Role of the sample thickness in planar crack propagation

TL;DR

This study investigates how the thickness of a sample influences planar crack propagation in a disordered elastic medium, revealing thickness-dependent effects on crack morphology and avalanche behavior.

Contribution

It demonstrates that sample thickness introduces characteristic length scales affecting stress transfer and crack morphology, linking to line depinning models and experimental results.

Findings

Thickness induces a crossover in crack front morphology from multi-scaling to self-affine.

Crack avalanche distributions depend on sample thickness and loading mode.

Stress enhancement factors are affected by the sample thickness.

Abstract

We study the effect of the sample thickness in planar crack front propagation in a disordered elastic medium using the random fuse model. We employ different loading conditions and we test their stability with respect to crack growth. We show that the thickness induces characteristic lengths in the stress enhancement factor in front of the crack and in the stress transfer function parallel to the crack. This is reflected by a thickness-dependent crossover scale in the crack front morphology that goes from from multi-scaling to self-affine with exponents in agreement with line depinning models and experiments. Finally, we compute the distribution of crack avalanches which is shown to depend on the thickness and the loading mode.