Brittle fracture investigation from disc specimen weakened by U-notch in mixed mode I + II

Abstract

In order to study the behaviour of a notch specimen under plane mixed mode I +II, a Brazilian disc specimen weakened by U-notch located at the edge of disc is considered. A high-strength steel material was used for the disc specimen subjected to diametral compressive loading. A local approach represented by strain energy density approach based on determination of mean value of the strain energy density (that is over a given finite-size volume surrounding the highly stressed regions near the notch tip) was utilized. A finite element analysis by cast3m code have been undertaken in order to determine the evolution of the stress intensity factors and averaged strain energy density for different location of notch from the axis of force application. Variations of radius and angle of notch will cause disturbance in the stress field and local energy in the vicinity of the notch tip. The results of finite element computations were expressed as mathematical relations showing the influence of notch position and its radius on stress intensity factors and averaged strain energy density. The reduction of the angle increases the local energy unlike the increase of the radius tends to reduce it.