Computer simulation of fatigue under diametrical compression

TL;DR

This paper uses computer simulations of a discrete element model to study fatigue fracture in disordered materials under diametrical compression, revealing power-law lifetime behavior and the emergence of a fatigue limit influenced by healing.

Contribution

It extends a 2D fracture model to include fatigue mechanisms and healing, providing insights into micro- and macro-level fracture development under cyclic loading.

Findings

Lifetime shows power-law behavior at intermediate loads

Healing extends lifetime and introduces a fatigue limit

Simulation results qualitatively agree with experimental data

Abstract

We study the fatigue fracture of disordered materials by means of computer simulations of a discrete element model. We extend a two-dimensional fracture model to capture the microscopic mechanisms relevant for fatigue, and we simulate the diametric compression of a disc shape specimen under a constant external force. The model allows to follow the development of the fracture process on the macro- and micro-level varying the relative influence of the mechanisms of damage accumulation over the load history and healing of microcracks. As a specific example we consider recent experimental results on the fatigue fracture of asphalt. Our numerical simulations show that for intermediate applied loads the lifetime of the specimen presents a power law behavior. Under the effect of healing, more prominent for small loads compared to the tensile strength of the material, the lifetime of the sample increases and a fatigue limit emerges below which no macroscopic failure occurs. The numerical results are in a good qualitative agreement with the experimental findings.