Study of the branching instability using a phase field model of inplane crack propagation

TL;DR

This paper uses a phase field model to investigate the dynamic branching instability in in-plane crack propagation, revealing critical speeds and the importance of 3D effects, with results aligning with theory and experiments.

Contribution

It introduces a phase field simulation approach to study in-plane crack branching, highlighting the critical speed and the necessity of 3D modeling for full understanding.

Findings

Critical branching speed is about 0.48 times the shear wave speed.

Finite interface effects are negligible in large systems.

Simulation results agree with theoretical and experimental data.

Abstract

In this study, the phase field model of crack propagation is used to study the dynamic branching instability in the case of inplane loading in two dimensions. Simulation results are in good agreement with theoretical predictions and experimental findings. Namely, the critical speed at which the instability starts is about $0.48 c_s$. They also show that a full 3D approach is needed to fully understand the branching instability. The finite interface effects are found to be neglectable in the large system size limit even though they are stronger than the one expected from a simple one dimensional calculation.