Energy absorption behaviour of different grades of steel sheets using a strain rate dependent constitutive model

This study is concerned with the numerical prediction of energy absorption behaviour of different grades of steel sheet. Typical square crush tube is studied owing to its similarity with various automotive structural components useful in crash events. An attempt has been made to characterize the materials for high strain rate behaviour (0.001-800/s) and use a strain rate dependent constitutive model. This constitutive model is validated for multi-axial experiments and further used for predicting the energy absorption and crush efficiency of square tube at different velocities (9.7 m/s, 12.5 m/s, 15.5 m/s). Energy absorption and crush efficiency depends on peak force and steady state crush force. Results show that energy absorption and crush efficiency of DP800 is superior at lower velocity than at higher velocity whereas DP600 is found to have superior crush performance with velocity. CMn440 and IFHS has superior crush efficiency but lower energy absorption compared to DP grades.