A modified formula for cyclic compression crack growth model considering compressive load effect

Abstract

Fatigue crack growth under cyclic compression has been confirmed by experiments and widely exists in engineering applications, with the expression of stress intensity factor often serving as milestones. A typical difficulty in calculating the stress intensity factor under cyclic compression is the effect of compressive load on fatigue crack growth. Compressive load effect, resulting in the change of plastic zone and residual stress near crack tip, is a long-term challenge for predicting fatigue crack growth life. We modify the expression of effective stress intensity factor to predict fatigue crack growth life based on the distribution of residual stress, and analyze the effect of load characteristics. It considers the characteristic of material and load, and calculates the driving force of crack growth by integrating the residual stress in plastic zone. In the study of fatigue crack growth experiments under cyclic compression, the modified formula is proved to improve, by comparative analysis, the predictive ability on the whole range of experiment data. Consequently, the modified formula is conducive to calculate the fatigue crack growth.