Domain decomposition methods for parallel solution of shape sensitivity analysis problems

Summarization: This paper presents the implementation of advanced domain decomposition techniques for parallel solution of large-scale shape sensitivity analysis problems. The methods presented in this study are based on the FETI method proposed by Farhat and Roux which is a dual domain decomposition implementation. Two variants of the basic FETI method have been implemented in this study: (i) FETI-1 where the rigid-body modes of the floating subdomains are computed explicitly. (ii) FETI-2 where the local problem at each subdomain is solved by the PCG method and the rigid-body modes are computed explicitly. A two-level iterative method is proposed particularly tailored to solve re-analysis type of problems, where the dual domain decomposition method is incorporated in the preconditioning step of a subdomain global PCG implementation. The superiority of this two-level iterative solver is demonstrated with a number of numerical tests in serial as well as in parallel computing environments.Presented on: International Journal for Numerical Methods in Engineerin

Intelligent computational paradigms in earthquake engineering

The enormous advances in computational hardware and software resources over the last fifteen years resulted in the development of non-conventional data processing and simulation methods. Among these methods artificial intelligence (AI) has been mentioned as one of the most eminent approaches to the so-called intelligent methods of information processing that present a great potential for engineering applications. Intelligent Computational Paradigms in Earthquake Engineering contains contributions that cover a wide spectrum of very important real-world engineering problems, and explore the implementation of neural networks for the representation of structural responses in earthquake engineering. This book assesses the efficiency of seismic design procedures and describes the latest findings in intelligent optimal control systems and their applications in structural engineering. Intelligent Computational Paradigms in Earthquake Engineering presents the application of learning machines, artificial neural networks and support vector machines as highly-efficient pattern recognition tools for structural damage detection. It includes an AI-based evaluation of bridge structures using life-cycle cost principles that considers seismic risk, and emphasizes the use of AI methodologies in a geotechnical earthquake engineering application. © 2007 by Idea Group Inc. All rights reserved

Effects of soil non-linearity on the seismik distressof retaininig walls

Summarization: Despite the structural simplicity of retaining walls, their seismic response is a rather complicated problem. What makes that response so complicated is the dynamic interaction between the wall and the retained soil, especially when material and/or geometry non-linearities are present. This paper aims to examine how and to what extent the potential soil non-linearity may affect both the dynamic behavior of a rigid non-sliding retaining wall and also the seismic response of the retained soil layer. For this purpose an extensive parametric study, based on two-dimensional dynamic finite-element analyses, is conducted. Soil non-linearity is realistically taken into account via a computationally efficient equivalent-linear procedure. The examined numerical model is studied under different excitations and various levels of the imposed ground motion maximum accelerations to examine more thoroughly the influence of material non-linearity. The results of this study justify the hypothesis that the non-linear soil behavior has a considerable impact not only on the dynamic earth pressures developed on the wall, but on the amplification of the acceleration levels on the backfill soil as well. Therefore, it becomes evident that seismic codes and geotechnical design practice should take this impact into serious consideration.Παρουσιάστηκε στο: The 14 th World Conference on Earthquake Engineerin