A Dynamical Coefficient Mechanics Model for Fatigue Crack Growth under Constant Amplitude Loading

Almost all load bearing components usually experience variable amplitude loading (VAL) rather than constant amplitude loading (CAL) during their service lives. Although many models have been proposed on this subject, but life prediction under these complex situations is still under constant improvement. The present study aims at evaluating residual fatigue life under CAL due to application of the inertial effect coefficient by adopting a dynamical coefficient mechanics (DCM) model. The proposed model was illuminated based on static fracture mechanics and the correlative problems of dynamic fracture mechanics were changed into ones of linear elastic fracture mechanics (LEFM) by d'alembert's principle. A new expression for the fatigue crack propagation (FCP) rate has thus been derived. The expression was verified by using couple samples from published experimental results and is in good agreement with the test results.