Analytical characterizations of crack tip plastic zone size for central-cracked unstiffened and stiffened plates under biaxial loading

摘要

Crack tip plastic zone size is affected by biaxial loading and materials, and these effects are studied in the unstiffened and stiffened plates in this paper. By means of three-dimensional finite element method, the characteristics of crack tip stress field and plastic zone are investigated for various biaxial stress ratios. Under small scale yielding conditions, the analytical characterizations of plastic zone size (i.e. improved analytical solutions) are determined in the elastic perfectly-plastic material and strain-hardening materials, respectively. The results show that the biaxial stress ratio has slight influences on stress intensity factor (SIF) and out-of-plane T-stress, but it has significant effects on in-plane T-stress and plastic zone size. The correction factor can reflect the effects of materials on plastic zone size, and the improved analytical solutions are in excellent agreement with numerical solutions under the application ranges. Additionally, the plastic zone size is greatly affected by the hardening performances of materials, but it is slightly influenced by specimen geometry and Young's modulus when SIF and T-stresses are constant.