SHORT-FATIGUE-CRACK GROWTH-RATE MODELING BASED ON THE J-INTEGRAL AS THE CONTROLLING PARAMETER

The local plasticity around the short fatigue crack tip fails to satisfy the basic assumption of linear-elastic fracture mechanics, which will lead to strong nonlinearity between da/dN and stress field strength indicator. Therefore, the elastic-plastic fracture mechanics parameter J-integral is employed to consider the non-uniform stress field. To this end, the in-situ observation system is set up to monitor and measure the short fatigue growth behavior in real time. The indicator ΔJ is analyzed based on recorded three-dimensional geometric parameters of the crack. The quantitative relationship is established to model the short fatigue crack’s growth rate.