Young's Modulus Decrease After Cold Forming in High Strength Steels: an Investigation into the Mechanism Using Bake Hardenable Steel

The aim of this work is to know more about the underprediction of springback in numerical simulation of sheet metal forming. There are a lot of factors which influence the accuracy of springback with numerical simulation. One factor responsible for the inaccurate springback prediction is the assumption of constant Young?s modulus in FE analysis. Young?s modulus, however, is found to decrease during plastic deformation. Therefore, an accurate model is needed to be implemented in FE analysis which can predict the decrease in Young?s modulus. With passage of time, Young?s modulus is found to restore to its initial value. The present study focuses on this aspect of springback prediction. Bake Hardenable (BH) steel has been selected to investigate the degradation and recovery in Young?s modulus. The decrease in Young?s modulus and its recovery has been measured experimentally by two methods i.e. the dynamic method (Impulse Excitation Technique) and a static method (Tensile Test).