Research On Finite Element Numerical Simulation Techniques Of3D Temperature Field In Process Of Casting Solidification

Computer technology has been the important tools of high quality parts, and it is thedevelopment direction of modernization advanced manufacturing. Finite elementtechniques is fast developing, and has become increasingly important in the optimizedesigning, forecasting casting defects, and improving the casting quality. Temperaturefield simulation has the important theoretical and practical significance in the field as thebasis research.Firstly, it was generalized that the present research situation of the simulationtechnology of the freezing process, and the development trend in the recent future. In thisthesis the heat transfer theory and the finite element method were used to build the3Dmathematical model of the transient temperature field. The weighed residual method ofGalerkin was used to develop the variation equation of3D transient temperature field. Thefinite element method combining with the finite difference method was used to discretethe time and space variables in the heat conduction equations in the process of castingsolidification so as to obtain the algebraic equations for temperature field calculations.It is discussed that the key technologies of casting solidification temperature field,including the basic principles to mesh tetrahedral element of the finite element method,element model of the calculation program, element matrix transformation and numericalintegration conversion rule to calculate the global coordinate system points, treatmentmethod of casting/mold internal contact boundary. The whole design idea and algorithmflowchart of reading/writing of the pre-processing grid files and the self-developedcalculation program were also introduced.As the application of3D temperature field numerical simulation, the calculation ofthe temperature distribution of a steel ball and an actual complex structure in the coolingprocess were emphatically introduced as examples. Compared with the results calculatedby analytical solution and ANSYS, the outcome matches well with them. The resultsverify the correctness algorithm of the calculation program as well as the reliabilityoutcome is verified by the simulation results.As the application of the temperature field of the freezing process, the method for processing the internal contact boundary element of common nodes and non-commonnodes was used. The calculation of the temperature distribution of an I-shape pieces andan actual complex wheel hub castings in the freezing process were introduced as examples.Compared with the results calculated by analytical solution and InteCAST, the correctnessof the program algorithm was verified. The error source of the calculation results was alsointroduced, and then the three-dimensional temperature distribution and variation withtime of the castings were presented.Finally, this paper gave a prospect of improving and perfecting thoughts andapproach for FEM simulation on3D temperature field in process of casting solidification.