An investigation of the effect of the gap values between the overlap portions of the spot-welded pieces on fatigue life

Abstract

In this study, the effect of the space or gap values — between the overlap portions of the spot welded specimens — which is especially important for spot-welded joints subjected to uniaxial in-plane loads, on fatigue life are investigated. In order to do these investigations, a computer programme is developed using ANSYS (version-10) finite-element programme. Numerical results based on the developed computer programme are compared with the experimental results conducted by Sheppard for the validation of the programme and are found to be satisfactory. Fatigue life properties for different type of spot-welded specimens and different gap values are calculated numerically using this developed computer programme with different fatigue-life approaches to see the gap effect on the fatigue life of the spot-welded specimens. It is found that maximum stress and strain values increase, hence fatigue life decrease, with increasing gap values, and this situation is clearer for tensile shear (TS) specimens than modified tensile shear (MTS) ones because of the flanged pieces of the MTS specimens. It is also found that maximum stresses and strains, hence the fatigue-life values, do not change so much for gap values lower than 0.0025 mm.