Rupture Modeling of Spot Welds Suitable for Crash FE Analysis in Vehicle Development Process

This paper describes the development of rupture modeling of spot welds suitable for crash FE analysis in vehicle development process. The authors presented a detailed spot weld rupture model called ‘spider web model’ in Toyota and confirmed that it closely correlates with actual full vehicle crash test results. Although, the spider web model is accurate, extensive effort is required to construct the model. Also, the spider web model can only simulate the nugget pullout mode of spot weld rupture and it cannot simulate the nugget fracture mode observed in the ultra high strength steels. Many investigations have been conducted on spot weld rupture modeling using mesh free connection which is suitable for vehicle development process. However, these models have not been validated with a full vehicle level test results. A spot weld rupture model using beam element and mesh free connection, which can simulate both nugget pullout and nugget fracture mode of spot weld rupture, has been developed. Full vehicle level FE analysis is conducted to confirm the prediction accuracy of developed spot weld rupture model. Results show that spot weld rupture locations and number of ruptured spot welds closely correlate with actual crash test results.