For the sake of a more accurate shell boundary and calculation of radiation heat transfer in the Directional Solidification(DS) process, a radiation heat transfer model based on the Finite Element Method(FEM)is develo...For the sake of a more accurate shell boundary and calculation of radiation heat transfer in the Directional Solidification(DS) process, a radiation heat transfer model based on the Finite Element Method(FEM)is developed in this study. Key technologies, such as distinguishing boundaries automatically, local matrix and lumped heat capacity matrix, are also stated. In order to analyze the effect of withdrawing rate on DS process,the solidification processes of a complex superalloy turbine blade in the High Rate Solidification(HRS) process with different withdrawing rates are simulated; and by comparing the simulation results, it is found that the most suitable withdrawing rate is determined to be 5.0 mm·min^(-1). Finally, the accuracy and reliability of the radiation heat transfer model are verified, because of the accordance of simulation results with practical process.展开更多
The FEM analysis of stress and deformation of steel base of the special diamond saw blades are carried out.The small carbide round segments are welded on the side of blades in order to increase the side wear re sistan...The FEM analysis of stress and deformation of steel base of the special diamond saw blades are carried out.The small carbide round segments are welded on the side of blades in order to increase the side wear re sistance of blade.Comparing with conventional saw blade,the maximum stress val ues of reasonable special saw blade are reduced respectively about 17%20% 33%,and the maximum deformation values are reduced respectively about 26%22 %44.7%in thetangential(X),radial(Y)and axial(Z)direction.The stress conce ntration zone is decreased for the special structure diamond saw blade.The stru ctures of diamond saw blade with different number of hard material pellet are an alyzed and optimized.展开更多
In the process of milling the half-open impeller, the milling force ACTS on the half-open impeller will cause the machining deformation error of the half-open impeller. The impeller material studied in this paper is 7...In the process of milling the half-open impeller, the milling force ACTS on the half-open impeller will cause the machining deformation error of the half-open impeller. The impeller material studied in this paper is 7050-t7451 aluminum alloy, whose elastic modulus is 70.3 GPa, with low stiffness. Therefore, during milling, it is easy to cause elastic deformation of the cutter, thus causing machining errors and reducing machining surface quality. In addition, due to the low stiffness of blade surface, the deformation of blade surface is much larger than that of hub surface. Therefore, this paper only studies the deformation law of blade surface in the process of milling.展开更多
基金financially supported by the Program for New Century Excellent Talents in University(No.NCET-13-0229,NCET-09-0396)the National Science & Technology Key Projects of Numerical Control(No.2012ZX04010-031,2012ZX0412-011)the National High Technology Research and Development Program("863"Program)of China(No.2013031003)
文摘For the sake of a more accurate shell boundary and calculation of radiation heat transfer in the Directional Solidification(DS) process, a radiation heat transfer model based on the Finite Element Method(FEM)is developed in this study. Key technologies, such as distinguishing boundaries automatically, local matrix and lumped heat capacity matrix, are also stated. In order to analyze the effect of withdrawing rate on DS process,the solidification processes of a complex superalloy turbine blade in the High Rate Solidification(HRS) process with different withdrawing rates are simulated; and by comparing the simulation results, it is found that the most suitable withdrawing rate is determined to be 5.0 mm·min^(-1). Finally, the accuracy and reliability of the radiation heat transfer model are verified, because of the accordance of simulation results with practical process.
文摘The FEM analysis of stress and deformation of steel base of the special diamond saw blades are carried out.The small carbide round segments are welded on the side of blades in order to increase the side wear re sistance of blade.Comparing with conventional saw blade,the maximum stress val ues of reasonable special saw blade are reduced respectively about 17%20% 33%,and the maximum deformation values are reduced respectively about 26%22 %44.7%in thetangential(X),radial(Y)and axial(Z)direction.The stress conce ntration zone is decreased for the special structure diamond saw blade.The stru ctures of diamond saw blade with different number of hard material pellet are an alyzed and optimized.
文摘In the process of milling the half-open impeller, the milling force ACTS on the half-open impeller will cause the machining deformation error of the half-open impeller. The impeller material studied in this paper is 7050-t7451 aluminum alloy, whose elastic modulus is 70.3 GPa, with low stiffness. Therefore, during milling, it is easy to cause elastic deformation of the cutter, thus causing machining errors and reducing machining surface quality. In addition, due to the low stiffness of blade surface, the deformation of blade surface is much larger than that of hub surface. Therefore, this paper only studies the deformation law of blade surface in the process of milling.
