Analysis of the 3d fracture characteristics of CT specimens in the elastic-plastic state

Abstract

In this paper, the void growth ratio parameter V g is applied to describe the 3D fracture characteristics of CT specimens in the elastic-plastic state by means of the finite element method. The effects of stress triaxiality and plastic deformation on V g are analysed in both the r, ϑ plane and the thickness direction z. It is found that the maximum V g always takes place in the midsection of the specimen in the thickness direction; there are two peak values of V g around ϑ = π 4 and ϑ = π − π 4 in the r, ϑ plane, where z equals a constant. This can explain the bluntness of a sharp crack. Generally speaking, the stress triaxiality parameter is the main factor deciding the magnitude of V g but V g strongly depends on the equivalent plastic strain at larger plastic deformation.