SEMI-WEIGHT FUNCTION METHOD ON COMPUTATION OF MIXED-MODE STRESS INTENSITY FACTORS

Semi-weight function method was used and developed to solve general plane fracture problems. Two sets of analytical expression of semi-weight functions were obtained. Integral expression of composite stress intensity factors, were obtained from reciprocal work theorem with semi-weight functions and approximate displacement and stress values on any integral path around crack tip. These semi-weight functions satisfy conditions of equilibrium equation, stress and strain relationship, special singularity of displacement near the crack tip and the traction free on the crack surface. The singularity of stress near crack tip is avoided. The approximate values can be calculated from numeric methods. FEA was used to calculate approximate values in this paper. There were no singular elements be used in modeling. With rough mesh size, the semi-weight function method can get more precision result than that from pure FEA with fine mesh size and singular elements on crack tip. The calculation results of applications show that among high precision calculation methods, compared with the weight function method, this method provides applicable analytical expressions of semi-weight functions and in less restrict conditions. Compared with finite element method, it needs fewer amounts of calculation and simple and convenient FEA model.