A Nonlinear Cumulative Fatigue Damage Model and Residual Strength Reduction Analysis for Steel

In this pape, a nonlinear damage evolution equation is derived by the method of Continuum Damage Mechanics (CDM). This equation involves the complete coupling mechanism of stress and damage in the damage developing process. Based on the damage evolution equation, a complete nonlinear cumulative fatigue damage model (NCFDM) is obtained, which takes the nonlinear effect of damage cumulation in one loading cycle and between two loading cycle into account, and the available partial NCFDM is a special case. The degradation law for residual strength and the critical damage value are deduced from the present model.