To accurately predict the springback of high strength steel and ultra high strength steel in cold roll forming

two mechanically-measured tests

uniaxial and loading-unloading-loading cycle tests

were introduced to determine the elastic modulus degradation of DP980 with the increase of plastic strain. Considering yield surface and elastic degradation surface

the chord modulus was developed in addition to elastic and plastic strain. The 3D finite element analysis models with eight stands were carried out by the professional COPPA RF and MSC MARC software. The simulation results achieved good agreement with experimental results observed in roll forming for thin cross-section automotive products. It is found that

with the increase of the plastic strain

the value of Young's modulus firstly reduces rapidly

and then slowly

finally tends to a steady value. Degradation of the Young's modulus is found to be 25% from the initial Young's modulus for the saturated value. Compared to the constant elastic modulus

the springback prediction result by using the variable elastic modulus is more accurate.