Documents published in Scipedia

• A 4-node thin shell element based on co-rotational for laminated composite structures

  S. Qiao, H. Gao, L. Hua, F. Wang

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

  
  

  Abstract

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

  Abstract
  The finite formulation of the 4-node thin shell element based on Co-rotational (CR) and Timoshenko`s theory was presented for the analysis of laminated composite structures. [...]

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• Comparison of algorithms for reliability-based structural optimization

  H. Cortés, C. Camacho Lopez, R. Calvo OCampo

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

  
  

  Abstract

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

  Abstract
  The design of reliable structures requires robust tools that allow the analysis of the behavior of the system subject to variability in its resistance and applied loads. For [...]

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• Research on rational layout of strut arms of tainter gate in vertical frame

  X. Zhang, Z. Wang, D. Sun

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

  
  

  Abstract

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

  Abstract
  The overall stability of hydraulic tainter steel gate decrease seriously, and they are caused by improper structure layout of the two-way eccentric compression of struts. [...]

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• Fuzzy inference system for muti-hazard physical risk assessment in urban areas

  M. Carreño, N. Lantada, N. Jaramillo

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

  
  

  Abstract

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

  Abstract
  The urban areas may be exposed to different natural hazards; in order to jointly evaluate the potential risk, this article proposes a methodology for the qualitative assessment [...]

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• The geological history analysis of the friction angle in transported soils and their importance in the bearing capacity of shallow foundations

  C. Mendoza, J. Ruge, B. Caicedo

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

  
  

  Abstract

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

  Abstract
  This work shows the variability of the friction angle based on the geological history, over the bearing capacity of shallow foundations. This study was developed through the [...]

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• Application of lattice Boltzmann method for surface runoff in watershed

  V. Galina, J. Cargnelutti, E. Kaviski, L. Gramani, A. Lobeiro

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

  
  

  Abstract

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

  Abstract
  Derived from simplifications of the Saint-Venant equations, the kinematic wave model has the ability to describe the behavior of surface runoff in watersheds. This paper aims [...]

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• Nonlinear analysis of beams, plane frames and arch using a dierent co-rotating beam element

  W. Matias Silva, S. Silva, M. Gutiérrez

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

  
  

  Abstract

  The present work uses a co-rotating approach for obtain the internal forces and tangent stiness matrices for three plane beam elements. All of them are based on the same co-rotational approach, and di er by the strain de nition used in the local co-rotational coordinate system. Based on the Bernoulli assumption, the rst two elements use a linear and a shallow arch strain de nition, respectively. The third element is based on the Timoshenko assumption with linear interpolations for the displacements. Some examples are presented and the numerical results demonstrate that the beam elements here presented are able to perform the nonlinear analysis of plane frames and 2D arches and to handle large rotations too.

  Abstract
  The present work uses a co-rotating approach for obtain the internal forces and tangent stiness matrices for three plane beam elements. All of them are based on the same co-rotational [...]

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• Application of the Verlet method for the simulation of a gravitational system of n bodies

  J. Medina, C. Acosta, M. Flota-Bañuelos, R. Peón-Escalante

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

  
  

  Abstract

  In this paper we propose a numerical solution (software simulation) of the "problem of n bodies" that interact gravitationally based on the formulation of Verlet. Additionally a program is designed that graphically shows the results of this numerical solution, which details the different trajectories, for different conditions of mass, speed and distance between the n objects that interact. The interaction of the user with the graphical interface, is performed particle by particle. 

  Abstract
  In this paper we propose a numerical solution (software simulation) of the "problem of n bodies" that interact gravitationally based on the formulation of Verlet. [...]

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• Control law for a robot network formation using static diffusive coupling

  S. Durazo-Acevedo, A. Aguilar-Bustos, E. Bugarin

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

  
  

  Abstract

  This article describes a control proposal for a formation objective of a robot network in collaborative work with static diffusive coupling using tools derived from graph theory. This proposal is guaranteed by the stability theory of Lyapunov and it is validated with results in simulation and experimentation. As an important part of this work, it is detailed like a tutorial the procedure for the formulation of the robot network addressed and also it is proposed a formation control law with procedure for non-collision between the robots that form the network using the same network topology.

  Abstract
  This article describes a control proposal for a formation objective of a robot network in collaborative work with static diffusive coupling using tools derived from graph [...]

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• A memetic algorithm based on Artificial Bee Colony for optimal synthesis of mechanisms

  E. Vega-Alvarado, E. Portilla-Flores, G. Munoz-Hernandez, E. Mezura-Montes, G. Sepúlveda-Cervantes, P. Bautista-Camino

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

  
  

  Abstract

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

  Abstract
  In this paper a novel proposal of a modular hybrid algorithm as a tool for solving real-world engineering problems is presented. A memetic algorithm, MemMABC, is implemented [...]

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