Creep failures in heterogeneous materials

TL;DR

This paper investigates creep failure in heterogeneous fiber composites, revealing power law behaviors in creep and failure times, and proposes a predictive model linking primary creep duration to rupture time.

Contribution

It introduces experimental evidence of creep behaviors in heterogeneous materials and a mean-field model explaining the interplay between primary creep and rupture.

Findings

Creep strain and acoustic emission follow power law relaxation and acceleration.

Failure time is proportional to primary creep duration.

Model rationalizes experimental creep and failure behaviors.

Abstract

We present creep experiments on fiber composite materials with controlled heterogeneity. Recorded strain rates and acoustic emission rates exhibit a power law relaxation in the primary creep regime (Andrade law) followed by a power law acceleration up to rupture over up to four decades in time. We discover that the failure time is proportional to the duration of the primary creep regime, showing the interplay between the two regimes and offering a method of rupture prediction. These experimental results are rationalized by a mean-field model of representative elements with nonlinear visco-elastic rheology and with a large heterogeneity of strengths.