表面積拡大率に着目した塑性加工における境界潤滑機構のモデリング

抄録

To improve the accuracy of numerical simulations of plastic forming, it is important to model the friction between the workpiece and the die. Typical friction models commonly used are Coulomb's friction law (τ = μp) under low contact pressure conditions and constant shear stress measurement (τ = mk) under high contact pressure conditions where the surface roughness is plastic deformed. However, it is clear that μ and k depend on changes in surface properties and slip distance (e.g., as the slip distance increases, the friction coefficient should increase due to oil loss) as machining progresses, and there are limitations to using the simplified friction model described above. From this background, this study focused on the change in the surface area expansion rate of the work material and the junction growth model, which is widely known in the field of tribology, to develop a friction model under boundary lubrication conditions. In order to investigate the validity of the proposed model, comparison between the experimental results and the results of a finite element analysis implementing the model were performed.