Scipedia: Documents published in 2020

El transporte marítimo y la intermodalidad como solución a la congestión del tráfico transpirenaico

Jesús Sánchez Pinedo — Mon, 31 Aug 2020 12:31:59 +0200

La Comisión Europea secundada por los gobiernos de los estados integrantes, están registrando un incremento en la tasa de crecimiento del volumen de transporte de mercancías, estimando que para el año 2010 el volumen de intercambios entre países Europeos incluidos los 10 recién accedidos, llegará a incrementos superiores al 80% en volumen. Estas cifras superiores no van a poder ser absorbidos por el camión únicamente, lo que implica plantearse la necesidad de mejorar otras alternativas para asegurar que los flujos de mercancías no se interrumpan. A la congestión del tráfico cuyas consecuencias en el crecimiento económico empiezan a entenderse, se deben de sumar las repercusiones medio ambientales, ya que está ampliamente documentado el hecho de que el transporte ferroviario o aún más el marítimo, consume y por tanto contamina menos por unidad de carga que el camión.

El caso de España tiene una lectura múltiple puesto que, se halla en una situación periférica respecto del centro fabril y de consumo Europeo, es zona de tránsito para la mercancía con destino u origen en Portugal, la economía Española ha sufrido un crecimiento continuo de intercambios comerciales con el resto de Europa desde su adhesión a la UE y ello conlleva un gran volumen de bienes, que se canalizan principalmente por la frontera Franco-Española, parcialmente impermeable a causa del obstáculo natural que son los Pirineos. Atendiendo a esta situación un grupo de investigadores del Departamento de Ciencias e Ingeniería Náuticas de la Universidad Politécnica de Catalunya - UPC, se encuentra desarrollando un proyecto de investigación que debe de establecer criterios que permitan evaluar la conveniencia y condiciones para poder desviar de manera efectiva una parte delos flujos de mercancías que actualmente se transportan en camión por los Pirineos, por la opción del ferrocarril o la marítima.

El proyecto INECEU y la problemática del transporte de mercancías desde España a Europa y viceversa

Jesús Sánchez Pinedo — Mon, 31 Aug 2020 11:50:46 +0200

El presente texto, tiene su origen en los estudios y análisis realizaos a cabo dentro del proyecto INECEU (Intermodalidad entre España y Europa), llevado a cabo por un grupo de investigadores integrantes del Grupo de Investigación TRANSMAR, del Departamento de Ciencias e Ingeniería, Náuticas de la Universidad Politécnica de Catalunya. El Ministerio de Fomento ha sido la parte financiadora e interesada en los resultados de este proyecto, dada la importancia de la fluidez del transporte para la economía Española en el contexto Europeo y asimismo debido también a la sensibilidad y voluntad política, de promocionar el transporte marítimo de corta distancia y cabotaje en Europa. El objetivo principal del proyecto INECEU, que parte del análisis de la situación actual en el ámbito del transporte y en concreto de la exportación e importación de cargas unitizadas desde España, es la justificación de unos criterios que una vez aplicados, consigan un desplazamiento más rápido y eficiente de las mercancías, descongestionando las carreteras tras seleccionar los medios más idóneos de transporte, ya sean terrestres como el ferrocarril o la vía marítima y evaluando la idoneidad de utilizar buques de alta velocidad, para reducir en tiempo el tramo puramente marítimo.

La política europea de transporte marítimo y la problemátia de los puertos de refugio

Jesús Sánchez Pinedo — Mon, 31 Aug 2020 11:27:59 +0200

La instauración del Mercado Común Europeo, el 1º de Enero de 1993, abre una nueva realidad a los intercambios comerciales intracomunitarios, realidad que va a requerir de la conformación de infraestructuras de transporte genuinamente transeuropeas que permitan desarrollar un tránsito creciente de bienes y factores productivos en el seno del nuevo espacio europeo. Una pieza fundamental en este proceso lo constituye la modernización y adecuación de las infraestructuras portuarias comunitarias, dada la relevancia que el transporte marítimo posee para el transporte de mercancías intra-europeo. No obstante, la multiplicidad de situaciones en que se encuentran las diferentes instalaciones portuarias europeas supone un verdadero reto para la Política Común de Transporte a la hora de determinar criterios de actuación generales en la financiación de las actividades portuarias. En esta investigación se desarrolla un análisis de la situación asociada a dicho sector a escala europea, así como de las propuestas que se derivan del nuevo impulso relativo a las propuestas que emanan de la propia Política Común de Transportes a este respecto.

Meteorología aplicada a la navegación

Jesús Sánchez Pinedo — Mon, 31 Aug 2020 11:20:57 +0200

El presente libro pretende ser fundamentalmente una herramienta de trabajo para los alumnos de la Licenciatura en Náutica y los más avezados de la Diplomatura en Náutica y Transporte Marítimo de las facultades y escuelas superiores de la Marina Civil de habla hispana. La obra se inicia con un breve repaso al capítulo energético que provee de energía a la atmósfera y que constituye la base combustible de la maquinaria meteorológica. Posteriormente se repasan someramente los criterios de estabilidad del aire, que justifican la formación de centros de presión y la formación de nubes. Tras sentar estas bases, se presenta la circulación general atmosférica y sus consecuencias, así como el papel del viento como igualador de los desequilibrios atmosféricos. Al tratarse de una obra dirigida a los estudiantes de náutica, se relaciona el viento con la formación de las olas. Se distinguen los conceptos de meteorología y climatología, y se analiza el instrumental utilizado en la observación meteorológica. A continuación se aborda la cuestión de la observación y la predicción, que quizás sea la parte que el observador a bordo más necesitaba ver compendiada y que tenía que consultar en otras publicaciones quizá de más rigor científico, pero dirigidas a otro público. Finalmente, se introducen los sistemas usuales de consulta del tiempo por parte del marino, y la obra concluye con un ejemplo de interpretación del parte del tiempo.

Freight cargo crossing the Pyrenees. A chance for short sea shipping

Jesús Sánchez Pinedo — Mon, 31 Aug 2020 10:54:47 +0200

- Around 45% of European Union foreign trade, is still carried by road and is consequently, conditioned by congested traffic, safety risk or high power consumption among other disadvantages, while only 40% is carried by sea by means of the short sea shippong formula. Short Sea Shipping in European waters has been considered by the national and European govermments, as one the most feasible way to discharge the every day more congested roads and higways across Europe. This paper reflects the poses criteria providing recommendations for the best alternative transport mean to truck for the cargo crossing the Pyrenees.

Paquetes Erika I-II, retirada de buques petroleros de casco sencillo de la flota española

Jesús Sánchez Pinedo — Mon, 31 Aug 2020 10:41:45 +0200

- El presente artículo presenta el proyecto fin de carrera de la diplomada en naútica Aurora Segura Ceña, en el cual se realizó una evaluaciín del alcance que en la flota petrolera de pabellón español tendría la normativa europea, integrada por los paquetes legislativos Erika I y Erika II. Haciendo especial hincapié en la introducción acelerada de la normativa en materia del doble casco o diseño equivalente para petroleros de casco único. Dichos paquetes emplazan a un nuevo estatus en la composición de la flota con pabellón de los países de la Unión Europea.

Análisis de los medios de contención para mitigar daños sobre el litoral español atendiendo al actual cambio climatico

Jesús Sánchez Pinedo — Mon, 31 Aug 2020 10:34:51 +0200

El siguiente artículo presenta la esencia del trabajo fin de carrera del diplomado en navegación marítima Manuel Rodríguez Nuevo, el cual pretende abordar la problemática de los daños colaterales que los gases con efecto invernadero están causando sobre el planeta, es decir el cambio climático que está desearrollándose a nivel global y que en un tanto por ciento muy elevado está provocado por el hombre por un consumo de combustibles fósiles. No olvidemos que aunque se cesaron los consumos de estos combustibles en favor de las energías renovables, el ciclo evolutivo de los gases emitidos a la atmósfera continuaría su acción a lo largo de varias centenas de años. Estos daños están catalogados como "fenómenos a largo plazo" pero hoy día ya comienzan a hacer estragos sobre el planeta; subida de las temperaturas, cambios en el nivel del mar, erosiones en las costas y un sinfín de fenómenos metereológicos locales, como tormentas torrenciales, sequías, inundaciones, etc..El planeta se calienta, el nivel del mar sube, las costas retroceden y ante este panorama desolador se siguen firmando tratados que se inclumplen reiteradamente, o que en caso de se aprobados permiten a los países más desarrollados comprar su derecho a contaminar, aunque si bien es cireto que no podemos solucionar el problema globalmente si existe una solución que pasa irremisiblemente por minimizar la erosión de nuestras costea y litorales utilizando los conocimientos que la ingeniería nos proporciona para la construcción de distintos medios de protección.

Incidencia de la altura de las olas en las rutas de navegación de corta distancia en el Mediterráneo

Jesús Sánchez Pinedo — Mon, 31 Aug 2020 10:09:13 +0200

Según la reciente reseña de medio plazo del libro blanco de la UE sobre el transporte, se espera que la navegación de corta distancia en aguas de la UE crezca del 2000 al 2020 en un 59% en volumen (toneladas métricas). Si tenemos en cuenta que el crecimiento global esperado en intercambios de carga es de un 50% (también en volumen), el transporte marítimo es uno de los medios más factibles para reducir la congestión de tráfico en las rutas europeas. Los barcos de alta velocidad son posiblemente un medio que puede competir con los transportes de carretera en algunos determinados tránsitos; sin embargo, estos barcos se ven afectados por el tiempoi nclemente. Este documento analizará la influencia del tiempo en algunas rutas de navegación mediterráneas de corta distancia recorridas por barcos rápidos.

Aplicación de los grafos en la navegación marina

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 14:45:40 +0200

- El presente artículo describe el análisis de viabilidad de la aplicación del concepto matemático de grafo al problema de optimizar derrotas, no solamente en distancia (cálculo analítico directo) sino considerando factores externos variables como vientos, oleaje, hielos o peligros para la navegación, que pueden influir en la elección final del trazado del rumbo del buque. El trabajo realizado detrás de esta muestra que es el artículo, se halla en la tesina de licenciatura realizada por el primer autor y dirigida por el segundo.

Brief analysis on the generated residues coming from oil sea transport in Spain

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 14:32:36 +0200

Around 1.500 to 1.800 million tonnes of crude oil and over 400 to 500 millions of tonnes of refined oils ; are transported across the sea every year on board tanker ships. Europe is a great consumer of those commodities, receiving up to 500 millions of crude oil tonnes and around 250 to 300 million of refined products tonne per year. This means that EU needs about 6000 freights per year in order to covr the crude oil demand, carried out by between 155 to 2000 tanker ships. This paper is going to analyse the residues generation coming from such exchanges in the Spanish waters.

Modelo de formulación para comprender los costes y tiempos de los acarreos terrestres para el reparto de mercancías mediante transporte rodado de mercancías y transporte marítimo de corta distancia

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 14:08:06 +0200

- En el desarrollo del mundo globalizado cada vez resulta de mayor importancia cómo se distribuyen las mercancías desde su origen a su destino. Es cierto que la tendencia y la conciencia tiende a realizar transportes más respetuoso con el medio ambiente y más eficientes. En muchas ocasiones nos encontramos con la ilógica situación de contratar transportes sin un criterio razonado. El propósito de este artículo es plantear la realización de un simulador de costes y tiempos para valorar la posibilidad de llevar a cabo un transporte de mercancías con el modo más acertado, sabiendo de antemano cual será su coste y su precio. Debemos entender que el modo de transporte de carretera es necesario e incluso imprescindible, pero en muchos de los escenarios no es el más conveniente. Planteamos por tanto, la realización de un transporte multimodal e incorporar en el mismo el TMCD (Transporte Marítimo de Corta Distancia)

A study of the riskiest points in front of an oil slick due to an accident in the spanish mediterranean coast

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 13:59:59 +0200

Pollution from shipping traffic poses a real risk to the Spanish coast. Memories of the Fedra bulk carrier disaster in the Strait of Gibraltar, the Prestige sinking in Finisterre or the Castor near accident off Almeria coast are still fresh. The main objective of this paper is to analyse, identify and quantify the Spanish Mediterranean coastal areas where spills from tankers are most likely to occur. The article based on a study which uses a set of variables such as geographical peculiarlities, climate, ship age and traffic density to feed an algorithm. This objective function weighs these parameters all along the coast and identifies the Spanish coastal areas having the highest risk of spills.

Cost assessment simulator for transport between mediterranean Spanish ports and the Black Sea

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 13:41:13 +0200

There is a strong imbalance in EU transport mode shares. In addition, issues like road traffic, noise, accident rates, and especially polluting emissions result not only in external costs to society, but also in high logistical costs to transport service customers. The present paper proposes an assessment model to evaluate final internal and external costs of transport chains served by trucks and short sea shipping (SSS). An efficient and fast tool is presented to help customers decide on the most convenient mode of transportation for a specific trade link. The trade links in this paper connect 19 Spanish provinces to the main ports in the Black Sea region (Bulgaria, Georgia, Romania, Russia, Turkey, and Ukraine) through the ports of Barcelona and Valencia.

Analysis of viability to promote a hub ro/ro terminal in Palma of Mallorca (Spain) port

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 13:28:44 +0200

The presented paper is going to analyze the opportunity to develop a Ro/Ro hub in the Port of Palma de Mallorca.

In order to get introduced in the study, the state of art related to geographical, economic traffic and human; conditions, will be reviewed: together with an in deep analysis of the port future capacities and main shipping lines crossing the western Mediterranean. At a first glance is it easy to understand that the competition with other container hub ports in Mediterranean does not afford Palma de Mallorca to be positioned in this market. But the chance to become a hub in rolled traffic will be studied.

The final results of this paper are going to identify the main particulars to be enforced to attract the main shipping companies are providing transport services between the North and South coasts of the Mediterranean and the traffic between Italy and Spain.

The Exploration, Development and Perspective of Oil And Gas in The Black Sea Region

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 13:18:09 +0200

The Black Sea region, a large horizon ready to open, ready to explore, ready to show her energy, her power and opportunities. But how we are preparing for this?. It is a high compettiton between all the actors implicated in this field.

The industry was informed to this potential resources by a major study undertaken by Purvin and Gertz in 2011, which predicted a development of a Romanian offshore industry and now exist many recently studies that confirmed the resources of the Black Sea.

We all nnow about the emergence of shale gas in europe, in the last years because is increasing evidence os a more united approach on energy, so the exploration and development of gas reserves in the Black Sea is an optimal alternative to supply gas from the Caspian to South-Eastern Europe.

But this good alternative implicates problems generated by costs, transportation and security of the very long pipelines that will pass through several countries till reaching their final destination.

We try in this paper to pay attention on the main objective in the Black Sea region, in this offshore field, that required the cooperation and sustainability from part of European Union and all its members' state and countries situated in the Black Sea, Mediterranean Sea or Caspian Sea.

A Ship Routing System Applied at Short Sea Distances

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 12:59:45 +0200

New generation of high-resolution meteo-oceanographic predictions provides useful tools for routing of ships in short maritime distances. In this work, the optimal ship routing analysis is investigated in maritime routes in the Western Mediterranean Sea for relative short sea distances. A* algorithm is implemented in order to obtain the optimal path under an energetic wave events. The methodological aspects are presented including the grid description and weather prediction systems. The optimized cost function is the travel time and it is obtained considering the added resistance due to waves. A practical example considers the maritime route between Barcelona and Algiers. The results show the influence of this factor in the optimum path recovered by the algorithm. The relevance of the relative direction between wave and ship route is proven comparing the ship routing results.

Alternative Manoeuvres to Reduce Ship Scour

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 12:43:36 +0200

Scouring and sedimentation effects on the seabed induced by ship propellers during ship manoeuvring near harbour structures affect both structure stability and ship manoeuvring capabilities. This contribution proposes solutions at an operational level using the automatic identification system (AIS) and a bridge simulator. Two new alternative manoeuvres were designed and tested on a bridge simulator to obtain expected maximum scour depth and the results were compared with that of real manoeuvres (i) using mooring lines, and (ii) with tug assistance. A total of 42 test scenarios combining several manoeuvres and meteorological conditions were reproduced. Results confirmed a clear reduction in erosion depth with the alternative manoeuvres, with total reduction when using the tugboat. The presented methodology can be very useful to port authorities to prevent the effects of ship erosion on harbour infrastructures.

IoT-Driven Business Model Innovation: A Case-Study on the Port of Barcelona in the Context of the Belt and Road Initiative

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 12:36:40 +0200

During the last decade, new technologies have pushed organizations to innovate their business models. In particular, Industry 4.0 and the Internet of things (IoT) have called for their own business models, in order for them to live up to their potential as sources of value and revenues. Seaports have not been alien to this trend. As key nodes in the global supply chain and logistic networks, some of them have evolved towards a new value-generating and community-focused model, categorized as the fifth generation (5G) port. This research paper explores what impact does IoT technology will likely have in the evolution of seaports business models, as well as the role that institutional initiatives play in such evolution. To do so, a case-study is presented about the Port of Barcelona, and the strategic policies that it has adopted in the context of the Belt and Road Initiative developed by the Chinese government. The case shows, though not conclusively, a relationship between IoT technology and the adoption of a 5G business model.

Stern Twin-Propeller Effects on Harbor Infrastructures. Experimental Analysis

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 12:30:10 +0200

The growth of marine traffic in harbors, and the subsequent increase in vessel and propulsion system sizes, produces three linked problems at the harbor basin area: (i) higher erosion rates damaging docking structures; (ii) sedimentation areas reducing the total depth; (iii) resuspension of contaminated materials deposited at the seabed. The published literature demonstrates that there are no formulations for twin stern propellers to compute the maximum scouring depth. Another important limitation is the fact that the formulations proposed only use one type of maneuvering during the experimental campaign, assuming that vessels are constantly being undocked. Trying to reproduce the real arrival and departure maneuvers, 24 different tests were conducted at an experimental laboratory in a medium-scale water tank using a twin propeller model to estimate the consequences and the maximum scouring depth produced by stern propellers during the backward/docking and forward/undocking scenarios. Results confirm that the combination of backward and forward scenario differs substantially from the experiments performed so far in the literature using only an accumulative forward scenario, yielding deeper scouring holes at the harbor basin area. The results presented in this paper can be used as guidelines to estimate the effects of regular vessels at their particular docking location.

Potential economic benefits of using a weather ship routing system at Short Sea Shipping

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 11:47:37 +0200

This contribution investigates the economic benefits of using weather ship routing on Short Sea Shipping (SSS) activities. The investigation is supported with the development of a ship routing system based on pathfinding algorithm, the parametrization of the wave effect on navigation, and the use of high-resolution meteo-oceanographic predictions. The optimal ship routing analysis is investigated in a European SSS system: the link between Spanish and Italian ports. The results show the economic benefits using ship routing in SSS during energetic wave episodes. The rate of cost savings may reach 18% of the total costs under particular bad weather conditions in the navigation area. The work establishes the basis of further developments in optimal route applied in relatively short distances and its systematic use in the SSS maritime industry.

Ship weather routing using pathfinding algorithms: the case of Barcelona – Palma de Mallorca

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 11:32:09 +0200

Weather ship routing has become a recognized measure to target safe, sustainable and economical ship activities. Academic research has focused the ship routing optimization through pathfinding algorithms which take into account the meteo-oceanographic forecasts (i.e. wind, waves or currents predictions). This contribution shows the results of the numerical simulations carried out during the development of a weather ship routing applied to a ferry service in the Mediterranean Sea: Barcelona – Palma de Mallorca. From a methodological point of view, the pathfinding A* algorithm is applied to optimize the travel time considering the wave action. Under severe weather conditions, a reduction of the 7% of the travel time is obtained comparing the optimized route and the minimum distance route. The results show also a non-significant correlation between the travel time reduction and wave height. In consequence the benefit of ship routing depends not only of the wave height but also in the spatial sequence of the storm.

Tools for Evaluation Quay Toe Scouring Induced by Vessel Propellers in Harbour Basins During the Docking and Undocking Manoeuvring: Marine Navigation and Safety of Sea Transportation

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 11:15:48 +0200

The evolution of the shipping industry (increased capacity and size of ships, power and self-propulsion), the increased productivity and rearrangement of spaces (port calls increased in number and frequency, changes in use of docks), the intensification of the use not only of stem main propellers (conventional or azimuthal) but also lateral bow and stem ones, are the leading causes of injury to the toe of the docks. Scouring processes due to manoeuvring actions can produce big consequences on the stability of harbour structures such as docks and protecting dikes. As a consequence, the sedimentation of the eroded sediment reduces the total depth of the harbour basin and navigation channel. At the same time, contaminants settled at the bed of the harbour basins may be resuspended by the effect of vessel’s propellers and produce an important environmental problem to harbour authorities.

One of the main problems is the interpretation of parameters related to propellers, but also the fact of not considering important aspects such as different types of propeller, manoeuvring practices for docking and undocking, propulsion system orientation or the confinement effect generated by the dock itself and the shelter of the vessel. This contribution aims to assess docking and undocking manoeuvres which can produce erosion generated by the propulsion of ships. This methodology will analyse manoeuvres patterns and will allow understanding the effects of the sedimentation of the eroded sediment on docking and undocking manoeuvres.

The application of route planning in a Maritime Spatial context. Its applicatoion in the Balearic Islands

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 10:53:17 +0200

The sea is home of a large variety of human activities creating social, economic and even strategic value for Europe’s inhabitants. Maritime activities have been concentrated around fishing, defence and shipping, although other human activities are increasingly taking place in marine areas. Some of those new activities have been growing substantially creating significant value for Europe’s maritime economy. Governments are aware of the need to better and more coherently management of seas in the European Union, being the Integrated Maritime Policy an umbrella for this approach. Maritime Spatial Planning is defined as a process of analyzing and allocating the spatial and temporal distribution of human activities in marine areas to achieve ecological, economic and social objectives. The Mediterranean Sea as a vast area covering twenty-two states from three continents, is an scenario where an increasing number of stakeholders have become aware of the urgency to find the right balance between economic benefits and (in their relation with the environment) the use of maritime space. The presented paper is going to apply the route planning in the short sea traffics linking peninsula with the Balearic Islands within a Maritime Spatial Planning scenario and evaluating their environmental performances. Some proposals will be suggested for a better coexistence between the maritime traffic and the protection of environmental sensitive areas.

The Prevailing Weather and Traffic Conditions in the Evaluation of a Future ECA in the Mediterranean Sea. A view into the Western Mediterranean

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 10:46:19 +0200

Appendix III of MARPOL's Annex VI sets out the criteria and procedures for designating an emission control area (ECA).These criteria includes: a clear delineation of the proposed ECA; types of emissions proposed for control, land and sea areas at risk; emission quantification and impact assessment; prevailing weather conditions; data and quality on marine traffic; land based measures concurrent with the ECA adoption and the relative costs of reducing emissions from ships. This paper analyses the climate parameter together with traffic conditions: prevailing weather conditions as a parameter to be kept in mind for the adoption of a future ECA in the Mediterranean Sea. Preliminary results would show how marine emissions coming from existing traffic will impact the sea and land ecology in the Mediterranean area.

Manoeuvring and hotelling external costs: enough for alternative energy sources?

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 10:29:52 +0200

Local air pollution is the most relevant externality of maritime transport, and its effects are more acute in urban areas as a result of manoeuvring, hotelling and load/unload activities at ports. This article is intended to assess ships’ local air pollution impact in generally densely populated harbour areas to decide whether alternative power supply measures are feasible. First, an optimized infrastructure investment model is developed to ease implementation and maximize the efficiency of alternative power supply projects. Once target harbours and traffic (ship types) within a national port network have been chosen, a vessel traffic analysis (ship type, tonnage, manoeuvring, and hotelling times) is carried out to quantify and evaluate annual polluting emissions (PM2,5, SO2, NOx, and VOCs) and their externalities. Finally, the assessment model is applied and results of the Spanish port network case study are discussed. The results obtained are significant and bring the possibility of further controlling the ship’s environmental performance at berth.

SHIPPOL, towards an Automatic Green House Effect Gases Tracing and Accounting System in Harbour Areas by Using AIS Technology

Jesús Sánchez Pinedo — Fri, 28 Aug 2020 10:02:24 +0200

Identification, tracing and monitoring of ships have been widely exploited by means of the Automatic Identification System (AIS). Considerable improvements in safety, collision avoidance and vessel traffic services operations (VTS) have been reached since the system was mandatory in 2002 and applied to ships built on or after 1 July 2002 and to ships engaged on international voyages constructed before 1 July 20021. Nevertheless, the possibility to storage, exchange and exploit dynamic and static information, for other reasons different to those mentioned above, can result in complementary associated phenomena analysis in shipping industry. Because of the possibility to observe and identify a vessel in a specific place and time, dynamic parameters like speed and position can be linked to the identification vessel data services in order to compute real time fuel consumption and therefore, the volume of pollutant gases emissions, providing more precise air pollutants emissions accounting different than the fuel consumption declarations. With this assumption, we have proposed a model which applies identification and speed information from AIS, and in consequence, the type of engines operating during the voyage, extracting data from public EQUASIS databases. With the help of Geographic Information Systems (GIS), real time and dynamic air pollution data can be computed and mapped in congested waters. Critical infrastructures like ports and its surroundings need other kind of data treatment because of the manoeuvring operations during berthing or piloting, most of them under different consumption conditions in the main engines. The present paper shows our first steps in analysing a suitable mathematical model which fits the three components (earth observation, communications and navigation satellite, airborne and land data acquisition) in air pollution from shipping dynamic mapping. This is our first step to approach to an Automatic Green House Effect Gases Tracing and Accounting System.

A Simulation Model for Road and Maritime Environmental Performance Assessment

Jesús Sánchez Pinedo — Thu, 27 Aug 2020 14:34:03 +0200

The White Paper published in 2011, Roadmap to a Single European Transport Area [1], urges on a 30% modal shift of road freight over 300 km to other modes (rail, maritime and inland waterways) by 2030, and more than 50% by 2050. However the environmentally friendly performance of maritime transport regarding air pollutant emissions in comparison with road transport is in doubt. This paper presents a three dimension simulation model, in which performed transport work, arisen emissions and produced impact are estimated and inter-related for the assessment of the environmental performance of both road and maritime transport. The simulation model will be a valuable decision making tool for policymakers as it enables the precise assessment of considered transport alternatives in the EU27 until 2020, and hence supports the design of future intervening actions.

Speeds & Capacities Necessity of Boats for Improve the Competitiveness of the Short-Sea-Shipping in West Europe Respecting the Marine Environment

Jesús Sánchez Pinedo — Thu, 27 Aug 2020 14:15:53 +0200

- This paper aims to contribute to highlight the main factors which determine the commercial success of Short-Sea-Shipping lines. As a part of complex topic of modal competition, we will focus on the ship's performances. The finality is to define the capacities and the speeds needed by ships for compete effectively with the services "all-by-road" of freight transport in West Europe. In fact, the flexibility is the main competitive advantage of road transport over the other modes as maritime, fluvial or railways, and the travel time is the second one. With exception of some cases which have ports as origin and destination, the transport “Door-to-Door” needs the participation of road transport ineluctably. So, the modal competition between the Short-Sea-Shipping and the road transport is in fact a problem of their complementarily. The really important matter is how to maximize the Short-Sea-Shipping' component into the travels which combine the maritime and the road transports. The main impediments for the SSS's component maximisation are the travel time of the boats and the ports passage time.In continuity of our precedent researches, we use the results showing the more competitive SSS's lines (Martell Flores, 2007). On this base, we proposed the links between ports and the best operation way for each one, in “classical lines” of collecting & distribution or as "shuttle lines". All lines initially proposed are competitive with road transport under the costs criterion, but not always, even rarely, under the travel time criterion. We take the travel time by road as reference to define the travel time that the ships need to reach in order to be competitive. So, this analysis includes the cost & the travel time as criteria of comparison. We analyzed a network of the main 112 cities in West Europe, including 57 ports, which constitute our O-D matrix. For this analyse we use the DETCCM algorithm, it identified the differences between travel times of transports in “all-by-road” and in combined “maritime / road” for each possible link of the O-D matrix. The results show us a selected number of SSS's lines which are competitive in the current conditions of travel time. They show us the average speeds' necessaries to reach the competitive travel times for the rest of the lines. Finally, we made a performances’ review of the more currents ships in order to propose the more adapted kind of ship to the SSS proposed lines. The results underline the necessity to make new naval engineering developments oriented to design a specific Short-Sea-Shipping' boat in the close future.

Analysis of the prevailing weather conditions criteria to evaluate the adoption of a future ECA in the Mediterranean Sea

Jesús Sánchez Pinedo — Thu, 27 Aug 2020 14:03:25 +0200

Appendix III of MARPOL's Annex VI sets out the criteria and procedures for designating an emission control area (ECA).This criteria includes: a clear delineation of the proposed ECA; land and sea areas at risk; emission quantification and impact assessment; prevailing weather conditions; data on marine traffic; and land based measures concurrent with the ECA adoption. This paper analyses one of these parameters: prevailing weather conditions to evaluate the adoption of a future ECA in the Mediterranean Sea. Results will demonstrate how marine emissions will impact the sea and land ecology in the Mediterranean area.

Road and Maritime Transport Environmental Performance: Short Sea Shipping Vs Road Transport

Jesús Sánchez Pinedo — Thu, 27 Aug 2020 13:58:33 +0200

Motorways of the Sea (MoS) are part of the European transport strategy towards an efficient, safe and environmentally friendly transport system. This paper develops a model for short sea shipping (SSS) and road transport environmental performance comparison, estimating direct emissions and quantifying their impacts due to air pollutant and greenhouse (GHG) gas emissions. Ultimately a case study is presented to analyse and valuate each transport alternative to design an action plan determining intervening actions favouring the rebalance of the current transport system.

Implementación CGPS y altimetría en los Puertos de Ibiza, l'Estartit y Barcelona para monitorización del nivel del mar

Jesús Sánchez Pinedo — Thu, 27 Aug 2020 13:52:55 +0200

Dos campañas aéreas con el LIDAR Optech ALTM-3025 del ICC (Instituto Cartogáfico de Cataluña) fueron realizadas el 16 de Junio de 2007 de día con un Partenavia P-68 y el 12 de Octubre de 2007 de noche con un Cessna Caravan 208B. La validación posible de esta nueva tecnología LIDAR puede ser útil para suministrar medidas en áreas costeras, de unos 15 a 20 km desde la línea de costa, donde la altimetría radar por satélite da problemas severos debido al amplio haz («footprint») que abarca zona de tierra. La segunda campaña aerotransportada se realizó coincidiendo con el paso del satélite ICESat provisto de un láser altímetro. Se describe la situación actual de las infraestructuras CGPS en Ibiza, l'Estartit y Barcelona así como sus aplicaciones a la monitorización del nivel del mar y calibración altimétrica. El objetivo principal es la integración de datos geodésicos espaciales, aerotransportados e in-situ para establecer áreas de calibración altimétrica en el Mediterráneo Occidental en el marco del estudio del Cambio Global.

Is the utilization of methane gas the solution to air pollution in diffuse sectors? The case of Port of Castellón

Jesús Sánchez Pinedo — Thu, 27 Aug 2020 13:43:13 +0200

Considering environmental regulations, imposed by an international regulation body restricting the emission levels from ships in ports, with even more stringent local regulations envisaged, the challenges for the world’s fleet are not only technical but economic and logistical. On the one hand, there are different technical alternatives enabling the current international regulations to be met. Even avoiding on board modifications,the owner can decide to use low sulphur content fuels, together with slight changes in engines to reduce the levels of nitrogen oxides. But the question posed in this paper is how to support the decision to use high quality oil derivatives, bearing in mind environmental considerations, but with a favourable economic balance. That enormous cost will be translated into a higher transport chain cost. Additionally, regarding coastal navigation, it might become possible for some new regulations to penalize elevated rates of CO2 emissions, not yet considered by the MARPOL convention. This paper analyzes the availability of the use of methane as an ideal fuel which meets the nowadays and even future, local and international regulations on CO2 and NOx, regarding the fuel derivatives and no emissions of sulphur oxides and ashes.

Port-City Closeness and Turnaround Time Critical for Short Sea Shipping Sustainable Performance a Case Study: Spain

Jesús Sánchez Pinedo — Thu, 27 Aug 2020 13:31:32 +0200

Air pollution is the most relevant externality of maritime transport and its effects are more acute in urban areas. As Short Sea Shipping (SSS) services call ports frequently and expend significant time in port, both the overall turnaround time and the port city closeness, become critical in their sustainable performance. This paper analyses the impact of maritime transport on Spanish SSS ports and identifies the ideal ones, reflecting the differences in their sustainable performance and finally identifying the characteristics that a harbour needs to gather in order to minimize air pollution impact in the maritime transport sector.

"e" un nuevo paradigma en la navegación y el transporte marítimo: "electronic-enhanced-environmental"

Jesús Sánchez Pinedo — Thu, 27 Aug 2020 13:24:10 +0200

En la era digital y de la información, el mundo del transporte marítimo ha tenido que adaptarse al uso de las tecnologías de la sociedad de la información y las comunicaciones, casi todas, “bautizadas” con el sello “e”. Como se irá argumentando, la “e” puede tener un significado según el contexto pero a la postre, permite interpretarse como un elemento integrador que emplea algún atributo de naturaleza electrónica o digital y que se traduce en la adopción de sistemas y servicios más robustos que optimizan el uso de recursos, tiempo y obviamente, costes, en los procedimientos de adquisición, intercambio, visualización, envío y actualización de datos, imprescindibles en cada uno de los ámbitos y procedimientos involucrados en el transporte de mercancías y pasajeros por mar. Mediante este artículo se buscará ubicar a la Industria Marítima Española dentro de estas tendencias y la implantación de conceptos como ventanilla única, interoperabilidad,gestión de los flujos de información y otros más, asociados a una dinámica “estandarizadora” y “armonizada” dentro del contexto europeo del Transporte de Superficie y más concretamente, los corredores marítimos y multimodales que han de 1 conformar lo que se ha denominado “Autopistas del Mar”

¿Riesgo de mareas negras procedentes del mar abierto?

Jesús Sánchez Pinedo — Thu, 27 Aug 2020 13:05:01 +0200

El objetivo fundamental de este artículo es el de analizar, identificar y, posteriormente, cuantificar las áreas de la costa Española Mediterránea con mayor riesgo de sufrir un derrame de hidrocarburos procedente del tráfico marítimo de hidrocarburos. En el estudio que fundamenta este artículo se han tomado en consideración una serie de variables de entre las que destacamos las peculiaridades geográficas, climáticas o la densidad de tráfico que alimenten una función aleatoria. Esta función objetiva ponderará los diferentes puntos de la costa e identificará los que tengan una mayor probabilidad de riesgo.

En la investigación aquí presentada se presente evidenciar dónde pueden ubicarse las áreas del Mediterráneo Occidental español con mayor riesgo potencial de marea negra procedente de derrames de hidrocarburos.

Una propuesta de ecobono español

Jesús Sánchez Pinedo — Thu, 27 Aug 2020 11:58:02 +0200

El presente estudio, fue financiado en la convocatoria del año 2008 según ORDEN FOM/2219/2008, de 22 de julio (BOE del 29), de subvenciones para la realización de estudios y acciones de difusión relacionados con el transporte, sus infraestructuras y demás competencias del Ministerio de Fomento. El objeto del mismo fue la elaboración de un análisis comparativo entre los costes externos generados por el transporte por carretera y el marítimo en un mismo recorrido. De esta comparativa se dedujo en cada caso una diferencia entre los costes externos producidos por cada modo de transporte. En el caso que esa diferencia en costes externos fuera favorable al transporte marítimo, los autores proponen una subvención a los transportistas que usen el modo marítimo, con un tope igual a ese diferencial citado pro recorrido y camión. Postprint (published version)

Sustainability of motorways of the sea and fast ships

Jesús Sánchez Pinedo — Thu, 27 Aug 2020 11:24:57 +0200

The European transport policy undertakes to enhance sustainability in transport in order to boost economic activities in the whole EU. The reduction of pollutant emissions and a better balance among modes of transportation to cut road congestion are the pillars of the above policy. These factors are encouraging public and private stakeholders to use the freight maritime alternative more extensively. Short sea shipping is considered the quickest way to reach sustainability. Another advantage of ships over trucks and trains is that vessels consume less fuel as a result of the relatively low speeds at which they travel. However, increasingly faster ships are in a position to compete with trucks, but the former’s greater power demand and consumption rate result in higher pollutant emission levels which, in turn, lead to the loss of their environmental advantage over road transport. This problem is analyzed below.

Análisis medioambiental de la eficacia del transporte marítimo de corta distancia en las cadenas de transporte intermodal

Jesús Sánchez Pinedo — Thu, 27 Aug 2020 11:02:50 +0200

El presente articulo describe un prototipo de un sistema de adquisicion de videos o el el siguiente articulo presenta la esencia del trabajo fin de master del ingeniero en logistica, transporte y movilidad, Manuel Rodriguez Nuevo, el cual pretende evaluar los costes y externalidades medioambientales entre los modos d transportes por carretera y por vnia maritima. La creacion de una ruta que gestiona el comercio entre el puerto de Tarragona (Espana) y los de Patras (Grecia) e Izmir (Turquia)

Selection of Short sea Shipping Transport Chains in Western Europe, Based on External Costs

Jesús Sánchez Pinedo — Thu, 27 Aug 2020 10:55:49 +0200

According to the mid term review of the EU White Paper on Transport, Short Sea Shipping is expected to grow at a rate of 59% in metric tonnes, from 2000 to 2020. If we consider that the overall expected growth in freight exchanges is of 50% (also in volume), sea transport is one of the most feasible way to reduce traffic congestion on European roads. Marine transport is a possible way to compete with road transport in certain traffics, mainly when assuming external costs. This paper is going to analyse five multimodal routes, considering three different levels of powered ships, which one is going to be the most efficient in terms of external costs.

Heavy Weather in European Short Sea Shipping: Its Influence on Selected Routes

Jesús Sánchez Pinedo — Thu, 27 Aug 2020 10:48:04 +0200

According to the mid-term review of the EU White Paper on Transport, short sea shipping is expected to grow at a rate of 59% in metric tonnes, from 2000 to 2020. If we consider that the overall expected growth in freight exchanges is of some 50%, sea transport is one of the most feasible ways to reduce traffic congestion on European roads. High speed vessels are a possible way to compete with road transport on certain routes; however, these ships are highly affected by heavy weather. This paper analyses the weather influence on several short sea shipping routes to be served by fast ships.

The ICARUS portal: An aid to improve safety of navigation

Jesús Sánchez Pinedo — Thu, 27 Aug 2020 10:18:20 +0200

Leisure ships and non SOLAS (International Convention for Safety of Life At Sea) ships as fishing vessels or small tugs, are not subjected to International Maritime Organization (IMO) standards related to the equipment, but by the classification societies through additional requirements related to the control centre physical distribution.

The ICARUS concept tries to provide to the end users, a practical tool supplying information from the books collection on board like Pilot books and others as well as meteorological information and weather forecasting, all integrated in an internet portal, accessible from portable devices like the latest generation mobile phones or palms. GPS or positioning systems will make possible to update information and selected screens will display data required by means of a complete menu. Today communication and internet based technologies with the support of GIS technologies have created a very friendly environment. XML and JAVA technologies have been used for the data interchange and software development in the end user´s application.

Studies of suitability on short sea shipping routes in SW Europe

Jesús Sánchez Pinedo — Thu, 27 Aug 2020 09:53:09 +0200

Around 45% of European Union (EU) foreign trade is carried by road, which is conditioned by traffic congestion and high fuel consumption, and lead to implying the pollution and safety problem. Short Sea Shipping forms another 40% of the EU foreign trade. National and European governments have considered the Short Sea Shipping in European waters as one of the most feasible ways to alleviate the congestion which is getting worse each day on roads and highways in Europe. The main aim of this paper is to both study and identify the feasible routes in SW Europe which appear to be a viable solution for avoid road transport problems.

Wave Height Incidence on Mediterranean Short Sea Shipping Routes

Jesús Sánchez Pinedo — Thu, 27 Aug 2020 09:33:24 +0200

According to the recent mid term review of the EU white paper on transport, Short Sea Shipping in EU waters is expected to grow from 2000 to 2020 at a rate of 59% in volume (metric tonnes). If we consider that the overall expected growth in freight exchanges is of 50% (also in volume), sea transport is one of the most feasible ways to reduce traffic congestion on European roads. High speed vessels are a possible way to compete with road transport in certain traffics; however these ships are highly affected by heavy weather. This paper is going to analyse the weather influence on several short sea shipping Mediterranean routes to be served by fast ships.

Short sea shipping opportunities for the Pyrenean cargo flows

Jesús Sánchez Pinedo — Wed, 26 Aug 2020 14:17:15 +0200

This paper tries to show the results and conclusions reached by a small research team within the TRANSMAR research group of the Nautical Engineering and Sciences department from the Technical University of Catalonia, the research study carried out has been called INECEU (Intermodality between Spain and Europe) and it has been endorsed by the Spanish Ministry of Transport. The main objective of this study was to evaluate the chances for the maritime transport within a multimodal chain, to alleviate the freight road traffic crossing every year the Pyrenean border. In fact, there is well known the limitations of the terrestrial infrastructures, being nowadays supporting a high degree of congestion. Thus the possibility to pass a part of those goods carried by truck to the maritime mode, would help to reduce those highways overloading, and also improving the pollutant particles and gases emissions. In a first instance the transport by sea, is the most efficient in consumption and pollution terms. However its own justification is not dependent only from the sea leg figures in a multimodal chain but from the overall steps by which the cargo loaded on board should pass.

High speed crafts viability analysis

Jesús Sánchez Pinedo — Wed, 26 Aug 2020 14:11:17 +0200

This paper presents a brief analysis on the applicability of high speed crafts in short sea trades, from different marine stakeholders point of view. The TRANSMAR research group of the Nautical Engineering and Sciences department from the Technical University of Catalonia, has continued the finished study (INECEU: Intermodality between Spain and Europe), proposing fast ships for serving some of the selected sea links in West Europe in it. The recent communication regarding the mid-term review of the European Commission's 2001 White paper on Transport, confirms that the evolution of modal split in freight transport from the year 2000 up to the year 2010, will show a steady share of 39% for the waterborne transport and a slight increase in the road transport. One of the four pillars of the European transport policy is the innovation in transport technologies and systems, improving its efficiency and logistics throughout the supply chain.

Selection of Short Sea Shipping transport alternatives in SW Europe

Jesús Sánchez Pinedo — Wed, 26 Aug 2020 13:31:38 +0200

According to the mid term review of the EU White Paper on Transport, Short Sea Shipping is expected to grow at a rate of 59% in metric tonnes, from 2000 to 2020. If we consider that the overall expected growth in freight exchanges is of 50% (also in volume), sea transport is one of the most feasible way to reduce traf-fic congestion on European roads. Marine transport is a possible way to compete with road transport in certain traffics, mainly when assuming external costs. This paper is going to analyse five multimodal routes, considering three different lev-els of powered ships, which one is going to be the most efficient in terms of exter-nal costs.

The external cost of speed at sea: An analysis based on selected short sea shipping routes

Jesús Sánchez Pinedo — Wed, 26 Aug 2020 13:18:15 +0200

According to the mid-term review of the EU White Paper on Transport, Short Sea Shipping (SSS) is expected to grow at a rate of 59% (metric tonnes) between 2000 and 2020. If we consider that the overall expected increase in both freight exchanges and volume is 50%, sea transport is one of the most feasible alternatives to reduce traffic congestion on European roads. Maritime transportation may compete with road transport as far as certain traffics are concerned, but only when assuming external costs. This paper analyzes several intermodal transport chains involving a sea leg by comparing the effect of pollutant emissions from different ship types and road transport in terms of potential external cost savings. The translation of these emissions into environmental costs shows, for certain conditions, savings in the case of sea transport that would justify the use of an environmental bonus to promote the sea option.

Modelo de formulación para comprender los costes y tiempos de los acarreos terrestres para el reparto de mercancías mediante transporte rodado de mercancías y transporte marítimo de corta distancia

Jesús Sánchez Pinedo — Wed, 26 Aug 2020 12:35:51 +0200

En el desarrollo del mundo globalizado cada vez resulta de mayor importancia cómo se distribuyen las mercancías desde su origen a su destino. Es cierto que la tendencia y la conciencia tiende a realizar transportes más respetuoso con el medio ambiente y más eficientes. En muchas ocasiones nos encontramos con la ilógica situación de contratar transportes sin un criterio razonado. El propósito de este artículo es plantear la realización de un simulador de costes y tiempos para valorar la posibilidad de llevar a cabo un transporte de mercancías con el modo más acertado, sabiendo de antemano cual será su coste y su precio. Debemos entender que el modo de transporte de carretera es necesario e incluso imprescindible, pero en muchos de los escenarios no es el más conveniente. Planteamos por tanto, la realización de un transporte multimodal e incorporar en el mismo el TMCD (Transporte Marítimo de Corta Distancia)

Improvement of the energy efficiency of vessels as a measure for the reduction of greenhouses gases emission froem sea shipping

Jesús Sánchez Pinedo — Wed, 26 Aug 2020 11:52:46 +0200

As all we know, pollution is a serious actual problem that affects our society. Maritime transport is responsible of part of that pollution and with this purpose; measure to be taken in the logistical and maritime transport field is to reduce ships emissions. Air pollution is not the only problem, but greenhouse gas emissions too, mainly in the case of maritime transport pollutants as NOx and SOx gasses. This article tries to do a quick view on the last measures took by the International Maritime Organization (IMO) in order to reduce greenhouse gas emissions of shipping. An energy efficiency index for ships was created by the Marine Environment Protection Committee (MEPC) to improve their energy efficiency and then reduce fuel consumption. This index was developed in voluntary interim guidelines established in last sessions of the MEPC among 2009 and 2010, and can be applied to both new designs and ships in operation. Nowadays is just a voluntary measure that whatever ship-owner could take and verify, but until its approval there is for the moment no sanction if the results are not the expected ones by the guidelines. A description of the above mentioned guidelines will be exposed.

Design of a Remote Monitoring System for High Speed Craft

Jesús Sánchez Pinedo — Wed, 26 Aug 2020 10:16:24 +0200

At present, the whole shipping industry is concerned about safety of navigation. In particular, attention is focused on High Speed Craft. There has been a sharp increase in numbers of this kind of vessel, which primarily carries passengers but is also known to carry goods. Some units can reach speeds of over 45 knots with capacity for 900 passengers. These passengers have a basic right to life and their means of transport should obviously follow all safety codes, regulations and IMO resolutions. This paper describes the development of a monitoring system that could automatically transmit safety parameters and position from the ship to a management control centre. Digital and analogical alarms, ship condition readings and other safety-related parameters may be recorded and transmitted in near real- time using the latest communications and positioning technologies.

Preface: Thematic issue on multibody dynamics 2015

Jesús Sánchez Pinedo — Tue, 25 Aug 2020 14:04:44 +0200

Multibody system dynamics is a branch of computational mechanics that deals with modeling principles and computational methods for the dynamic analysis, simulation, and control of complex mechanical systems. These appear in a large spectrum of domains ranging, for example, from standard industrial production of vehicles, rotational machines and mechatronic devices to emerging application fields where biomolecular structures and smart materials are studied at the nanodimensional level. Such versatility of applications is rooted in the basic modeling principles of the discipline, which, being based on the kinematical and dynamical coupling of rigid and flexible bodies with different characteristics and mechanical properties, serve as a powerful tool to study the mechanical and multiphysics behavior of a broad class of systems in engineering and applied sciences.

An immersed boundary hierarchical B-spline method for flexoelectricity

Jesús Sánchez Pinedo — Tue, 25 Aug 2020 10:36:57 +0200

This paper develops a computational framework with unfitted meshes to solve linear piezoelectricity and flexoelectricity electromechanical boundary value problems including strain gradient elasticity at infinitesimal strains. The high-order nature of the coupled PDE system is addressed by a sufficiently smooth hierarchical B-spline approximation on a background Cartesian mesh. The domain of interest is embedded into the background mesh and discretized in an unfitted fashion. The immersed boundary approach allows us to use B-splines on arbitrary domain shapes, regardless of their geometrical complexity, and could be directly extended, for instance, to shape and topology optimization. The domain boundary is represented by NURBS, and exactly integrated by means of the NEFEM mapping. Local adaptivity is achieved by hierarchical refinement of B-spline basis, which are efficiently evaluated and integrated thanks to their piecewise polynomial definition. Nitsche’s formulation is derived to weakly enforce essential boundary conditions, accounting also for the non-local conditions on the non-smooth portions of the domain boundary (i.e. edges in 3D or corners in 2D) arising from Mindlin’s strain gradient elasticity theory. Boundary conditions modeling sensing electrodes are formulated and enforced following the same approach. Optimal error convergence rates are reported using high-order B-spline approximations. The method is verified against available analytical solutions and well-known benchmarks from the literature.

Partitioned analysis of coupled mechanical systems

María Jesús Samper — Wed, 19 Aug 2020 13:13:48 +0200

This is a tutorial article that reviews the use of partitioned analysis procedures for the analysis of coupled dynamical systems. Attention is focused on the computational simulation of systems in which a structure is a major component. Important applications in that class are provided by thermomechanics, fluid–structure interaction and control–structure interaction. In the partitioned solution approach, systems are spatially decomposed into partitions. This decomposition is driven by physical or computational considerations. The solution is separately advanced in time over each partition. Interaction effects are accounted for by transmission and synchronization of coupled state variables. Recent developments in the use of this approach for multilevel decomposition aimed at massively parallel computation are discussed.

Parametrized variational principles for linear electromagnetodynamics

María Jesús Samper — Wed, 19 Aug 2020 12:56:51 +0200

Two families of parametrized mixed variational principles for linear electromagnetody-namics are constructed. The first family is applicable when the current density distribution is known a priori. Its six independent fields are magnetic intensity and flux density, magnetic potential, electric intensity and flux density and electric potential. Through appropriate spe-cialization of parameters the first principle reduces to more conventional principles proposed in the literature. The second family is appropriate when the current density distribution and a conjugate Lagrange multiplier field are adjoined, giving a total of eight independently varied fields. In this case it is shown that a conventional variational principle exists only in the time-independent (static) case. Several static functionais with reduced number of varied fields are presented. The application of one of these principles to construct finite elements with current prediction capabilities is illustrated with a numerical example.

Top-down derivation of doubly asymptotic approximations for structure - fluid interaction analysis

María Jesús Samper — Wed, 19 Aug 2020 12:49:02 +0200

This paper focuses on a class of transient response problems in which a flexible structure is submerged in an acoustic fluid satisfying the three-dimensional wave equation. The structure is discretized by finite element methods while the external fluid is modelled by boundary integral techniques resulting in the appearance of a grid of boundary elements on the 'wet' structural surface.

A Refined Quadrilateral Element for Analysis of Plate Bending

María Jesús Samper — Wed, 19 Aug 2020 11:37:53 +0200

The formulation of a fully compatible general quadrilateral plate bending element is described. The element is assembled from four partially constrained linear curvature compatible triangles, arranged so that no mid-side nodes occur on the external edges of the quadrilateral; thus, the resulting element has only 12 degrees of freedom. Also described is a simple shear distortion mechanism which may be incorporated into the element without changing its basic structure. Results are presented for static analyses with and without shear distortion, and for plate vibration and plate buckling studies, all performed with this quadrilateral element. It is concluded that this is the most efficient general bending element yet devised.

Model Based Partitioned Simulation of Coupled Systems

María Jesús Samper — Wed, 19 Aug 2020 11:25:05 +0200

This tutorial paper is extracted from a set of graduate lectures on the time-domain simulation of structural dynamics and coupled systems. This material has also served as a basis for a CISM lecture series on FSI. For the treatment of coupled systems, emphasis is placed on partitioned analysis procedures. Although the subject emerged in the present form over 20 years ago, the time-consuming study of competing formulations and implementations can be streamlined through the use of various tools such as reduction to model equations, and the help of computer algebra systems.

A Classification of Interface Treatments for FSI

María Jesús Samper — Wed, 19 Aug 2020 11:17:20 +0200

This paper proposes a taxonomy of methods for the treatment of the fluid-structure interface in FSI coupled problems. The top-level classification is based on the presence or absence of Additional Interface Variables (AIV) as well as their type. Associated prototype methods: Direct Force Motion Transfer (DFMT), Mortar and Localized Lagrange Multipliers (LLM) are defined. These are later studied in more detail using a specific FSI benchmark problem used in Ross’ 2006 thesis. Desirable attributes of the interfacing methods are stated and commented upon.

An alphanumeric finite element mesh plotter

María Jesús Samper — Wed, 19 Aug 2020 10:37:48 +0200

A FORTRAN subroutine name MESHPL is described. This routine generates an alphanumeric image of an arbitrary two-dimensional finite element mesh on the line printer. This plotting technique can be used for fast on-line display of nodal points, elements, boundary conditions and loads during the input data preprocessing stage of a finite element analysis.

Solution of linear equations with skyline-stored symmetric matrix

María Jesús Samper — Wed, 19 Aug 2020 10:19:05 +0200

Fortran IV subroutines for the in-core solution of linear algebraic systems with a sparse, symmetric, skyline-stored coefficient matrix are presented. Such systems arise in a variety of applications, notably the numerical discretization of conservative physical systems by finite differences or finite element techniques. The routines can be used for processing constrained systems without need for prearranging equations. The application to ‘superelement’ condensation of large-scale systems is discussed.

Procedures for computer analysis of large nonlinear structural systems

María Jesús Samper — Wed, 19 Aug 2020 10:13:50 +0200

The paper surveys computerized solution techniques for treating large algebraic systems arising in the discrete-element analysis of nonlinear structural systems. Following a brief review of a general-purpose program organization, the principal features of the nonlinear analysis process are discussed. Solution techniques are categorized into four major groups, and the most important algorithms pertaining to each group are described. It is stressed that no particular method can be considered to be uniformly superior to all others if a wide range of practical applications is considered. A problem-adaptive combination of various procedures is therefore recommended for implementation in general-purpose codes.

Optimization of finite element grids by direct energy search

María Jesús Samper — Wed, 19 Aug 2020 10:05:38 +0200

One of the possible approaches to the reduction of computational costs in finite element analysis is the selection of ‘optimal grids’, which produce the ‘best’ answers, in the sense of minimizing a discretization error measure, for a fixed level of computational effort. The grid optimization problem is studied in the case of grids of similar topology having a fixed number of degrees of freedom per node. A general formulation based on weighted-residual error measures is specialized to field problems associated with a positive-definite energy functional, the minimization of which, with respect to variable node locations, is adopted as a grid optimality criterion. The problem is then embedded in the framework of the general nonlinear programming problem, and desirable computational features of candidate search algorithms are described.

Error analysis of penalty function techniques for constraint definition in linear algebraic systems

María Jesús Samper — Wed, 19 Aug 2020 09:55:16 +0200

The penalty function approach has been recently formalized as a general technique for adjoining constraint conditions to algebraic equation systems resulting from variational discretization of boundary value problems by finite difference or finite element techniques. This paper studies the numerical behaviour of the penalty function method for the special case of individual equation constraints imposed on a symmetric system of linear algebraic equations. Constraint representation and computational roundoff error components are distinguished and asymptotically characterized in terms of the penalty function weight coefficients. On the basis of this study, practical rules for the automatic assignment of values to those coefficients within the linear equation solver are proposed. Numerical problems encountered in the case of more general constraints are briefly discussed, and procedures for circumventing such difficulties are suggested.

Stabilization of staggered solution procedures for fluid--structure interaction analysis

María Jesús Samper — Wed, 19 Aug 2020 09:38:19 +0200

This paper addresses direct time integration techniques for the transient response analysis of coupled fluid-structure problems treated by a class of surface interaction approximations. Efficient solution of the resulting equations of motion can be achieved by a modular computer implementation in which separate fluid and structure analyzers are interfaced through extrapolation of the coupling terms. Such an implementation is herein called a staggered solution strategy. The conventional realization of this strategy is handicapped, however, by severe temporal stepsize limitations. Several stabilized formulations are introduced, which circumvent such limitations and achieve unconditional stability for certain extrapolators.

Estática y Resistencia de Materiales

María Jesús Samper — Wed, 19 Aug 2020 09:26:24 +0200

Este libro está dirigido a la formación de estudiantes de ingeniería, arquitectura y
también a ingenieros y arquitectos como base de consulta para el ejercicio de la
profesión. Presenta un enfoque de la Resistencia de Materiales enriquecido con
nuevos conceptos y con ejemplos resueltos mediante herramientas informáticas,
ayudando así a establecer una metodología de trabajo simple, reduciendo los tiempos
de solución de los problemas y permitiendo una mejor asimilación de los conceptos
fundamentales.

El libro es fruto de la extensa experiencia de los autores dedicada a la enseñanza
de esta temática y ha sido pensado para satisfacer la necesidad de conocimiento de
los estudiantes de ingeniería y arquitectura. Con este objetivo se ha escrito este texto
que permite el aprendizaje de las bases para el análisis de estructuras en general y
piezas de máquinas.

Este libro, además de los temas clásicos de la Resistencia de Materiales,
incursiona sobre las bases del tratamiento de piezas de paredes delgadas, de
materiales compuestos laminados y reforzados en general, como así también de
hormigón armado y pretensado, estructuras de sección mixta, etc. Se espera que
todos estos temas sean de ayuda para abordar conceptos más avanzados de cursos
posteriores y desarrollos más profundos en el ejercicio profesional.

Numerical experiments in finite element grid optimization by direct energy search

María Jesús Samper — Wed, 19 Aug 2020 09:18:26 +0200

A series of numerical experiments is conducted to assess the feasibility and practical value of finite element grid optimization based on direct minimization of the total potential energy of the discrete model with respect to the node locations. An implementation relying upon non-linear programming techniques is found to be numerically reliable and to lead to improved grids in accord with engineering intuition. This rigorous approach is hampered, however, by the excessive computational effort required by the energy minimization process. A combination of related techniques is therefore proposed to make dynamic node distribution a useful tool within the framework of large-scale finite element analysis. The combined strategy involves use of substructuring methods, application of a local energy-balancing optimality criterion for fast node distribution, and automatic refinement of previously-improved coarse grids.

Iterative solutions for improving penalty function solutions of algebraic systems

María Jesús Samper — Tue, 18 Aug 2020 14:42:00 +0200

The standard implementation of the penalty function approach for the treatment of general constraint conditions in discrete systems of equations often leads to computational difficulties as the penalty weights are increased to meet constraint satisfaction tolerances. A family of iterative procedures that converges to the constrained solution for fixed weights is presented. For a discrete mechanical system, these procedures can be physically interpreted as an equilibrium iteration resulting from the appearance of corrective force patterns at the nodes of ‘constraint members’ of constant stiffness. Three forms of the iteration algorithm are studied in detail. Convergence conditions are established and the computational error propagation behaviour of the three forms is analysed. The conclusions are verified by numerical experiments on a model problem. Finally, practical guidelines concerning the implementation of the corrective process in large-scale finite element codes are offered.

Computational Aspects of Time Integration Procedures in Structural Dynamics---Part 2: Error Propagation

María Jesús Samper — Tue, 18 Aug 2020 14:16:56 +0200

The propagation of computational error in the direct time integration of the equations of structural dynamics is investigated. Asymptotic error propagation equations corresponding to the computational paths presented in Part 1 are derived and verified by means of numerical experiments. It is shown that there exists an implementation form that achieves optimum error control when used in conjunction with one-derivative methods. No such form is found for two-derivative methods. A numerical beating phenomenon is observed for certain implementations of the average acceleration method and the trapezoidal rule, which from an error propagation standpoint, is highly undesirable.

Computational Aspects of Time Integration Procedures in Structural Dynamics---Part 1: Implementation

María Jesús Samper — Tue, 18 Aug 2020 14:11:47 +0200

A unified approach for the implementation of direct time integration procedures in structural dynamics is presented. Two key performance assessment factors are considered, viz. , computational effort and error propagation. It is shown that these factors are strongly affected by details in the reduction of the second-order equations of motion to a system of first-order equations, and by the computational path followed at each time step. This paper is primarily devoted to the study of the organization of the computational process. Specific implementation forms derivable from the unified approach are studied in detail, and rated accordingly.

Direct integration methods in nonlinear structural dynamics

María Jesús Samper — Tue, 18 Aug 2020 14:03:09 +0200

This paper reviews some recent developments in direct time integration methods for nonlinear structural dynamics. The developments pertain to the use of linear multistep difference operators in conjunction with the pseudo-force approach. The paper is organized into three main sections. An introductory section provides an overview of the transient response analysis problem. A section on computational aspects deals with the organization of the numerical calculations; this material is largely based on a recent detailed study of linear dynamic calculations [1–2]. A section on integration methods highlights algorithmic aspects that impact the selection of integrator for nonlinear problems and discusses adaptive analysis features such as stepsize control and implicit matrix scaling techniques. An appendix section outlines the functional organization of modular “integration driving” software.

A contour-line printplotter for finite element work

María Jesús Samper — Tue, 18 Aug 2020 13:58:57 +0200

A Fortran subroutine for producing countour line printplots of functions defined at the nodes of an arbitrary two-dimensional finite element mesh is presented. This display technique is useful for quick inspection of analysis results and as guide for downstream use of more sophisticated graphics equipment.

Symposium on future trends in computerized structural analysis and synthesis

María Jesús Samper — Tue, 18 Aug 2020 13:53:58 +0200

Database Management in Scientific Computing Part I: General Description

María Jesús Samper — Tue, 18 Aug 2020 13:26:24 +0200

Techniques for generalized data management are gradually making inroads in scientific computing in general and computerized engineering analysis in particular. This development parallels in many ways the rapid acceptance of the centralized database concept in business-oriented processing during the 1970s. Scientific database manipulation systems face, however, a specialized general features of scientific data management from a functional standpoint. Special emphasis is given to the discussion of trends in the development of large-scale programs, as well as the assembly of database-linked program networks for engineering analysis.

Axisymmetric free vibration of a submerged spherical shell

María Jesús Samper — Tue, 18 Aug 2020 13:18:34 +0200

Previous studies have produced only partial solutions for this classical configuration. It is shown here how complete solutions are readily obtained from simple polynomial expressions. Numerical results in graphical form are given for a steel shell submerged in water as functions of a parameter related to the shell's thickness-to-radius ratio. It is found that descriptions based upon added-mass and added-damping perturbations of the shell's in vacuo free-vibration characteristics can be misleading.

Database management in scientific computing—II. Data structures and program architecture

María Jesús Samper — Tue, 18 Aug 2020 13:13:20 +0200

The second of a three-part paper on scientific database management prepares the ground for the operational description of a multilevel data management system in Part III. Following a detailed categorization of data and storage structures, principles of program architecture deemed necessary to make most efficient use of centralized data management techniques are discussed. General operational requirements of data management systems are presented, and the notion of activity levels introduced. This part closes with a brief review of the evolution of data management techniques in the context of computerized structural analysis.

Staggered transient analysis procedures for coupled mechanical systems: Formulation

María Jesús Samper — Tue, 18 Aug 2020 12:54:39 +0200

Coupled-field dynamic problems in mechanics have been traditionally solved by treating the entire system as one computational entity. More recently, increasing attention has been directed to an alternative approach; partition the governing equations into subsystems, which are treated by subsystem analyzers. The selection of the subsystems may be based on weak-coupling considerations, widely different time response characteristics, isolation of nonlinear effects, or more pragmatic reasons such as the availability of analyzer software. In a staggered solution procedure the solution state of the coupled system is advanced by sequentially executing the subsystem analyzers. Subsystem coupling terms are accounted for by temporal extrapolation techniques.This paper focuses on the formulation and computer implementation of staggered solution procedures for two-field problems governed by semidiscrete second-order coupled differential equations. Such equations find application in the modeling of structure-fluid, structure-soil and structure-structure interaction. Following an introductory description of candidate problems and general solution strategies, direct time integration methods are formulated and applied to the coupled system. Staggered solution procedures are constructed through two alternative approaches which are based upon partitioning at the difference and differential equation level, respectively. Characteristic equations that govern the stability of the resulting implementations are derived, and the selection of stable extrapolators discussed. Finally, possible extensions of staggered solution procedures to coupled-field static and eigenvalue problems are suggested.

A Family of Early-Time Approximations for Fluid-Structure Interaction

María Jesús Samper — Tue, 18 Aug 2020 12:18:59 +0200

A hierarchical family of early-time, high-frequency asymptotic, surface interaction approximations is derived for a structure submerged in an infinite acoustic fluid. Kirchhoff's retarded-potential integro-differential formulation is used as exact source formula. The well-known plane-wave and curved-wave approximations result as the first two members of the hierarchy. Acoustic impedance characteristics of the first four members are exhibited for several sample geometries.

Partitioned Transient Analysis Procedures for Coupled-Field Problems: Accuracy Analysis

María Jesús Samper — Tue, 18 Aug 2020 11:44:09 +0200

Partitioned solution procedures for direct time integration of second-order coupled-field systems are studied from the standpoint of accuracy. These procedures are derived by three formulation steps: implicit integration of coupled governing equations, partitioning of resulting algebraic systems and extrapolation on the right-hand partition. It is shown that the combined effect of partition, extrapolation, and computational paths governs the choice of stable extrapolators and preservation of rigid-body motions. Stable extrapolators for various computational paths are derived and implementation-extrapolator combinations which preserve constant-velocity and constant-acceleration rigid-body motions are identified. A spectral analysis shows that the primary error source introduced by a stable partition is frequency distortion. Finally, as a guide to practical applications, the advantages and shortcomings of five specific partitions are discussed.

Nonlinear Static Analysis of Deep Ocean Mining Pipe—Part I: Modeling and Formulation

María Jesús Samper — Tue, 18 Aug 2020 11:33:28 +0200

A static analysis procedure is formulated and implemented for the numerical determination of nonlinear static equilibrium configurations of deep ocean risers or mining pipes. This implementation involves selection of a finite element model, modeling of structure, surface and subsurface environment and external forces, and solution of nonlinear equilibrium equations. The riser is modeled by three-dimensional beam finite elements which include axial, bending, and torsional deformations. These deformations are coupled through geometrically nonlinear effects. The resulting tangent-stiffness matrix includes three contributions identified as linear, geometric (initial-stress) and initial-displacement stiffness matrices. For the solution, a combination of load-parameter incrementation, state updating of fluid properties, and corrective Newton-Raphson iteration is used. The resulting riser configuration reflects the realistic modeling of environments and external forces. The static equilibrium solution can be used as initial condition for vibration or transient analysis. Numerical studies are presented in Part II of this paper.

Nonlinear Static Analysis of Deep Ocean Mining Pipe—Part II: Numerical Studies

María Jesús Samper — Tue, 18 Aug 2020 11:29:30 +0200

This part applies the modeling and solution techniques discussed in Part I to the computerized steady-state deflection analysis of deep ocean mining pipe systems. For accurate analysis, a realistic representation of drag forces along the pipe is required. This is affected by three major factors. First, in a temperature-stratified ocean, the viscosity and consequently the Reynolds number (Re) and drag coefficient vary significantly along the depth. Second, three-dimensional subsea current velocity distribution must be combined with ship velocity data and pipe configuration in the calculation of relative pipe-fluid velolcities. Finally, the drag coefficient versus Re, which varies between experiments and becomes very sensitive in the transition region, has to be properly characterized. Several cases that illustrate these parametric effects are presented for an 18,000-ft pipe modeled by three-dimensional beam elements which include coupled axial, bending and torsional deformations. The sensitivity of the results to environment characterization suggests that, for deep-ocean applications, a review of many current modeling and analysis practices is necessary.

Trends in computational engineering

María Jesús Samper — Tue, 18 Aug 2020 11:23:45 +0200

This article presents the author's views on computational engineering. This is an emerging branch of the applied sciences shaped by the interaction of engineering, mathematics, and computer sciences, and paced by present advances in software technology and computer hardware. Impact of these advances on various aspects of engineering software are discussed, and predictions as to future effects are ventured. An annotated multidisciplinary reference list is provided for curious readers.

Architecture of a distributed analysis network for computational mechanics

María Jesús Samper — Tue, 18 Aug 2020 11:16:05 +0200

An integrated software system called NICE (Network of Interactive Computational Elements) is presently under development at the Applied Mechanics Laboratory. The overall purpose of this development is to further the formulation, implementation and application of advanced computational methods in fluid and solid mechanics. From a software engineering standpoint, system design stresses functional modularity, decentralization, adaptability to interactive computing environments, and ability to accommodate research, development, analysis and testing activities. A clear separation is established between architectural elements such as analysis control and data management, and result-productive computational components called processors. This paper gives a functional overview of the NICE architecture, for which the author is responsible. Control functions that shape the user's perception of the system are emphasized.

Interfacing Finite Element and Boundary Element Discretizations

María Jesús Samper — Tue, 18 Aug 2020 11:10:54 +0200

A review is provided of various methods for coupling a mechanical finite element model to an infinite external acoustic domain. The associated physical problem involves a three-dimensional structure, submerged in an acoustic fluid, and a pressure shock impinging on the structure. Of primary concern is the structural response and, in particular, the structure's survivability. The governing matrix equation of motion for the dynamic response of a discrete structure is considered along with the fluid equations of the interaction equations. Three approaches for solving the obtained coupled finite element/boundary element system are reported, giving attention to the 'field elimination' method, the procedure of simultaneous integration, and a partitioned integration process.

Software for testing stability polynomials

María Jesús Samper — Tue, 18 Aug 2020 11:06:59 +0200

Fortran 77 routines for testing root-locus stability conditions on real polynomials with the Routh and Schur-Cohn algorithms are presented. The use of the routines is illustrated by two case studies.

Partitioned Analysis of Coupled Systems

María Jesús Samper — Tue, 18 Aug 2020 10:41:17 +0200

This paper reviews partitioned analysis procedures for the analysis of coupled-field dynamical problems. These problems involve two or more distinctive subsystems that are tightly coupled. Examples are provided by fluid-structure, soil-structure, thermal-structure and structure-magnetodynamic interactions. The computer analysis of such systems depends on the integration of analysis capabilities for the separate components. Partitioned analysis procedures provide an efficient and modular way of achieving that integration. These procedures advance the solution of the coupled problem in a staged fashion.

Doubly asymptotic approximations for vibration analysis of submerged structures

María Jesús Samper — Tue, 18 Aug 2020 10:29:09 +0200

Doubly Asymptotic Approximations (DAAs) are differential equations for boundary-element analysis of the interaction between a complex structure and a surrounding infinite medium. In this paper, the use of first- and second-order DAAs for steady-state vibration analysis of submerged structures is examined. First, the governing discrete-element equations for the general problem are set down and discussed. Then the accuracy of three DAA forms is studied through the generation of numerical results for a submerged spherical shell. Although the first-order DAA is found to be inadequate, the two second-order forms show considerable promise.

Professional workstations

María Jesús Samper — Tue, 18 Aug 2020 10:18:13 +0200

Professional workstations are dedicated computers that possess sufficient hardware power and software capabilities to allow the routine performance of job-related activities by professional users. The advent of these computers reflects current trends in decentralization and specialization of computer equipment. The paper presents an informal review of classes of workstations of potential interest to engineers and scientists. The review was motivated by projected computing needs in a software- intensive research-and-development industrial laboratory.

A triangular element with rotational degrees of freedom

María Jesús Samper — Tue, 18 Aug 2020 09:46:04 +0200

A new plane-stress triangular element is derived using the free formulation of Bergan and Nygård. The triangle possesses nine degrees of freedom: six corner translations and three corner normal rotations. The element is coordinate-invariant and passes the patch test for any geometry. Two free parameters in the formulation may be adjusted to optimize the behavior for in-plane bending patterns. With the recommended parameter choices the element performance is significantly better than that of the constant-strain triangle. Because of the presence of the rotational freedoms, this new element appears especially suitable as membrane component of a flat triangular element for modelling general shell structures.

Finite element analysis of shock-induced hull cavitation

María Jesús Samper — Tue, 18 Aug 2020 09:36:08 +0200

This paper describes the theoretical formulation and computational implementation of a method for treating hull cavitation in underwater‐shock problems. In addition, the method can be applied to the analysis of submerged structures that contain internal fluid volumes. In the present implementation, the doubly asymptotic approximation (DAA) serves to simulate a radiation boundary that is located away from the fluid‐structure surface at a distance sufficient to contain any cavitating region. The enclosed fluid is discretized with volume finite elements that are based upon a displacement‐potential formulation. An explicit time‐integration algorithm is used to advance the solution in the fluid‐volume region, implicit algorithms are used for the structure and DAA boundary, and a staggered solution procedure has been developed to treat the interface condition. Results for two example problems obtained with the present implementation show close agreement with those obtained by other methods.

A command reader for interactive programming

María Jesús Samper — Mon, 17 Aug 2020 14:48:04 +0200

A simplified command line reader suitable for building interactive programs based on Fortran 77 is presented. The reader is a 20:1 condensation of the comprehensive command language interpreter CLIP that supports the NICE integrated software system. The present reader, called TinyCLIP. has been prepared to illustrate basic elements of command-driven programming for beginners interested in writing Fortran-based interactive applications software. The reader is table driven. Data lines given to the reader are parsed into items which are stored in a table. The table can be subsequently accessed by the program that processes the commands. Tools for extending the basic language are briefly discussed and specific extensions suggested.

Penalty‐function iterative procedures for mixed finite element formulations

María Jesús Samper — Mon, 17 Aug 2020 14:42:46 +0200

Iterative methods for solving mixed finite element equations that correct displacement and stress unknowns in ‘staggered’ fashion are attracting increased attention. This paper looks at the problem from the standpoint of allowing fairly arbitrary approximations to be made on both the stiffness and compliance matrices used in solving for the corrections. The resulting iterative processes usually diverge unless stabilized with Courant penalty terms. An iterative procedure previously constructed for equality-constrained displacement models is recast to fit the mixed finite element formulation in which displacements play the role of Lagrange multipliers. The penalty function iteration is shown to reduce to an ordinary staggered stress-displacement iteration if the weight is set to zero. Convergence conditions for these procedures are stated and the potentially troublesome effect of prestress modes noted.

Symmetrization of the contained compressible‐fluid vibration eigenproblem

María Jesús Samper — Mon, 17 Aug 2020 14:37:26 +0200

This paper studies the symmetrization of the problem of coupled vibrations of an acoustic fluid enclosed in an elastic container. The container structure is discretized by a displacement finite element formulation and the acoustic fluid by a displacement‐potential formulation. The vibrations of this physically conservative coupled system are governed by an unsymmetric algebraic eigenvalue problem. Eight equivalent symmetric forms of this problem are exhibited. The fluid‐pressure formulation leads to a similar unsymmetric eigenproblem, which in turn can be converted to another eight equivalent symmetric forms.

Traversing Critical Points with Penalty Springs

María Jesús Samper — Mon, 17 Aug 2020 14:30:13 +0200

We present aspects of computer implementation of finite element structural analysis capabilities into a series of concurrent machines. We approach the implementation issues from the viewpoint that the design of data structures for finite element computations will play a crucial role in the constructs of computational modules, data transfer mechanisms among processes, and, consequently, desirable non-numerical and numerical algorithms. We account for the essential architectural features of local memory machines, shared memory machines and connection machines that are pertinent to finite element computations. We outline a concurrent FEM system that we advocate, and report our activities on system design and algorithm development. We report also on our 'hands-on' experience in concurrent finite element computations using some of the existing multiprocessors such as Intel's hypercube iPSC, Encore's Multimax, Alliant/FX8, and the CRAY as a benchmark case.

A triangular element based on an energy-orthogonal free formulation

María Jesús Samper — Mon, 17 Aug 2020 14:07:37 +0200

A new Kirchhoff triangular plate-bending element with nine degrees of freedom is derived. The assumed shape functions are nonconforming and consist of a complete quadratic expansion complemented by three cubic modes that are energy-orthogonal to the quadratic expansion. The derivation is based on the free formulation of Bergan and Nygård, which satisfies the conditions of invariance and the patch test. An explicit expression is obtained for the inverse transformation matrix required in this formulation, which makes the stiffness computations extremely efficient. The aspect ratio sensitivity of the element under cylindrical bending modes can be lessened by scaling the higher-order stiffness through coefficients determined by a superlinear patch test technique. Numerical experiments indicate that the new element outperforms previously derived 9-dof triangular elements based on displacement modes.

Will the Force Method Come Back?

María Jesús Samper — Mon, 17 Aug 2020 14:01:59 +0200

The force method of structural analysis was overtaken by the displacement method in the mid Sixties, and has disappeared from the scene for few specialized applications. Virtually all existing general-purpose finite element programs are based on the direct stifness method (DSM) introduced three decades ago by Turner et al. (1956) and Turner (1959). The DSM combines the displacement method of solution with the direct, element-by-element assembly of the stifness equations. The simplicity and efficiency of the DSM for general applications have not been matched to date; it has the polished "black box" feeling of Lagrange's analytical mechanics.

Penalty Spring Stabilization of Singular Jacobians

María Jesús Samper — Mon, 17 Aug 2020 13:49:27 +0200

A limit-point treatment is presented which is a synthesis of two earlier techniques. To traverse limit points, Sharifi and Popov (1970) introduced fictitious stiffnesses in the form of rank-one updates but did not use auxiliary systems. Rheinboldt (1981) discussed the use of auxiliary systems in conjunction with the partition of the Jacobian matrix. The procedure presented in this paper avoids the need for partitioning and consequent special treatment of the elements in the ith row and column of K; only the diagonal entry is changed. It enjoys the added advantage that none of the auxiliary system right-hand sides requires access to elements of the K matrix.

Symmetrization of coupled eigenproblems by eigenvector augmentation

María Jesús Samper — Mon, 17 Aug 2020 13:01:22 +0200

The problem of elastoacoustic vibrations of a fluid enclosed in a flexible container leads to a generalized unsymmetric eigensystem of special form. This system can be symmetrized in eight different ways by eigenvector augmentation followed by static condensation.

Partitioned analysis of coupled mechanical systems

María Jesús Samper — Mon, 17 Aug 2020 12:54:30 +0200

Partitioned analysis is a method by which sets of time-dependent ordinary differential equations for coupled systems may be numerically integrated in tandem, thereby avoiding brute-force simultaneous solution. The coupled systems addressed pertain to fluid—structure, fluid—soil, soil—structure, or even structure—structure interaction. The paper describes the partitioning process for certain discrete-element equations of motion, as well as the associated computer implementation. It then delineates the procedure for designing a partitioned analysis method in a given application. Finally, examples are presented to illustrate the concepts. It is seen that a key element in the implementation of partitioned analysis is the use of integrated, as opposed to monolithic software.

Treatment of coupled fluid-structure interaction problems by a mixed variational principle

María Jesús Samper — Mon, 17 Aug 2020 11:33:50 +0200

A general three-field variational principle is obtained for the motion of an acoustic fluid enclosed in a rigid or flexible container by the method of canonical decomposition applied to a modified form of the wave equation in the displacement potential. The general principle is specialized to a mixed two-field principle that contains the fluid displacement potential and pressure as independent fields. Semidiscrete finite-element equations of motion based on this principle are displayed.

Parametrized multifield variational principle in elasticity. I: Mixed functionals

María Jesús Samper — Mon, 17 Aug 2020 11:21:42 +0200

A one-parameter family of mixed variational principles for linear elasticity is constructed. This family includes the generalized Hellinger-Reissner and total potential energy principles as special cases. The presence of the free parameter offers an opportunity for the systematic derivation of energy-balanced finite elements that combine displacement and stress assumptions. It is shown that Fraeijs de Veubeke's stress-assumption limitation principle takes a particulary elegant expression in terms of the parametrized discrete form. Other possible parametrizations are briefly discussed.