Mixed-discrete reliability-based optimization of structural systems under multi-loading conditions

摘要

The paper deals with application of the so-called transformation optimization techniquernto solve mixed (discrete-continuous) Reliability-Based Optimization (RBO) problem of truss structures.rnThe mixed RBO problem is formulated as the minimization of structural volume subjected tornthe constraints on the values of reliability indices determined by FORMapproach. The cross-sectionalrnareas of truss bars and coordinates of the specified truss nodes are considered as discrete and continuousrndesign variables, respectively. The specified allowable reliability indices are associated with limitrnstates in the form of the admissible displacements of the chosen truss nodes and admissible stress orrnlocal buckling of the elements. Both the componental and system reliability indices are considered.rnThe transformation method allows to transform the mixed optimization problem into the continuousrnone and then to use one of the standard nonlinear programming algorithms. The numerical examplesrnof plane cantilever truss is used to illustrate the proposed methodology of solution. Obtained resultsrnare compared and appropriate conclusions are drawn.