Three-dimensional discontinuous deformation analysis with explicit contact formulation and block-wise multicore CPU acceleration

Abstract

In this study, an explicit three-dimensional discontinuous deformation analysis (3D-DDA) is parallelized. Using explicit contact force circumvents the open-close iteration and makes the global stiffness matrix block-diagonal. Post-judgment of contacts is split into two parts to unify the data access pattern, constant acceleration Newmark method is adopted to guarantee unconditional stability of time integration, and square-root-free Cholesky decomposition is adopted to solve small linear equations efficiently. To exploit the multicore CPU with few changes in code and achieve good modularity, block-wise parallelization is adopted, which can realize the full-stage parallelization with just several lines of OpenMP directives. There is no need to modify block specific algorithms, such as contact detection and block information update, for the proposed parallelization, which results in the most efficient parallelization scheme to date. Correctness and efficiency are validated using several numerical examples. The speed-up ratio of 5.0–6.5 is achieved on an 8-core CPU.