Fatigue life prediction in AlMgSi1 lap joint weldments

The fatigue behaviour of an AlMgSi1 alloy lap welded joint and the improvement in fatigue strength due to post-weld heat treatment were investigated. Two series of fatigue tests were performed: one in as-welded specimens and another in heat-treated specimens. The prediction of crack initiation life under a plane strain condition was made based on the local strain approach using Morrowʹs modified equation. The local inelastic stresses and strains at the weld toe were calculated for the heat-treated specimens using three methods: Neuber, Glinka and finite element analysis. The accuracy of the different methods were evaluated and discussed.