Structural Analysis Methodology for Space Deployable Structures using a High Performance Parallel Nonlinear Finite Element Solver

摘要

The Sierra Solid Mechanics computational platform is evaluated for simulating the deployment of large space structures. Sierra is a suite of nonlinear finite element, multiphysics codes developed by Sandia National Laboratories to exploit parallel computing environments. Sierra includes implicit and explicit nonlinear finite element solvers with frictional contact, geometrically nonlinear large motions, and material nonlinearity. This paper examines the functionality, performance and scalability of Sierra using a set of deployable space structures benchmark problems that embody the key phenomena in the structural concepts of interest. The focus is on comparing the implicit and explicit solvers for these benchmark problems. In the absence of contact, the implicit solver is found to be as much as two orders of magnitude faster than the explicit solver, depending on the number of processors. This is due to the low velocities inherent in these benchmarks. Under contact, the efficiency of the implicit solver is shown to depend on the contact velocities and on the stiffness of the contacting parts. For sufficiently low rates, and with proper selection of a key augmented lagrangian scale factor, the implicit solver is found to be preferred over the explicit solver during contact as well. These results motivate a proposed hybrid approach for large scale simulations that alternates longer periods of implicit solution with shorter periods of explicit solution when necessary.