Creep failure in heterogeneous materials from the barrier landscape

TL;DR

This paper studies creep failure in heterogeneous materials like paper, combining experiments and models to understand the statistical behavior and predictability of failure times under constant load.

Contribution

It introduces a fiber bundle model in a disordered landscape that captures the complex statistics and history effects observed in creep failure experiments.

Findings

Log-normal statistics in event times

Non-Markovian behavior in failure processes

Power-law relationship between event times and failure time

Abstract

Stressed under a constant load, materials creep with a final acceleration of deformation and for any given applied stress and material, the creep failure time can strongly vary. We investigate creep on sheets of paper and confront the statistics with a simple fiber bundle model of creep failure in a disordered landscape. In the experiments, acoustic emission event times $t_j$ were recorded, and both this data and simulation event series reveal sample-dependent history effects with log-normal statistics and non-Markovian behavior. This leads to a relationship between $t_j$ and the failure time $t_f$ with a power law relationship, evolving with time. These effects and the predictability result from how the energy gap distribution develops during creep.