Elastic forces that do no work and the dynamics of fast cracks

TL;DR

This paper explores the unique forces acting on moving elastic singularities like crack tips in vibrating media, proposing a universal scenario for the dynamic instability of fast cracks that emphasizes the importance of three-dimensional effects.

Contribution

It introduces a new perspective on crack dynamics by highlighting forces orthogonal to crack motion and proposing a universal three-dimensional instability mechanism.

Findings

Elastic forces orthogonal to crack motion are crucial in crack dynamics.

A universal scenario for fast crack instability is proposed.

Three-dimensional effects are essential for understanding crack behavior.

Abstract

Elastic singularities such as crack tips, when in motion through a medium that is itself vibrating, are subject to forces orthogonal to the direction of motion and thus impossible to determine by energy considerations alone. This fact is used to propose a universal scenario, in which three dimensionality is essential, for the dynamic instability of fast cracks in thin brittle materials.