DESIGN OPTIMIZATION OF LARGE STRUCTURAL SYSTEMS WITH SUBSTRUCTURING IN A PARALLEL COMPUTATIONAL ENVIRONMENT

Design optimization of large structural systems can be attempted throu gh a substructure strategy when difficulties are encountered with conv ergence of such problems. In this strategy the large structure is divi ded into several smaller substructures, and a subproblem is defined fo r each substructure. Solution of the large problem can be obtained ite ratively through repeated solutions of the modest subproblems. Substru cture strategies, in sequential as well as in parallel computational m odes on a GRAY YMP multiprocessor computer, have been incorporated int o the code CometBoards, which is an acronym for Comparative Evaluation Test Bed of Optimization and Analysis Routines for Design of Structur es. Three issues, intensive computation, convergence of the iterative process, and analytically superior optimum, encountered during the imp lementation of substructure optimization into CometBoards have been so lved. Coupling between subproblems as well as local and global constra ints 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.