Creep failure in heterogeneous materials from the barrier landscape

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.