Research On The Precise Grid Model Construction Method For The Springback Of Auto-Body Panel

Springback is a common physical phenomenon in the metal sheet forming, which affects directly the quality of forming product. In particular, with the application of high strength steel in automobile body manufacturing, the springback problem has become more seriously. At present, the springback control includes process control as well as springback compensation. And the method of springback compensation is usually applied for revising the die surface and making the shape after springback just the same as the design model.Springback compensation generally includes design compensation and secondary reverse scan compensation based on the actual stamping part. Design compensation based on CAE simulation, obtain compensation model through multiple iterations. This approach can fundamentally solve springback problem of automobile panel, but on account that springback is not be calculated accurately by CAE, so reverse scan for actual stamping part is applied to obtain the scanned data, and then compared with design model to obtain the deviation for compensation of die. But the scanned data will be affected by the influence of gravity, so as to make it become distortion.In order to eliminate gravity deformation of springback and accurately obtain the scanned data, in this paper, a method is put out to acquire the accurate grid model containing only springback to improve the precision of reverse compensation, in which deformation caused by gravity is calculated through CAE and the simulation is verified by experiment, then the scanned data and die surface are aligned through optimization and compel deformation, based on it, new grid model containing only deformation caused by springback is constructed by the way of grid mapping and node offset.A method of the accurate grid model containing only springback construction of automobile panel is proposed, and the main work is as follows:1. Because of the stamping part will be affected by the influence of gravity and its scanned data will be distorted, a method is put forth to acquire the accurate grid model containing only springback. At first a CAE simulation is used to calculate gravity deformation, and then the scanned data and die surface are aligned through optimization and compel deformation in order to construct new grid model containing only springback by the way of grid mapping and node offset.2. According to calculating gravity deformation by CAE simulation, a method of experimental verication is proposed.3. Taking the hood inner of a car for example, gravity deformation is calculated by CAE simulation and based on the scanned data of the inner hood, its new grid model containing only springback is constructed.By the comparsion of result between experiment and CAE simulation, we can conclude that the method of this paper can eliminate gravity deformation of the scanned data and construct new grid model containing only springback in order to improve the precision of reverse compensation, which has a certain significance for engineering applications.