Simulation of the Crack Growth Under Mixed-mode Loading: Fracture Criteria and Molecular Dynamics Approach

Abstract

The crack propagation direction angle is investigated by the use of two approaches. The first one is based on the classical mathematical theory of brittle fracture and the Williams series expansion of the stress field at the vicinity of the crack tip. The second approach is based on the molecular dynamics method. Atomistic simulations of the central crack growth process in a plane medium using Large-scale Molecular Massively Parallel Simulator (LAMMPS), a classical molecular dynamics code, are performed. The inter-atomic potential used in this investigation is Embedded Atom Method (EAM) potential. The specimens with initial central crack were subjected to Mixed-Mode loadings. The simulation cell contains 400000 atoms. The crack propagation direction angles under different values of the mixity parameter in a wide range of values from pure tensile loading to pure shear loading in a wide diapason of temperatures (from 0.1 К to 800 К) are obtained and analyzed. It is shown that the crack propagation direction angles obtained by molecular dynamics method coincide with the crack propagation direction angles given by the multi-parameter fracture criteria based on the strain energy density and the multi-parameter description of the crack-tip fields.