PRECONDITIONED KRYLOV EQUATION SOLVERS IN ELASTOPLASTIC BOUNDARY-ELEMENT ANALYSIS

Nonlinear elastoplastic boundary element analysis (BEA) involves an al gebraic subproblem requiring the solution of dense nonsymmetric matrix equations with an evolving right hand side vector. When multiple righ t hand side vectors are present, direct matrix triangular factorizatio n techniques have been the compelling choice, amortizing the work of a single matrix factorization over the sequence of multiple fast 'solut ions' of the resulting triangular systems. Recently, the superior perf ormance of preconditioned Krylov equation solvers in linear BEA has al so been documented. In this paper, the superior performance of precond itioned Krylov equation solvers is shown to be extendable to elastopla stic BEA. This is accomplished by exploiting the strategic reuse of th e preconditioner, its factorization, and the Krylov vectors computed i n the solution for the first right hand side vector, in the subsequent solution of matrix equations with multiple 'nearby' right hand side v ectors. The details associated with this strategy are given, and the c omputer resources required in three dimensional elastoplastic BEA are used to quantify the computational efficiency associated with this new algorithm.