Numerical modelling of crack tip opening in welded joint

Abstract

Welded joint is of heterogeneous structure with different microstructural regions. To determine the local behaviour of the region measuring crack opening, the problem is to locate the notch tip properly. Simulation of the welding is performed by heating specimens and programmed cooling on different temperatures so as to obtain the microstructure similar to the one in the heat affected zone. Numerical model of stress-strain field around the crack tip based on the finite element method, enables to determine the load for the crack growth with satisfactory accuracy, as is verified by experimental results. The application of this model enables to avoid expensive experiments and instead use numerical simulation to determine the load level that causes crack growth.