Weld failure/separation in vehicle body structures subjected to impact condition may results in component instability and thus reduced energy absorption. A new finite element method has been developed for modeling the behavior of spot welds in elastic, plastic and separation stages. This method can be used to simulate weld failure in vehicle crash analysis using a failure formulation derived from coupon test results. It is a generalized method and is intended to be applicable to any combination of the weld design parameters such as thickness, materials, coating and impact speed. The method has been validated on the crash tests on straight and S-type rails with a hat section. The CAE prediction based on the modeling procedure correlates well with the test results for all the rail crush cases. The welds are modeled using the beam-type spring element with the newly developed weld damage parameters. The baseline curves for the spring element and the detailed projection equations developed are provided in this paper. The presented method and major effect curves from the testing can also benefit the spot weld design and specification development.
