Prediction of formability of adhesive bonded steel sheets and experimental validation

The main aim of the present work is to predict the formability of adhesive bonded sheets and validate the same with experimental results at different adhesive properties. The tensile and in-plane plane-strain formability tests are carried out to predict the formability of adhesive bonded sheets. The forming limit strains are predicted using thickness gradient necking criterion (TGNC) and effective strain rate criterion (ESRC), and validated with the experimental limit strains. A simulation methodology has been analyzed thoroughly in the present work, and the prediction accuracies are compared and discussed. The results show that the adhesive bonded blanks show improved elongation and forming limit strains as compared to un-bonded base materials with increase in hardener/resin ratio of adhesive. The true stress–strain predictions are accurate as compared to experimental data. There is a moderate difference in adhesive bonded sheets limit strains between predictions and experiments. This may be due to the absence of interface bonding between adhesive and base materials during predictions. The necking criterion, TGNC, shows better prediction as compared to ESRC.