Abstract: To investigate the effects of distributed diametral pressures on fracture parameters of a centrally cracked Brazilian disc (CCBD) specimen, the complex potentials theory and weight function method were adopted to derive the mixed-mode I/II fracture parameters of CCBD specimens subjected to five types of distributed loads. Based on the analytical solutions for fracture parameters, the effects of pressure distribution form and pressure distribution angle on stress intensity factors under mode I / II and T stress were investigated. The results show that the pressure distribution form has a remarkable influence on the geometric parameters, YI, YII and T* , with the relatively larger pressure distribution angle and crack length. The YI and T* under pure mode I and the YII under pure mode II both decrease as the pressure distribution angle increases, while the T* under pure mode II increases with an increased pressure distribution angle. When the pressure distribution form is a constant function, the pressure distribution angle has the most obvious effect on geometric parameters, while the degree of the influence reduces greatly for quartic polynomial function. The critical fracture angle under pure mode II is less affected by the pressure distribution form and pressure distribution angle, while the crack length has a significant effect on it.

Key words: distributed contact pressure, centrally cracked Brazilian disc, stress intensity factors, T stress, analytical solutions