Numerical simulation of ductile crack propagation in weld joint

The ductile crack propagation in the welded joint of turbine rotor steel is simulated by using the finite element method(FEM) with the GTN model,and the curve of loading-displacement and the J-△a crack resistance curves of fracture toughness for base metal(BM),heat-affected zone(HAZ) and weld are simulated by using the GTN model,which fit well with the experiment.The results show that the weld has lowest crack propagation resistance,and the HAZ has the highest resistance.When the initial crack is located at the interface between the BM and HAZ,the crack tends to propagate towards the BM side with lower strength and growth resistance,and its resistance curve is similar to the BM.When the initial crack is located at the interface between the HAZ and weld,the crack growth path deviates from the interface and propagates along the interface,and the resistance curve of interface crack propagation is slightly lower than that of the weld.