Abstract

The aim of this paper is to partially solve the problem of visualization of clusters of particles resulting from numerical methods in engineering. Two methods for removing non-visible particles from some view point of the camera were developed. These are divided depending on the type of information available: particle systems with contour information (surface mesh) and particle systems without contour information (methods without mesh). In both cases, the results are very good, it is achieved removing large amount of particles that do not affect the final image, permitting interact with the results of numerical methods.

Abstract

The present study compares three different solutions for the direct problem of Electrical Impedance Tomography using the finite difference method. In this technique, electrodes are positioned on the boundary of a volume to be studied, and in two of them current patterns are injected and measurements of electrical potential are made in the remaining electrodes. The numerical inversion of the data allows reconstruction of the analyzed domain. Two new approximations are proposed for the direct problem and comparisons are performed based on results available in the literature. In the study performed here, in one of the proposed approximations it was observed a significant improvement in accuracy compared to results obtained with the approximations in the literature.

Abstract

This degree thesis deals with the estimation of towing tank resistance of fishing vessel with round bilge. First, a state of art of fishing vessel is presented. Second, the usual statistical methods to predict the towing tank resistance of fishing vessel are analyzed. Third, a typical fishing vessel with round bilge is designed. Some parameters of designed fishing vessel are analysed. Fourth, the statistical method are applied to fishing vessel. The results are compared. Fifth, a towing tank analysis with CFD code Tdyn is carried out. The results of CFD and other numerical mentod are compared. Finally some conclusions are presented.

Abstract

The behavior of structures subjected to earthquakes demonstrates that the phenomena of soil-structure and fluid-structure interaction have a great influence on the structural response, especially in the case of structures such as dams, tanks, elevated water tanks, marine platforms, intake towers, etc. The numerical study of these phenomena requires solving problems in which the coupling between two solids or between a solid and a fluid occurs only at the surfaces of contact between them. This chapter describes several numerical procedures used to solve the problem of seismic interaction. For this, it is necessary to have a record of seismic motion on the interface that separates the area of ​​the soil considered in the analysis, which defines a theoretical surface sometimes called base rock. Below this, the soil can be assumed infinitely stiff or with a certain flexibility. To obtain an accelerogram at the level of the base rock, a deconvolution of the seismic motion available on the ground surface must be made. Then, this calculated accelerogram is applied on the soil-structure-fluid system.

Abstract

The paper presents an overview on the computational tools developed in CIMNE for the analysis of the behavior of rockfill dams in overtopping scenarios, as well as for the design of protections systems against overtopping. In this latter case two different applications are presented: the design tool for a wedge shaped blocks (WSB) shoulder protection and the computational models for the analysis of the hydraulic performance of highly convergent spillways. Advanced finite element techniques are combined with particle techniques and artificial neural networks in the framework of the Kratos Multiphysics for reaching the optimal solution procedure for any of the above mentioned problems. An extensive validation is carried out using experimental data provided by the SERPA group of the Technical University of Madrid.

Abstract

A general constitutive model adequate for analysis of the thermomechanical response of composite materials is presented. The model is based on the mixture of the basic substances of the composite and allows the evaluation of the interdependence between the constitutive behaviour of different compounding materials. The behaviour of the each compound is modelled by a general anisotropic thermo‐elasto‐plastic model, termed the ‘base model’. The different base models for each compound are combined using mixing theory to simulate the behaviour of the multiphase material.

Abstract

The need for remeshing when computing flow problems in domains suffering large deformations has motivated the implementation of a tool that allows the proper transmission of information between finite element meshes. Because the Lagrangian projection of results from one mesh to another is a dissipative method, a new conservative interpolation method has been developed. A series of constraints, such as the conservation of mass or energy, are applied to the interpolated arrays through Lagrange multipliers in an error minimization problem, so that the resulting array satisfies these physical properties while staying as close as possible to the original interpolated values in the L2 norm. Unlike other conservative interpolation methods that require a considerable effort in mesh generation and modification, the proposed formulation is mesh independent and is only based on the physical properties of the field being interpolated. Moreover, the performed corrections are neither coupled with the main calculation nor with the interpolation itself, for which reason the computational cost is very low.

Abstract

This work is a brief report about the problem of life -or, durability study- of structural materials, undergoing mechanical, thermal and chemical actions. This document is approached from numerical techniques and, it highlights the potential of these types of tools un the study of structures undergoing very complex and coupled phenomena.

Abstract

STEM education is a strategy based on four disciplines (science, technology, engineering and mathematics), integrated in an innovative interdisciplinary approach. Although, the concept of STEM education is more relevant today, the discussion of a teaching model with special attention in the four subjects aforementioned began in the early 2000s. Taking into account this context, the strategy presented in this paper has been disseminated in Bolivia's main universities for the last five years. A country that has not yet managed to associate basic disciplines such as calculus, matrix algebra, and/or differential equations to solve problems of an applicative nature, that is, to establish the link between theory and practice. To establish the connection, it is necessary to deduce differential equations associated with practical problems; solve these equations with numerical methods, appeal to the simulation concept to later introduce programming languages like ''Python/VPython'' to build virtual laboratories. The classical problem addressed for this purpose is the satellite of two degrees of freedom.

Abstract

Numerical methods are largely used to solve problems and complex natural physical phenomena that do not have an analytical solution. Its approach to approximation enables the resolution of technical and scientific problems with great fidelity of results. The Smoothed Particle Hydrodynamics (SPH) method is a method whose origin derives from the study of astrophysical problems and which was applied to the study of fluid behavior. Therefore, it is currently a powerful tool capable of solving major problems related to fluid dynamics, used by the academy and in commercial functions. The method is Lagrangean and does not depend on a numerical mesh, which is responsible for reading information at every moment of time, but rather that small particles, discretized in the domain, have their own information and carry it for as long as necessary. The method was applied in an industrial refrigeration tank as a form of modeling to avoid application costs and improvements of operation by the simulator DualSphysics. Two simulations were made with different geometries, being original and modified. The proposed new mixer model achieved small gains in energy savings, better fluid flow and distribution, and greater energy utilization of the system. The method proved to have high computational demand, however, high ability to work with fluids and deformations common to these problems.