Ultimate Strength and Failure Mechanism of …（极限强度和破坏机理的u2026）.pdf

Ultimate Strength and Failure Mechanism of Resistance Spot Weld Subjected to Tensile, Shear, Yuh J. Chao or Combined Tensile/Shear Loads Mem. ASME Department of Mechanical Engineering, University of South Carolina, Strength tests were performed to reveal the failure mechanisms of spot weld in lap-shear Columbia, SC 29208 and cross tension test samples. It is shown the while the lap-shear (cross tension) sample e-mail: chao@sc.edu is subjected to shear (normal) load at the structural level the failure mechanism at the spot weld is tensile (shear) mode at the materials level. Based on the observed failure mechanism, stress distribution is assumed and related to the far field load for the lap- shear and cross tension test samples. It appears that the failure load of the cross tension sample is 74 percent of the lap-shear sample based on the classical von Mises failure theory. The theoretical model is further extended to the mixed normal/shear loading condition. Data from strength tests as well as finite element numerical method are used to validate the model. Finally, the utility of the model in accessing the failure strength of spot