A simple model for viscoelastic crack propagation

TL;DR

This paper introduces a simple model for viscoelastic crack propagation that accounts for energy dissipation far from the crack tip, showing semi-quantitative agreement with more detailed theories.

Contribution

It presents a straightforward theory that predicts crack propagation energy without detailed near-tip stress field modeling, applicable to both opening and closing cracks.

Findings

Simple model aligns with detailed stress-based theories

Energy dissipation occurs far from the crack tip

Closing cracks require energy dissipation in the process zone

Abstract

When a crack propagate in a viscoelastic solid energy dissipation can occur very far from the crack tip where the stress field may be very different from the $r^{-1/2}$ singular form expected close to the crack tip. Most theories of crack propagation focus on the near crack-tip region. Remarkable, here I show that a simple theory which does not account for the nature of the stress field in the near crack-tip region result in a crack propagation energy in semi-quantitative agreement with a theory based on the stress field in the near crack-tip region. I consider both opening and closing crack propagation, and show that for closing crack propagation in viscoelastic solids, some energy dissipation processes must occur in thecrack tip process zone.