이종판재의 U-bending 스프링백 거동 특성

For weight reduction and improvement of efficient of the car, the demand of the forming production using high strength steel is increased, Necessity about concurrent formining of the dissimilar material double layered sheet is mentioned. In case of high stregh steel, spring-back occurs significantly at the forming process, this is influenced by the complex factors of the stiffness of material, sheet thickness, the geometry shape of die and punch. In this study, At the concurrent forming of dissimilar yield stress double layered sheet, U-bending experiment was performed to understand the formability regarding variable of bending angle of the die and punch. As a result, confiimed proved formability regarding spring-back is decreased compared with single steel at the same bending angle during the concurrent forming a dissimilar material double layered sheet, And spring-back is decreased with the increase in angle based on the bending angle of 90, It was Confirmed that can increase the formability by geometry shape of the die and punch.