PROGRESS AND APPLICATION OF PLASTIC FINITE ELEMENT METHOD IN METALS ROLLING PROCESS

The recent progress of plastic finite element method (FEM) and its application in rolling are introduced, including: (1) progress in rigid plastic FEM theory and application. It deals with the variational principle for rigid-plastic compressible materials, the uniqueness of extreme point of total power rate functional for hot rolling problem, and the examples of solving various rolling processes; (2) elastic-plastic FEM was used to analyze the normal longitude rolling and the special rolling processes, such as wedge rolling, cross wedge rolling and skew rolling; (3) fast-FEM for modeling to control a rolling mill. Now it becomes true that a FEM calculation for one pass flat rolling could be accomplished within 50-100 ms, which means it is possible to meet the requirement of on-line use for the process control to the rolling mill instead the traditional mathematics models; (4) multi-scale FEM simulation for rolling using cellular automata (CA) and FEM. Here the CA was used to simulate the recrystallization and transformation, and the temperature field, stress field and strain field were provided by FEM; (5) using crystal plasticity FEM to simulate the texture evolution during rolling. The crystal plasticity theory was put into the framework of the finite element method, to simulate the plastic deformation process at the crystal scale. An example is given for modeling of rolling Al polycrystal and texture evolution during the deformation; (6) FEM simulation of the crack and inclusion behaviors during rolling. The research works on evolution of cracks on the corner, edge, surface and inside of a workpiece, also for the inclusion by FEM are introduced. Finally, an outlook has been made for the plastic FEM.