The effect of T-stress on crack-tip plastic zones under mixed-mode loading conditions

In this paper, the influence of T-stress on crack-tip plastic zones under mixed-mode I and II loading conditions is examined. The crack-tip stress field is defined in terms of the mixed-mode stress intensity factors and the T-stress using William's series expansion. The crack-tip stress field is incorporated into the Von Mises yield criteria to develop an expression that determines the crack-tip plastic zone. Using the resultant expression, the plastic zone is plotted for various combinations of mode II to mode I stress intensity factor ratios and levels of T-stress. The properties of the plastic zone affected by T-stress and mixed-mode phase angle are discussed. The observations obtained on plastic zones variations are important for further fatigue and fracture analyses for defects in engineering structures under mixed-mode loading conditions.