Fatigue Life Prediction Methods for Spot Welds in T-Shaped Members under Bending

To develop fatigue life prediction methods for spot welds in thin steel structures such as automobile bodies, bending fatigue tests were made on T-shaped members. Two new prediction methods are proposed. One method is based on loads acting to spot welds, estimated by FEM, and can predict the life from the fatigue data of standard joint specimens such as the tensile shear specimen. Another method uses the fatigue data of a joint specimen having flanges under a combined load, which simulates the stress distribution near a nugget of the member, and makes an accurate life prediction in terms of the measured strain range on the specimen.