S.R. Santos¹, L.C. Matioli², A.T. Beck³

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.1, pp. 23-56, 2012, DOI:10.3970/cmes.2012.083.023

Abstract Solution of structural reliability problems by the First Order method require optimization algorithms to find the smallest distance between a limit state function and the origin of standard Gaussian space. The Hassofer-Lind-Rackwitz-Fiessler (HLRF) algorithm, developed specifically for this purpose, has been shown to be efficient but not robust, as it fails to converge for a significant number of problems. On the other hand, recent developments in general (augmented Lagrangian) optimization techniques have not been tested in aplication to structural reliability problems. In the present article, three new optimization algorithms for structural reliability analysis are presented. One algorithm is based on… More >

Guangming Yao¹, Siraj-ul-Islam², Božidar Šarler²

CMES-Computer Modeling in Engineering & Sciences, Vol.59, No.2, pp. 127-154, 2010, DOI:10.3970/cmes.2010.059.127

Abstract This paper focuses on the comparative study of global and local meshless methods based on collocation with radial basis functions for solving two dimensional initial boundary value diffusion-reaction problem with Dirichlet and Neumann boundary conditions. A similar study was performed for the boundary value problem with Laplace equation by Lee, Liu, and Fan (2003). In both global and local methods discussed, the time discretization is performed in explicit and implicit way and the multiquadric radial basis functions (RBFs) are used to interpolate diffusion-reaction variable and its spatial derivatives. Five and nine nodded sub-domains are used in the local support of… More >

L. Dieng¹, A. Abdul-Latif², M. Haboussi, C. Cunat³

CMC-Computers, Materials & Continua, Vol.6, No.1, pp. 21-34, 2007, DOI:10.3970/cmc.2007.006.021

Abstract Being of particular interest in this work, a complicated phenomenon related to cyclic softening of metallic polycrystals is modeled. As in the Waspaloy, this phenomenon can take place when a non-proportional tension-torsion cyclic loading of 90° out-of-phase is followed, after cyclic steady state, by a uniaxial one (tension-compression) with the same maximum equivalent plastic strain. By using the DNLR (Distribution of Non Linear Relaxation) model recently proposed by the authors describing the cyclic plasticity of metals, a new extension is here developed. It is recognized that such an extension can satisfactorily reproduce this softening phenomenon. It is noteworthy that this… More >