| During the casting process of Aluminum cylinder head, crack defect is often appeared. To solve the problem, entity model of cylinder head is established using the ANSYS software. Then the casting solidification process is simulated based on thermal theory and elastic-plastic theory. At last, optimization of the solidification process is conducted according to the result of simulation.According to the thermal-delivering theory and elastic-plastic theory, the temperature and internal energy of the system are significantly variant during the casting solidification process. Considering the latent heat of solidification, the thermal analysis about casting solidification process of the aluminum cylinder head is non-linear and transient. The casting stress is generated during the process. When the residual stress exceeds the yield stress, the bull crack is easily generated.The bulge and some holes which have little influence to the structure are predigested. According to casting technology diagram, the 3-D models of the cylinder head and the sand mould are established. Parts of the model are connected through Boolean operation.FEM(Finite Element Method)mesh is set up, using the SOLID70 element of ANSYS. The loads of air conduction and radiation are ignored. Taking the air convection, sand conduction, and the latent heat into consideration, the nonlinear-transient thermal analysis is solved. And the distribution of temperature field during the solidification process is obtained.The result of thermal analysis is set as the body loads. Using the SOLID45 element, the thermal stress analysis is solved. The distribution of stress field is obtained.Optimization of the solidification process is also done with ANSYS. The time of sand-removing and the convection coefficient are set as design variables. The thermal-stress is set as object function. The result shows that the generation of defect would be avoided if the time of sand-removing were postponed and the convection coefficient was increased.
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