Numerical Simuiation For Squeeze Casting During Filling And Solidification Processes Based On Magnesium Alloy

Higher demand for light weight of components has been proposed in aviation, aerospace, automobile and other areas. Magnesium alloy has attracted much attention as a light metal structure material. We can get high quality parts which have exquisite microstructure, good physics performance and smooth surface because the liquid metal is solidificated under pressure. The squeeze casting of magnesium alloy has the broad development prospect. With the rapid development of the computer techniques, numerical simulation technique is increasingly becoming an important support and complement to experiment techniques in optimizing the technological design, shortening the trial-production periods of the product, reducing the cost, and insuring the product quality and properties. Therefore, it is significant to simulate the filling and solidification processes of squeeze casting. The main contents are as follows.(1) The mathematical model and finite difference method are discussed. Based on the FDM method, we develop the numerical calculation program. This program is used to calculate the filling processes of squeeze casting. The influence of different speeds of plunger on quality is analyzed.(2) In this paper, Alternating Direction Implicit method and equivalent specific heat method are applied to establish a new high order mathematical model of3D temperature field, which could largely improve arithmetic speed and numerical precision.(3) The fuzzy mathematical theory is introduced, and the degree of similarity between the simulation results and experimental results is analyzed quantitatively by the Hamming Distance for the first time. This method is more scientific than the figure analysis.(4) A new FDM/FEM model has been developed to simulate the temperature field during the solidification process of squeeze casting. Squeeze casting experiments of magnesium alloy are incited for validating the new FDM/FEM model. It is shown that the results of numerical simulation are in agreement with the experimental results. Through this model, the influence of pressure on thermal physical parameters is considered, and the problem of getting the finite element meshes is resolved.(5) In this paper, a new FDM/FEM model has been developed to simulate the shrinkage defect. Squeeze casting experiments of aluminum alloy are incited for validating the new FDM/FEM model. It is shown that the results of numerical simulation are in good agreement with the experimental results. This FDM/FEM model is also suitable to the shrinkage defect prediction of magnesium alloy. (6) VTK is an object-oriented visualized class library. It has extensive capability in visualization and graphic processing. In this paper, the hierarchy and display way about VTK is introduced, and VTK is used in casting simulation software. Compared to other similar softwares that display results using OpenGL, the casting simulation software using VTK can display results of simulation more realistic.