On the consideration of loading interaction in combined high and low cycle fatigue life prediction

Abstract

Based on the analysis of the test data and Miner's rule, a combined high and low cycle fatigue (CCF) life prediction model considering the loading interaction is established by introducing coupled damage. The coupled damage is determined by multiplying the high cycle fatigue damage and the low cycle fatigue damage by a coupled damage coefficient K. According to the analysis of the test data, the coupled damage coefficient K is positively correlated with the high cycle stress ratio R. In addition, an interaction factor, which reflects the loading interaction effect, is introduced to correct the coefficient K. The CCF experimental data of four materials are employed for model verification and comparison among the proposed model, Miner's rule, and Trufyakov-Kovalchuk model (T-K model). The proposed model exhibits a relatively higher prediction accuracy and is more suitable for predicting the fatigue life of CCF. K E Y W O R D S combined high and low cycle fatigue, coupled damage, fatigue life, loading interaction Highlights 1. A combined fatigue life prediction model is proposed considering loading interaction.2. Coupled damage coefficient is determined through analysis of the test data. 3. The proposed model exhibits a relatively higher prediction accuracy.