Fatigue Properties of Fillet Welded Lap Joints of High Strength Steel Sheets for Automobiles

The effect of a concentration of stress at a welded joint on the fatigue limit was investigated from the point of view of the effective design of automotive parts made of high strength hot rolled steel sheets.

The stress concentration at the welded joint was evaluated using FEM analysis and the effect of stress concentration on endurance limit was investigated by fatigue tests using specimens of practical welded joints and specimens with the simulated configuration of welded joints.

It is pointed out that another effect besides stress concentration and residual stress should be considered to evaluate the endurance limits for high tensile strength materials of over 590 N/mm².