A new method for cyclic crack-tip plastic zone size determination under cyclic tensile load

This paper presents a new method to determine the cyclic crack-tip plastic zone size (CTPZS) in the center cracked plate subject to cyclic tensile load. The maximum crack opening displacement (MCOD) and the variable quantity of MCOD (VMCOD) are used to estimate cyclic CTPZS in this method. Based on the series of calculation results by finite element analysis, an explicit expression of cyclic CTPZS versus MCOD and VMCOD is fitted by the least square method. The expression enables to eliminate the influences of crack geometry, plate sizes, elastic modulus, yield stress, plane state, stress ratio, overload ratio and load sequence. Therefore, the presented method is suitable for center cracked finite plate models with different material under cyclic tensile load.