Applications of the Finite Element Method to Sheet Metal Flanging Operations
This paper summarizes several recently developed finite element models for numerical analysis of stretch flanging operations in sheet metal forming. For flange geometries which can be represented by a ruled surface, the forming operation is shown to be adequately modelled by using an elastic-plastic, in-plane deformation finite element analysis provided that the ruled surface is developable. The obvious advantage of an in-plane model is that numerical solutions can be more easily obtained as compared to those by an out-of-plane model. Calculations for the flanging of a circular tube and a notched stretch flange are discussed in detail. The application of the in-plane model has been recently extended to the case where the ruled surface is non-developable. As an example, calculated strain distributions in a flange formed by twisting are presented. For flange geometries which cannot be represented by a ruled surface, modelling of the forming operation must include out-of-plane deformation and friction contact as well. Numerical results for the forming of an offset flange by using an axisymmetric finite element model were obtained, and compared with experimental data. Effects of the tool friction and material parameters on the forming operation are discussed.
KeywordsSheet Metal Free Edge Circular Tube Sheet Metal Form Load Correction
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