Interactive-Computer Aided Reliability Engineering

Abstract

The Interactive-Computer Aided Reliability Engineering (I-CARE) system, supporting reliabilitybased design and optimization of large structural systems is presented. Sizing, shape, configuration, and topology optimization design problems may be considered. Integration of different optimization algorithms with first-order reliability methods and with the continuum method of design sensitivity analysis resulted in an efficient and highly flexible computational environment. A general interactive design methodology is proposed and its use is demonstrated on the design of a guillotine shear machine tool. oduction Structural analysis and optimization procedures have undergone considerable refinement during the last years due to advances in computer technology. This also resulted in the possibility of rationally accounting for the uncertain properties of strength, loading, and geometry as well as of mathematical models. Reliability-based optimization (RBO) became an important tool for design of advanced structural systems. However, application of RBO to large systems, characterized by a large number of stochastic variables and failure functions, still experiences severe problems, mostly related to a relatively low computational efficiency and slow convergence of the optimization process. Performing RBO in a fully automated way quite often leads to a useless design due to errors in the problem definition, or to a poor local minimum after expensive computation. Instcad of automating thc RBO process, an interactive approach would be more useful4. Moreover, the interactive approach may be extended to the whole design process. An interactive design environment must provide a systematic design approach which is applicable to general design problems; utilize commercially available codes to define geometric as well as finite clement models, analyze, and optimize the structure; support parametrization of the structural geometry, material, and loading by introducing deterministic and stochastic parameters; allow for the definition of local and global performances; allow for the definition of reliability and optimization models; combine visual capabilities with interactive analysis and optimization methods to efficiently improve designs; combine fast and accurate analysis and optimization methods with approximate methods to maximize computational efficiency. This paper presents such an integrated environment called Interactive-Computer Aided Reliability Engineering (I-CARE). It allows to perform reliability-based size, shape, configuration, and topology design and optimization of large structural systems. ICARE integrates several commercially available codes with modules developed by the authors. All modules share a common user interface and a common relational database. The FORM method9v1 l is used for reliability analysis. Reliability analysis and optimization is integrated with the continuum method of design sensitivity analysis. This integration opened up the opportunity to create an efficient interactive computer environment supporting RBO of large structural systems4,15,16,18.