Prediction of fretting fatigue crack initiation location and direction using cohesive zone model

Contact stresses distributions may substantially reduce the fatigue life of components subject to fretting, leading to early unexpected failures. Accurately predicting the components lives is, therefore, an important topic to be addressed, in particular from a design point of view. This topic has received great attention in the past decades and several numerical tools that better estimate these components lives have been proposed. In this paper, the focus is in the crack initiation phase. At this stage, it is important to correctly predict the crack initiation location and orientation, which is often achieved by using critical plane approaches. Instead, the use of cohesive zone model (CZM) as an alternative approach to accurately estimate those parameters is investigated. Cohesive zone model as well as two of its common initiation criteria, namely quadratic traction-separation criterion and maximum nominal stress criterion, are used to study crack initiation location and orientation under fretting conditions. Our results are compared with the traditional critical plane approaches and with experimental data, suggesting that cohesive approaches can accurately be used in crack initiation prediction.