An Elasto-Plastic Finite Element Analysis of the Axisymmetrical Tube-Nosing Process with a Conical Tool

摘要

The incremental updated Lagrangian formulation (ULF) of an elasto-plastic finite element computer code into which the extended r_(min) technique has been incorporated in order to handle the contact boundary condition is applied to analysis of the axisymmetric tube-nosing process with a conical tool. A modified Coulomb friction law was adopted to calculate the influence of the coefficient of friction on the tube-nosing process. The effects of the size and the mechanical properties of tubes, the lubricant and the tool semi-angle (φ) on nosing load were studied. The existence of an optimum tool semi-angle φ_m is demonstrated, and it is found that φ_m is decided by the combined effect of the work of friction and of bending at the tool-inlet. The φ_m increases with increasing friction on the punch surface. The non-dimensional forming load increases with the coefficient of friction and is independent of t_o/D_o (t_o: initial thickness; D_o: mean diameter).