Load Interaction Effects on Fatigue Crack Propagation in Steels of Varying Strength

摘要

An analytical-numerical model of crack growth retardation in metals subjected to spectrum loading is presented. The model is applied to simulate overload experiments on steels of various strengths. The numerically obtained results are shown to correlate to experimental results quite well. By studying the results it is possible to explain seemingly contradictory results from different sets of experiments. It is shown that higher strength steels may be superior or inferior to lower strength steels in spectrum fatigue, depending on the load sequence used. These results are interpreted in terms of plasticity-induced crack closure. The influence of strain hardening on crack closure levels was assessed.