A COARSE-GRAINED ATOMISTIC METHOD FOR 3D DYNAMIC FRACTURE SIMULATION

Q Deng and YP Chen, INTERNATIONAL JOURNAL FOR MULTISCALE COMPUTATIONAL ENGINEERING, 11, 227-237 (2013).

In this work, a new coarse-grained (CG) method is presented. The new method combines an atomistic formulation of balance equations and a modified finite element method. Through three numerical examples, we demonstrate that the new method is able to predict the dynamic fracture behavior of crystalline materials. First, the stress wave propagation is simulated through the CG method and the stress response is found to be identical with that of the corresponding atomic-level molecular dynamics (MD) simulation. Then, three-dimensional dynamic crack propagation in a notched thin film under tension is simulated through both CG and MD simulations. Simulation results show that not only the crack propagation paths but also the local and average stresses calculated from CG simulations agree well with that from the corresponding MD simulations. Most importantly, although a large number of degrees of freedoms have been eliminated, the CG models capture the atomic-scale phenomenon such as the dislocation emission and migration accompanied with the crack propagation. In addition, through CG simulations of a plate under impact lading, the CG method is demonstrated to be able to simulate both stable crack propagation problems and the fragmentations of materials under high-strain-rate dynamic loading.

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