Influence of fracture incubation time on dynamic crack propagation in brittle solids

Evgeny Shilko,Aleksandr Grigoriev,V Fomin,L Placidi

doi:10.1051/epjconf/201922101013

Abstract

The paper is devoted to theoretical study of the longitudinal shear (mode II) crack unstable growth dynamics in brittle materials. We considered two main regimes of the dynamic propagation of the crack (sub-Rayleigh and supershear) and their implementation conditions. The research was carried out by computer simulation with the Movable Cellular Automaton method, using the generalized kinetic fracture model, which takes into account the finite duration of local fracture (fracture incubation time). It is shown that the fracture incubation time is a key parameter, which determines the transition conditions of the shear crack growth process from the sub-Rayleigh regime to supershear.

Highlights

One of the topical issues of the modern fracture mechanics is determination of regularities and identification of conditions for the realization of possible dynamic propagation regimes for longitudinal shear crack in brittle materials [1,2,3]
Within the framework of the classical linear elastic fracture mechanics, the unstable shear crack growth rate in a brittle material is determined by the equivalent stress value at the crack tip and is limited above by the Rayleigh wave speed value VR
We modeled the process of longitudinal shear crack propagation in a 2D sample, which consists of two finite thickness plates with the same mechanical properties connected by an interface (Fig. 1)

Summary

Introduction

One of the topical issues of the modern fracture mechanics is determination of regularities and identification of conditions for the realization of possible dynamic propagation regimes for longitudinal shear crack in brittle materials [1,2,3]. Within the framework of the classical linear elastic fracture mechanics, the unstable shear crack growth rate in a brittle material is determined by the equivalent stress value at the crack tip and is limited above by the Rayleigh wave speed value VR. In the framework of such models, it is assumed, as a rule, that the time duration of the local fracture process is negligible. This simplification is not fundamental while we consider slow processes; it begins to have a significant impact on the modeling results at process rates comparable to the elastic wave velocities in the material

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