Study On Finite Element Analysis Technique Of The 3d Temperature Field And Thermal-stress Field In Foundry Freezing Process

Finite element analysis (FEA) simulation of the temperature field and stress field in the foundry system freezing process greatly promotes the development of the foundry field, and plays an important role in the optimize technics designing, shrinkage,dispersed shrinkage,segregation analyzing , avoiding hot crack faults, decreasing residual stress, and improving the casting quality.In this thesis, first the development of the numerical simulation of the freezing process, and prospect the developing trend in the future are summarized. An elastic-plastic 3D FEA model of the transient temperature field and thermal-stress field is theoretically built. And a mathematical model of the initial condition, boundary condition, and latent heat disposal is built as well.Basing on the FEA softwareNSYS, the analytical procedure of the temperature field and thermal-stress field are exploited. Considering to the character that the material's performance changes along with temperature, nonlinear analysis in the procedure is adopted. An FEA analysis is finished for the stress frame 3D temperature field and thermal-stress field of the typical casting-stress frame. The result indicates that the numerical value simulation of 3D temperature field can basically reflect the dynamic change of the temperature field in the casting cooling process. And the result nicely tallies with the actual measurement, while the calculational outcome of residual stress is basically consistent with measured result.After the 3D FEA to the temperature field of the cylinder lid on diesel engine, which is more complicated and adopted in the practical producing, the temperature fields during the solidification and cooling process under different technical conditions are worked out, and the three kinds of shakeout technics schemes are appraised. It indicate that the time spent on shakeout influence the residual stress of the casting greatly, but it's inadequate just considering the shakeout temperature. Some other factors, such as material quality, structure etc should also be synthetically put into consideration. Thus it can also be seen that the 3D temperature field procedure mentioned in this article has certain practical significance. It can play an important role in improving the manufacture quality, reducing the waster rate and increasing the economic benefits.At last, the residual stress on cylinder lid, which is produced in the foundry process, was measured. The outcome indicates that enormous crushing stress exists on the lid.