures including the incorporation of fluid viscous dampers as passive additional energy dissipation devices. Because of the inherent nonlinear behaviour of the structures and external devices, a mandatory nonlinear direct integration time-history analysis is performed for all the cases, in which parametric analyses are carried out in order to select the best damper parameters, and for the case of both far-fault and near-fault ground motions. In this part, comparative results are exposed with the aim to propose some practical recommendations.
Abstract
Earthquakes can be really destructive. There is no doubt. Recent seismic events have demonstrated the important effects on structures, and especially on bridges. In this sense, [...]
- 259
- read
Evaluación rápida de la deriva máxima de piso para calcular la vulnerabilidad sísmica de estructuras
R. Aguiar

Monograph Series in Earthquake Engineering, editor A. H. Barbat (2006). MIS57, ISBN: 84-95999-91-9

Abstract
En la última década se han desarrollado importantes investigaciones en los Estados Unidos de Norte América, para evaluar en forma rápida la vulnerabilidad sísmica de las estructuras, a partir del cálculo de la deriva máxima de piso. Estas investigaciones han sido efectuadas en base a sismos registrados fundamentalmente en el área de California y teniendo en cuenta los materiales y sistemas constructivos que ahí utilizan. Para todos es conocido, que la peligrosidad sísmica del Estado de California es diferente de la peligrosidad sísmica de América del Sur y algo similar se puede indicar con respecto a los materiales y sistemas constructivos. Por este motivo es que la Escuela Superior Politécnica del Ejército ESPE, Ecuador, apoyó la realización del proyecto de investigación científica, denominado: “Evaluación rápida de la deriva máxima de piso para evaluar la vulnerabilidad sísmica de estructuras de Hormigón Armado”. En esta investigación se obtienen relaciones entre el desplazamiento máximo inelástico con respecto al desplazamiento máximo elástico, de sistemas de un grado de libertad, pero a partir de sismos registrados en: Colombia, Ecuador, Perú, Argentina y Chile. En ninguno de los países indicados se cuenta con suficientes acelerogramas, de eventos sísmicos cuya aceleración máxima del suelo sea mayor al 10% de la aceleración de la gravedad, que permitan tener una muestra bastante confiable a partir del cual se pueda realizan un estudio estadístico pero al trabajar en conjunto se tuvo 63 registros, que es un número considerable. De igual manera se encuentran relaciones entre la deriva máxima de piso con respecto a la deriva global del edificio pero trabajando con materiales y sistemas estructurales de Ecuador. Para el efecto se han considerado edificios de hormigón armado de uno a seis pisos de alto, conformados por vigas de poco peralte y columnas, sin muros de corte. Este tipo de construcción, que son bastante flexibles, también se las encuentra en países vecinos. Uno de los objetivos de la investigación era mostrar mediante la elaboración de curvas de fragilidad que las construcciones bajas, de uno a seis pisos, que se están realizando en buena parte del Ecuador responden a un nivel de diseño sísmico bajo que no está acorde con la alta peligrosidad sísmica del País caracterizada por una aceleración máxima del suelo en roca del 40% de la aceleración de la gravedad. Se presentan dos metodologías de cálculo para encontrar la deriva máxima de piso, en la que los parámetros que intervienen en su formulación han sido obtenidos en base a registros de Sur América y a sistemas constructivos de Ecuador. La bondad de estas metodologías se ha comprobado, comparando con los resultados que se obtienen del análisis no lineal, paso a paso de más de mil resultados, hallando una muy buena correlación en los resultados medios. En la segunda metodología se halla la deriva máxima de piso, a partir del análisis lineal elástico multiplicando por un parámetro de corrección; esta metodología puede ser aplicable cuando se tengan pocos edificios a evaluar. En cambio la primera metodología que contempla cinco parámetros es aplicable a un gran número de edificios, si se tienen muy pocas estructuras la incertidumbre es alta.
Abstract
En la última década se han desarrollado importantes investigaciones en los Estados Unidos de Norte América, para evaluar en forma rápida la vulnerabilidad [...]
- 1866
- read
Factor de reducción de las fuerzas sísmicas en edificios de hormigón armado sin muros de corte
R. Aguiar

Monograph Series in Earthquake Engineering, editor A. H. Barbat (2007). IS58, ISBN: 978-84-96736-40-7

Abstract
En los Países Desarrollados existen comités de normas que se encuentran trabajando en forma continua, esto se debe a que día a día existen nuevos conocimientos generados por los centros de investigación de las universidades, fundamentalmente. Es así como en estos Países aparecen nuevos códigos cada cierto período regular de tiempo. De tal manera que una normativa o código tiene un número determinado de años de vigencia y luego es obsoleto. Con estas ideas como base y pensando en un futuro Código Ecuatoriano de la Construcción se desarrolló el proyecto: “Factor de reducción de las fuerzas sísmicas”, financiado por la Escuela Politécnica del Ejército. En este proyecto se obtuvo el factor de reducción de las fuerzas sísmicas, con el cual se pasa del Espectro Elástico al Inelástico, en edificios de hormigón armado conformado por vigas y columnas sin muros de corte. Es decir en una sola tipología estructural pero que tiene gran demanda. El objetivo principal fue contribuir a una futura Normativa Sísmica de Ecuador, contribuir a quienes están estudiando y calculando edificios en Ibero América, para que conozcan la parte cuantitativa del factor de reducción de las fuerzas sísmicas ya que en algunas normativas se presentan los valores de R para algunas tipologías estructurales y muy poco o nada se comentan sobre ellas y esto es muy crítico ya que se puede estar subestimando la acción sísmica por una elección inadecuada del factor R. En este libro se verá que el factor R depende del período de vibración, del tipo se suelo, de la ductilidad local de sus elementos, de la deriva de piso máxima permitida, de la forma como se obtiene esa deriva máxima de piso en el rango no lineal, del índice de estabilidad de piso, de la capacidad de ductilidad, de la sobre resistencia y de la redundancia. Son muchos los factores que están relacionados con R y que deberán ser revisados en futuras normativas sísmicas para que no existan inconsistencias.
Abstract
En los Países Desarrollados existen comités de normas que se encuentran trabajando en forma continua, esto se debe a que día a día existen nuevos [...]
- 64
- read