Research on creation and application of material models in the rolling process of medium and heavy plate leveler
Mechanical properties model of moderate/high temperature material affects leveling parameters setting. This article establishes the model as well as self-studying in rolling process and simplex optimizes the formulation of material model's deformation resistance. The model is established through this process which has a higher application in the actual production.
Material Model Describing Cyclic Elastic‐Plastic Deformation of Roller Levelling and Straightening Processes
The presented material model describes the elastic‐plastic stress‐strain course of cyclic tension‐compression deformation with variable amplitudes. The result is a hysteresis curve. Each hysteresis curve consists at maximum of three parts. Part I starts on a linear course originating from elastic strain or elastic recovery and ends at a defined point N. When the strain runs past this point, part II then follows as a non‐linear function where the superposition of a logarithmic function with a parabola proved to be in good coincidence with the real material behaviour. When the strain reaches a point T, linear hardening begins as part III. For the application of the model in practice, a file of data from special tests with cyclic tension‐compression deformations is necessary. The material model can be applied as a subsystem in a roller straightening process model. It has been successfully used in practice. The detrimental residual stresses were significantly reduced as well as the straightness of the rails was improved.
SPRINGBACK PREDICTION BY YOSHIDA-UEMORI MODEL AND COMPENSATION OF TOOL SURFACE USING JSTAMP
Authors programmed a subroutine of Yoshida-Uemori model to commercial software LS- DYNA considering Young's modulus change with plastic strain, and then carried out a springback simulation for two stamping parts using solid element and shell element respectively. To make a designed shape and size of a stamping part, a new function for springback reason research and an algorithm for tool surface compensation were proposed and programmed to simulation system JSTAMP. Lastly, a research for springback reason and a compensation for tool surface of underbody cross member panel were performed using JSTAMP.