Fast crack propagation by surface diffusion

TL;DR

This paper introduces a continuum theory explaining rapid crack growth via surface diffusion, predicting steady-state velocity saturation, tip blunting, and potential tip splitting under high tension.

Contribution

It provides a novel theoretical framework for fast crack propagation that self-consistently determines crack tip radius and includes instability mechanisms.

Findings

Predicts crack velocity saturation below Rayleigh speed

Shows tip blunting during fast crack growth

Identifies potential tip splitting instability

Abstract

We present a continuum theory which describes the fast growth of a crack by surface diffusion. This mechanism overcomes the usual cusp singularity by a self-consistent selection of the crack tip radius. It predicts the saturation of the steady state crack velocity appreciably below the Rayleigh speed and tip blunting. Furthermore, it includes the possibility of a tip splitting instability for high applied tensions.