A spatial decomposition parallel algorithm for a concurrent atomistic-continuum simulator and its preliminary applications

This paper presents the development of a spatial decomposition parallel algorithm and its implementation into a concurrent atomistic-continuum (CAC) method simulator for multiscale modeling of dislocations in metallic materials. The scalability and parallel efficiency of the parallelized CAC are tested using up to 512 processors. With a modest computational resource, a single crystalline f.c.c. sample containing 10: 6 billion atoms is modeled using only 4; 809; 108 finite elements in a CAC model at a fraction of the cost of full molecular dynamics (MD). The simulation demonstrates a nearly ideal scalability of the newly parallelized CAC simulator. The parallel efficiency of the newly parallelized CAC is shown to be higher than 90% when using 512 processors in the high performance computing cluster at Iowa State University. This parallel efficiency is comparable to the state-of-the-art atomistic simulator. Moreover, the newly parallelized CAC simulator employing a uniform coarse mesh is capable of capturing important atomistic features of dislocations, including dislocation nucleation, migration, stacking faults as well as the formation of Lomer-Cottrell locks, in a billion-atom system. The spatial decomposition-based parallelization algorithm developed in this work is general and can be transferable to many other existing concurrent multiscale simulation tools. Published by Elsevier B.V.