Online Arithmetic by Fast Finite Element in Strip Rolling

Abstract

Finite element method (FEM) plays a very important role in the simulation and prediction of the parameters of pressure, deformation, temperature and microstructure evolution during rolling process. But online calculation is impossible because of the long time consumed in the FEM calculation of rolling parameters. Fast finite element (FFE) method has advantage of calculation with high precision and fast speed. On the basis of rigid plastic finite element method (RPFEM), the FFE method in strip rolling is developed. Effects of element numbers on calculation time and precision are analyzed. Online arithmetic methods of accelerating convergence and reducing search time are researched, including the combined damped Newton and Brunt method to reduce the one dimensional searchtime; the better initial value can be obtained by adopting improved mid-point integral Newton method; improved Newton method with trust region method and forced positive definite Hessian matrix method are used to reduce the convergence time. In addition, the influence of operating system, hardware and software of computer on the calculating time is also discussed. The FFE online calculation module developed is well used in a hot strip plant.