Solution of transient nonlinear structural dynamics problems using the modified iterative group-implicit algorithm

In this work, the Modified Group Implicit (MIGI) algorithm, a domain-by-domain solution algorithm is extended for the solution of nonlinear structural dynamics problems concurrently. In a transient nonlinear analysis, nonlinear iterations are necessary to satisfy the dynamic equilibrium along with the MIGI iterations. These two iterations may be combined and performed in a single process loop or they may be isolated. Both schemes have been implemented and tested. It is found that the isolation of the iterations produces a more efficient scheme than the one resulting from combination of the two loops. A fully nonlinear transient analysis of a 20- storey model building is carried out, using the separate loop scheme, on an IBM SP multi-computer and a network of SUN workstations. Excellent accuracy in the solution has been obtained with significant speedup of the computations.