Nonequilibrium brittle fracture propagation: Steady state, oscillations and intermittency

TL;DR

This paper develops a minimal dynamical model for 2D brittle fracture propagation, explaining steady, oscillatory, and intermittent behaviors observed in materials, and links these to material properties and noise effects.

Contribution

It introduces a novel minimal model that captures complex fracture dynamics, including oscillations and intermittency, based on a non-quasistatic stress evolution framework.

Findings

Steady and oscillatory fracture propagation depend on a key material parameter.

Noise induces intermittency and quasi-periodic fracture behaviors.

The model explains experimental observations in polymers and amorphous brittle materials.

Abstract

A minimal model is constructed for two-dimensional fracture propagation. The heterogeneous process zone is presumed to suppress stress relaxation rate, leading to non-quasistatic behavior. Using the Yoffe solution, I construct and solve a dynamical equation for the tip stress. I discuss a generic tip velocity response to local stress and find that noise-free propagation is either at steady state or oscillatory, depending only on one material parameter. Noise gives rise to intermittency and quasi-periodicity. The theory explains the velocity oscillations and the complicated behavior seen in polymeric and amorphous brittle materials. I suggest experimental verifications and new connections between velocity measurements and material properties.