Characteristics of crack front stress fields in three-dimensional single edge cracked plate specimens under general loading conditions

Abstract

In the present article, extensive three-dimensional finite element analyses are conducted for elastic single edge cracked plate (SECP) specimens, which is one of the most widely used specimen for fracture toughness testing. A wide range of geometrical parameters variations are considered including in-plane crack depth to plate width ratio (a/W) and out-of-plane plate thickness to width ratio (t/W). Furthermore, for each three-dimensional specimen, four different crack loading conditions are considered including uniform, linear, parabolic and cubic stress distributions applied on the crack surface. Complete solutions of stress intensity factor, in-plane T-stress (T11) and out-of-plane T-stress (T33) stresses along the edge-crack front are obtained. Characterizations of crack front stress fields using stress intensity factor and T11 and T33 parameters are carried out. By using superposition method, the present solutions enable the calculations of the stress intensity factors, and T-stresses for wide range of a/W,t/W and under generally loading conditions. Application of this method for the determination of these fracture mechanics parameters for other arbitrary loading conditions, are carried out. The combination of the effects of crack depths (a/W), plate thickness (t/W), and loading conditions on the crack front distributions of stress intensity factor, T11 and T33 stress are thus discussed. Solutions obtained will be very useful for analyzing fracture toughness test data for single edge cracked plate specimens with different crack depths (a/W), thickness ratios (t/W), and under general loading conditions.