Design optimization of large structural systems with substructuring in a parallel computational environment

Abstract

Design optimization of large structural systems can be attempted through a substructure strategy when difficulties are encountered with convergence of such problems. In this strategy the large structure is divided into several smaller substructures, and a subproblem is defined for each substructure. Solution of the large problem can be obtained iteratively through repeated solutions of the modest subproblems. Substructure strategies, in sequential as well as in parallel computational modes on a CRAY YMP multiprocessor computer, have been incorporated into the code CometBoards, which is an acronym for Comparative Evaluation Test Bed of Optimization and Analysis Routines for Design of Structures. Three issues, intensive computation, convergence of the iterative process, and analytically superior optimum, encountered during the implementation of substructure optimization into CometBoards have been solved. Coupling between subproblems as well as local and global constraints grouping are essential for convergence of the iterative process. The substructure strategy can produce an analytically superior optimum different from what can be obtained by regular optimization. For the problems solved, substructure optimization in a parallel computational mode made effective use of all assigned processors.