Determination of Continuum Fracture Mechanics Parameters for Molecular Dynamics Simulations

Abstract

This study is aimed at determination of continuum fracture mechanics parameters such as stress intensity factors, T-stress and higher-order terms, from molecular dynamics simulation performed for copper plate with narrow diamond-like crack. For this purpose, an embedded atom potential (EAM) available in LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator) molecular dynamics (MD) software is utilized to accurately describe mixed-mode crack growth. The stresses calculated from MD method using the virial theorem are used for over-deterministic method for extracting stress intensity factors, T-stress and higher ­ order terms of Williams series expansion. It is shown that the algorithm of the over-deterministic method can be generalized for MD calculations and gives the reasonable value of continuum fracture mechanics parameters. The obtained value of stress intensity factors, T-stresses and higher order terms are compared with the theoretical values for an infinite plate with the central crack under Mode I loading and Mixed Mode loading conditions for several values of the mixity parameter which defines the type of Mixed Mode loading.

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