The energy dissipation rate-a new tool to interpret geometry and size effects

摘要

This presentation is devoted to geometry and size effects on the crack growth resistance of CT specimens. With a simple numerical model, the main influence factors on these effects can be separated. These are the effects of the in-plane and out-of-plane constraint on the deformation behavior and the locally varying fracture toughness properties of the material along the crack front. Crack growth is modeled for different geometries and sizes assuming that the critical values of the crack tip opening displacement. COD_i, and the critical crack tip opening angle, CTOA_c, remain constant for all geometries and sizes. Crack grwoth resistance curves are plotted in terms of the J-integral and the energy dissipation rate, D. Two types of materials are considered, a low-strength and a high-strength steel.