Cold-formed steel, as an economical cross-section profile, has been saving resources by optimizing the cross-sectional shape rather than simply increasing the amount of material and improving material performance, which makes it have a wide range of applications and has been widely used in automobiles, aviation, construction, etc. industry.
For profiles formed by three-roll bending, the relative bending radius is relatively large. When calculating the springback of profiles, the mathematical geometric relationship should be combined with the law of springback in mechanics, so that the calculation formula can be more universal. Therefore, in the process of deriving the calculation formula of the three-roll bending springback of the profile, we combined the geometric relationship and the law of springback during plastic bending to calculate the springback of the three-roll bending of the profile.
In the process of cold roll forming, the equivalent stress and strain are mainly concentrated in the bending corner in the transverse direction. In addition, there are certain deformations in the edge and middle part of the sheet. As the rolling progresses, the deformation at the corner of the sheet metal changes from elastic-plastic deformation to plastic deformation; from the characteristics of the stress change at the corner at the node, cold-formation is a process of multiple loading and unloading. Elastic recovery occurs after passing through the rolls; during the cold bending deformation process of the car anti-collision beam, there is a transition zone between the two sets of rolls, and the equivalent stress in the transition zone also reaches a large value, and the sheet metal undergoes plastic deformation in this zone. According to the mathematical geometrical relationship and the stress-strain distribution of three-roll bending forming, the calculation formula of profile three-roll bending springback is deduced, and the process test verification is obtained.