Numerical Simulation Method For Electric-thermal Multi—physics Coupling Based On Numerical Manifold

Multi-physics coupling process is a complex physical process, in this process, electricity and heat impact simultaneously, material dramatic changes in temperature, and attribute is extremely uniformity. Two physical fields of electricity and heat have the strong interactions. In the coupling deformation process, material of resistivity, coefficient of thermal conductivity and conductive heat conduction performance along with the work temperature which affect the properties of materials and the distribution of the electric field and temperature field. Different nature of the physical parameters such as electricity and heat influence each other. Some parameters can directly control and test, but other parameters can not control directly. In actual production, electric thermos multi-physical coupling deformation processes are widely existence, and electrical upsetting is a kind of typical electric thermos multi-physical coupling deformation process. Therefore, researching on the mechanism of electric thermos multi-physical coupling deformation process of the interaction has important significance to guide the practical production process.This paper is based on the National Natural Science Foundation of China granted project,"multi-physical coupling large deformation mechanism research of electric upsetting process". This paper uses the manifold method to deduce electric thermos multi-physical coupling numerical manifold format, establish the coupling mechanism of electric thermos based on numerical manifold. Simulate the multi-physical coupling process of the electric upsetting process in preheating stage and reveal the electric field and temperature field distribution reguarity for multi-physical coupling of the electric upsetting process in preheating stage. The main contents are as follows:1. Using the manifold method to derive the electric field format, establishing the electric field simulation numerical manifold method, and writing the electric field numerical simulation program based on the numerical manifold method. Using the program to analysis electric field distribution of the electric upsetting forging process of forming preheat stage. Different grid number and different coverage on potential distribution function were used to simulate, and comparing the result with the finite element analysis software Marc. The results shows that:in the manifold method, using the same cover function, the calculation precision increased along with the increase of the number of grid;and using the same number of grid manifold unit, the calculation precision increased with the increase of the number of the cover function; Using less number of grid can get the same calculation precision with the finite element method.2. Using the manifold method to derive the temperature field format, establishing the temperature field simulation numerical manifold method, and writing the temperature field numerical simulation program based on the numerical manifold method. Using the program to analysis temperature field distribution of the electric upsetting forging process of forming preheat stage. Different grid number and different coverage on potential distribution function were used to simulate, and comparing the result with the finite element analysis software Marc. The results shows that:in the manifold method, using the same cover function, the calculation precision increased along with the increase of the number of grid; and using the same number of grid manifold unit, the calculation precision increased with the increase of the number of the cover function; Using less number of grid can get the same calculation precision with the finite element method.3. Establishing the manifold method format of the electric thermal coupling, and writing the electric thermal coupling numerical simulation program based on the numerical manifold method. The program were used to simulate the electric thermal of the process of preheating process of electric upsetting, and getting the electric field and temperature field distribution of the process. The results show that:in electric upsetting forming preheating stage, material internal potential is not equally distributed. Contour is equality and asperse near the surface, and contour is dense and bending shape near the electrode. The highest temperature of the material is near the surface. The contour is dense near the surface and sparse in the middle and top of the material surface.