Study On Prediction Model Of Plate Bending Springback

Bending of wide heavy plate is the main feature of many forming process. It is the main forming procedure in the large diameter UOE ripe forming process. The prediction of the deformation after bending then gaining precise calculation of rebound is the key to control the formation quality of thick pad bending.The paper focus on the problem of how to control the shaping quality during the process of bending and deformation of the wide heavy plate based on the theory of the thick plate. In the plate bending calculation based on the theory of the sheet, it usually ignores the influence of the shear deformation. For the bending of thick plate, in order to predict the rebound accurately, it is not only need to adopt corresponding theory of the thick plate, and also need to consider the influence of shear deformation. Revealing the distribution of the strain for the bending of thick plate, and analyzing the effect of the shear stress on the stain field are the predcondition to establish the prediction model of rebound of the thick plate bending considering the shear stress effect.To make sure the accuracy of calculating the rebound, the author started from the three-dimensional pure elasticity problems of heavy plate theory with consideration of the influence of the shear deformation. Based on these two conditions mentioned above, the author makes the appropriate assumptions in the subsequent rebound process. The author assumes the elasto-plastic process of the strain field in the form by using the method of undetermined function with considering the impact of shear deformation, then to decrease the negative influence of the assumption and establish the prediction model of rebound.Using the finite element software to investigate the strain field distribution of the bending of the thick plate and get the key parameters of the prediction model of rebound. And then using the parameters in the following research to make sure the function is correct, then substitute the parameters into the basic equation of the prediction model to calculate the rebound. This method can avoids causing errors from the early function of shear deformation displacement offset.According to the rebound prediction of the thick plate bending problem, the three-point bending experiment device and experiment with different specifications of plates are designed. The three-point bending experiment of different sizes of Q235 steel are proceeded and the rebound is gained. The results of experiment are compared to the theoretical calculation result considering the shear deformation and without considering the shear deformation respectively, and the prediction model of rebound for the bending of thick plate is verified.