PARALLEL TRANSIENT DYNAMICS SIMULATIONS - ALGORITHMS FOR CONTACT DETECTION AND SMOOTHED PARTICLE HYDRODYNAMICS

Transient dynamics simulations are commonly used to model phenomena su ch as car crashes, underwater explosions, and the response of shipping containers to high-speed impacts. Physical objects in such a simulati on are typically represented by Lagrangian meshes because the meshes c an move and deform with the objects as they undergo stress. Fluids (ga soline, water) or fluid-like materials (soil) in the simulation can be modeled using the techniques of smoothed particle hydrodynamics. Impl ementing a hybrid mesh/particle model on a massively parallel computer poses several difficult challenges. One challenge is to simultaneousl y parallelize and load-balance both the mesh and particle portions of the computation. A second challenge is to efficiently detect the conta cts that occur within the deforming mesh and between mesh elements and particles as the simulation proceeds. These contacts impart forces to the mesh elements and particles which must be computed at each timest ep to accurately capture the physics of interest. In this paper we des cribe new parallel algorithms for smoothed particle hydrodynamics and contact detection which turn out to have several key features in commo n. Additionally, we describe how to join the new algorithms with tradi tional parallel finite element techniques to create an integrated part icle/mesh transient dynamics simulation. Our approach to this problem differs from previous work in that we use three different parallel dec ompositions, a static one for the finite element analysis and dynamic ones for particles and for contact detection. We have implemented our ideas in a parallel version of the transient dynamics code PRONTO-SD a nd present results for the code running on the Pentium-based Intel Ter aflop machine at Sandia. (C) 1998 Academic Press.