Experimental study of the effect of disorder on subcritical crack growth dynamics

TL;DR

This study investigates how material heterogeneities, like holes, influence subcritical crack growth in paper, revealing that increased disorder unexpectedly prolongs crack lifetime, contrary to existing models.

Contribution

It provides experimental evidence showing that increased disorder can lengthen crack propagation time, challenging current theoretical predictions.

Findings

Longer crack durations in more ordered materials.

Holes influence crack acceleration and path roughness.

Contradicts models predicting faster crack growth with disorder.

Abstract

The growth dynamics of a single crack in a heterogeneous material under subcritical loading is an intermittent process; and many features of this dynamics have been shown to agree with simple models of thermally activated rupture. In order to better understand the role of material heterogeneities in this process, we study the subcritical propagation of a crack in a sheet of paper in the presence of a distribution of small defects such as holes. The experimental data obtained for two different distributions of holes are discussed in the light of models that predict the slowing down of crack growth when the disorder in the material is increased; however, in contradiction with these theoretical predictions, the experiments result in longer lasting cracks in a more ordered scenario. We argue that this effect is specific to subcritical crack dynamics and that the weakest zones between holes at close distance to each other are responsible both for the acceleration of the crack dynamics and the slightly different roughness of the crack path.