Research on springback mechanism of TA2/Q235B composite plate in roll forming

The bimetallic composite plate has the mechanical properties of two different materials, and the springback mechanism is more complex than that of the single metal plate in the roll-forming process. In this paper, the springback mechanism of the composite plate was studied utilizing finite element simulation and experiment. The concept of the springback factor was proposed, representing the distribution state of internal strain of composite plate as the leading cause of springback change under different working conditions. Affected by the structural characteristics of the composite plate and the roll shape, the composite plate may have both positive and negative springback regions, and the final springback depends on the competitive relationship between the two. The influence mechanism of the total thickness, thickness ratio, and forming angle on the springback was analyzed in depth. The results show that the springback angle of the composite plate gradually shifts from positive to negative when the total thickness increases from 3 mm to 7 mm, and the springback angle generated at 7 mm is the smallest. The springback angle of the composite plate progressively rises as the thickness ratio advances from 0.1 to 0.5, and the springback angle is the smallest when the thickness ratio is 0.1. The springback angle of the composite plate increasingly shifts from positive to negative when the forming angle grows from 10° to 30°, and the springback angle is the smallest at 15°. The prediction model between different influencing factors and springback angle is established by the response surface method, and the model's accuracy is verified by simulation and experiment. According to the model, the strength of the factors affecting the springback angle is forming angle > total thickness > thickness ratio, and the forming angle and total thickness factors significantly affect the springback angle.