Computer Simulation For Sheets Extrusion

In the past industrial production, "trial and error" method has been used to design extrusion dies. This increases the cost drastically because of modifying the design 6f dies and the process conditions of extrusion repeatedly. However, if we exert the CAD/CAE technology on the design of extrusion dies, simulate the flowing state of plastics melt in die, and use computer to modify the design of extrusion dies, which will enhance the successful chances.In this thesis, we simulated the plastic flowing state in sheet dies by the numbers through combining computational fluid dynamics, energetics, polymer rheology and computer technology with the size of dies and technics parameters, which based on the theoretical analysis.The software of ANSYS based on finite element method and MATLAB based on numerical analysis are united in one by author to simulate and analyze the velocity field, pressure field, shear viscosity field, shear stress field and shear rate field for the first time. Meanwhile, we provide the illustrative and visual mesh figure and contour figure. The main interface of program was shown, which made post-processing of simulating result carry out easily.Determinant factors of design in sheet dies-exit uniform thickness and flow rate are discussed thoroughly. For T dies, the effects of the transition length and the number of manifold on exit uniform thickness and flow rate are taken into account. For coathanger dies, we investigated the power law n, pressure gradient A P, manifold angle and the number of manifold to the influence of exit uniform thickness and flow rate. The analysis of temperature field is rather complicated. By simple and suppose, temperature field of T and coathanger dies are simulated. Meanwhile, we compare the distinction of temperature distribution of the two dies.