Research On Springbcak Compensation For Creep Age Forming Based On Improved Displacement Adjustment Method

With the development of Aeronautics and Astronautics,the requirements on the forming processes of large integral panels continue to grow.Due to its application to the forming of large structural components and the high precision of forming,and the good performance of the material after forming,creep aging forming has been paid more and more attention.However,the components formed by this method still have large springback.The trial and error method which is used as a traditional way to correct the die profile costs a lot of manpower and material resources.In recent years,it has been proved to be a hot research direction that using the finite element method to simulate and optimize the creep aging forming processes of metal structure,and then to guide the practical production.Based on the practical production processes,finite element simulation models of creep age forming for 2324 aluminum alloy were established.The constitutive model of 2324 aluminum alloy was compiled with Fortran language,and was invoked by the finite element model through the software subroutine interface.To reduce the large springback of creep age formed parts,the displacement adjustment method(DA)was used to correct the die profiles.Considering that in the general application processes,the same direction compensations were made for different positions of the components in the DA method,which is not in accordance with the actual directions of the springback displacements.Based on the DA method,influence of the compensation directions on compensation effect was studied,and three typical compensation directions were chosen to make compensations for cylindrical structure components.The results showed that,compared with the parts compensated in same direction,compensations in connection direction and normal direction have the advantage of making the components reach a higher precision with less compensation times.In order to further improve the compensation efficiency and the forming precision of the components after compensation,effect of the compensation amount on the springback was studied.Based on the On-Step DA,Lagrange interpolation polynomial was used to determine the optimal compensation factors for the forming processes of saddle contour.Then the obtained factors were used to correct the die profiles for saddle contour.By comparing with the method in which the compensation factors were a same constant,the results showed that the usage of optimal compensation factors can make the precision of components and the efficiency higher.