Fatigue crack propagation between holes and particles

Abstract

This study investigates the behaviour of a fatigue crack, propagating between holes or particles. These inhomogeneities are found to play a significant role on the fatigue propagation behaviour. The study is performed by simulations, both experimentally and numerically. The experiments show that holes or partly debonded particles on the average accelerate the crack growth, even though they may exert a decelerating effect, due to shielding, during some phase of a crack tip passage between the holes or particles. Besides debonding, a high material stiffness ratio between matrix and particles also tends to accelerate fatigue crack growth. The numerical simulations are able to explain the essential experimental results quite satisfactorily, even though a few seemingly anomalous experimental results are still not convincingly explained.