Fatigue evaluation on the effect of impact pits with various impact conditions by a CDM‐based approach

Abstract

This work aims to quantitatively evaluate the influence of the impact velocity, location, and angle of a spherical foreign object on fatigue lives. A continuum damage mechanics (CDM)–based fatigue approach is proposed to evaluate the fatigue behavior. The experiments on a cast AlSi7Mg1 aluminum alloy with a low‐velocity impact pit are used to validate the proposed fatigue model. The comparison between the predicted lives with the experimental data indicates an excellent agreement. Based on the proposed model, the effects of various impact velocities, locations, and angles are investigated. It is found that the velocities have negligible influence on the fatigue life in low‐velocity impact cases once the pit depth is the same. The most dangerous impact location for 90° normal impact cases is inferred to be a distance away from the boundary surface. The 45° transverse impact close to the boundary is different from other studied oblique impacts and has a longer life than the corresponding normal impact. This study uses a feasible method to predict the effects of different impact conditions and provides useful guidance for engineering applications.