A Study On Software Used For Numerical Simulation On Solidification Process Of Ductile Iron Castings

In this thesis, a set of software was developed used for numerical simulation on solidification process of ductile iron castings. The software was made of three parts: the program of pre-processing used for auto-mesh generation, the simulation calculating program of ductile iron and the program of post-processing used for displaying simulation result. The software was developed with Visual C++ programming language and used object oriented programming technique based on PC windows system. The software was characterized by comprehensive functions, high display speed and easy manipulating.The pre-processing program took the advantage of graphic data interface STL file which generated from medium or top-grade CAD software, base on STL solid model the auto-mesh generation codes used for numerical simulation of casting solidification process were developed. The principle of the auto-mesh generation is: first of all, using STL solid model's continuity to speed up the process of model's cutting, and the contour lines of each layer were calculated. Secondly, on the cutting planes, according to area filling algorithm, the cells enveloped by contour lines were determined and given an according material number. For the casting-model system of various kind of material, according to this method, the STL solid models were treated one by one to carry out the mesh generation with predetermined order and material property. In order to meet the need of observing differ material STL solid models and it's location relations, the OpenGL technology has been adopted and realized the 3-dimensional solid model's display.In the simulation calculating program, a quite simple measure to store andThe research is supported by school youth scientific fundcall the coefficients in discrete equations was adopted, for the system unequally divided in three dimensional spaces, the measure made the CPU time for computing temperature field greatly reduced. The latent heat release process was perfectly simulated by using an exponential relationship between solid fraction and temperature.In the post-processing program, taking the advantage of windows GDI technology, the program can display casting's 3-dimensional meshed graph, the casting solidification processing animation and the distribution of 3-dimensional temperature field. The program also includes general 3-dimensional graphic function such as cutting, rotation and zooms as to make the simulation resulting visualizing.The software has been applied to middle complex castings in real manufacture, the result indicated the software is reliable, effective and has certain practicable value.