Prediction of Springback and Final Shape in Stamped Automotive Assemblies: Comparison of Finite Element Predictions and Experiments

This work presents a numerical method for predicting the final shape of stamped automotive assemblies. Each assembly was manufactured by laser trimming and spot–welding two separate stampings together. The panels that represented the ‘inner’ of the automotive assembly were stamped from 1.04mm or 1.63mm AA5754 sheet, while panels representing the ‘outer’ were stamped from 0.93mm AA6111 sheet.

The finite element method (FEM) was used to predict the final shape of the automotive assemblies. For these predictions, finite element models of the forming, individual panel springback, and final assembly springback operations were performed. The laser trimming and spot–welding processes were modelled using pre–processing software.

Experimental validation of the finite element models was undertaken using a coordinate measuring machine (CMM) as well as a non–contact surface digitizing technique. Comparison of the finite element model predictions with the experiments has shown that the influence of the assembly operations such as trimming and spot–welding on final assembly shape can be predicted. These comparisons have also demonstrated the sensitivity of the results to experimental variation.