Transitions in dynamic stress states due to crack initiation in a single crystal

Abstract

A B S T R A C T The effect of crack initiation on the dynamic stress states in a single crystal material is simulated using molecular dynamics methods. In Process, we examined if the dynamic virial stress measure capture structure vibration characteristic. The material is modeled using atomic state representative volume elements with both finite and infinite boundaries. The elastic response of the material is the result of atomic interaction modeled using embedded atom method (EAM) force potentials and idealized single crystal lattice geometries. Convergent initial equilibrium states are obtained by heating the material ensemble with slow heating rates. From the numerical simulations temperature dependent properties of the gold are determined. Frequency spectrum of virial stress and its kinetic and potential components are obtained. Crack initiation is modeled by selectively removing force interactions between atoms on the crack plane. The transition in the dynamics stress states are observed in the frequency domain. Frequency and amplitude shifts as evident in the frequency spectrum plots, show the loss in the stiffness (shift in the fundamental frequency) of the material.