Thermal activation of rupture and slow crack growth in a model of homogenous brittle materials

TL;DR

This paper models slow crack growth in brittle materials as a thermal activation process, providing analytical predictions and simulations that reveal the role of irreversibility and introduce a testable growth length scale.

Contribution

It introduces a thermal activation model for crack growth in brittle materials and compares analytical results with simulations, highlighting irreversibility effects.

Findings

Good agreement between analytical and simulation results

Scaling of energy barrier with stress intensity factor

Identification of a characteristic growth length

Abstract

Slow crack growth in a model of homogenous brittle elastic material is described as a thermal activation process where stress fluctuations allow to overcome a breaking threshold through a series of irreversible steps. We study the case of a single crack in a flat sheet for which analytical predictions can be made, and compare them with results from the equivalent problem of a 2D spring network. Good statistical agreement is obtained for the crack growth profile and final rupture time. The specific scaling of the energy barrier with stress intensity factor appears as a consequence of irreversibility. In addition, the model brings out a characteristic growth length whose physical meaning could be tested experimentally.