The Influence Of T-stress On Fracture In Engineering And Its Numerical Calculation Methods

In fracture mechanics, the crack analysis is mainly concentrated on stress field near the crack tip. For the stress of crack tip region, traditional fracture mechanics only considers the singular term. T-stress, the first term of nonsingular terms in Williams expansion and parallel to the direction of crack surface, can be used to describe the stress of crack tip. Based on linear elastic fracture mechanics, except the singular stress intensity factor, take into account the nonsingular T-stress to describe the stress field of crack tip. Then, accuracy of stress field near the crack tip can be improved, and the theoretical prediction values can be more approximated to the experimental results. The paper studies the influence of T-stress on engineering fracture in theory, and its calculation methods. The following aspects are included:1?Combining with the theory of fracture mechanics, describe the crack-tip stress field. And by means of the criterion of maximum circumferential stress as a fracture criterion, summarize the theory of Extended Finite Element Method to simulate the crack extension.2?Analyze T-stress in theory. According to the Airy stress function, deduce the stress field of crack tip about mode I and II crack, and study the influence on fracture in engineering. Through the theoretical analysis of T stress, study its influence on engineering fracture. Mainly includes: the influence on the shape and size of plastic zone in crack tip; the influence on the stability of crack path; the influence on the calculation accuracy of mode I and II stress intensity factor; the influence on crack initiation and propagation angle.3?Provide an overview of several numerical methods to solve the T stress. Take mode I facture of an unilateral crack tensile plate for example, verify the availability of green function method solving T stress. Consequently, according to green function method, solve the T stresses and make graphics about an disk with a internal crack, an rectangular plate with a center crack, an rectangular plate with a single edged crack, an rectangular plate with bilateral crack.