EFFECT OF T-STRESS ON MODE-I CRACK-GROWTH RESISTANCE IN A DUCTILE SOLID

An elastic-plastic crack growth model, with a traction-separation law specified on the crack plane to characterize the fracture process, is used to study the effect of the non-singular T-stress, acting parallel to the crack plane. The work of separation per unit area and the peak normal stress are the two main parameters used to characterize the fr acture process, and crack growth resistance curves are calculated nume rically for a number of values of the peak stress to initial yield str ess ratio, and for different levels of strain hardening. Small-scale y ielding in plane strain is considered with the remote field specified by a constant value of the T-stress, applied initially, and an increas ing magnitude of the mode I stress intensity factor. It is shown that the predicted T-stress dependence of the fracture toughness during cra ck growth is qualitatively similar to experimental observations, even though the experiments go beyond small-scale yielding.