Massively Parallel Molecular Dynamics Simulations of Two-dimensional Materials at High Strain Rates

Abstract

Large scale molecular dynamics simulations on a massively parallel computer are performed to investigate the mechanical behavior of 2-dimensional materials. A model embedded atom many-body potential is examined, corresponding to “ductile” materials. A parallel MD algorithm is developed to exploit the architecture of the Connection Machine, enabling simulations of > 106 atoms. A model spallation experiment is performed on a 2-D triagonal crystal with a well-defined nanocrystalline defect on the spall plane. The process of spallation is modelled as a uniform adiabatic expansion. The spall strength is shown to be proportional to the logarithm of the applied strain rate and a dislocation dynamics model is used to explain the results. Good predictions for the onset of spallation in the computer experiments is found from the simple model. The nanocrystal defect affects the propagation of the shock front and failure is enhanced along the grain boundary.

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Acknowledgments

This work (LAUR # 92-3737) was performed at Los Alamos under the auspices of the University of California, U.S. Department of Energy Contract No. W-7405-ENG-36. NJW acknowledges the support of the NSF-PYI program. The computational resources, provided by the Advanced Computational Laboratory of Los Alamos National Laboratory, are gratefully acknowledged.

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Correspondence to Norman J. Wagner.

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Wagner, N.J., Holian, B.L. Massively Parallel Molecular Dynamics Simulations of Two-dimensional Materials at High Strain Rates. MRS Online Proceedings Library 291, 91–96 (1992). https://doi.org/10.1557/PROC-291-91

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