Finite Element Simulation And Tolerance Analysis Of Zr Alloy Sheet Blanking Clearance

In recent years, facing the dual pressures of sustained growth in energy demand and greenhouse gas emissions, developing nuclear power safely and efficiently has become an important research direction for energy structure adjustment in our country. Zirconium alloy sheet is critical for operation of reactors efficiently and safely, as an important material of spacer grid structures in nuclear reactors. Mastering the blanking law of zirconium alloy sheet and achieving localization of the spacer grid completely has become one of the key technologies for the development of China’s nuclear power.Research on the zirconium alloy material is still in its infancy and the cost is very expensive, as to obtain a reasonable blanking gap through extensive tryout test according to the general method, the research cost of which is high, so the utilization of finite element simulation is more economical. However, the current research of punching by finite element simulation is mostly for common isotropic material, and the blanking law of zirconium alloy is more complicated for its obvious anisotropy. Therefore, the finite element simulation of zirconium alloy sheet metal punching gap and the tolerance analysis have important engineering value. The main researches in this paper are as follows:(1) A few basic parameters were obtained by tensile test of zirconium alloy sheet firstly. Then the finite element simulation was carried on to study the influence of different punching blanking gap on punching blanking force, punching power and section quality of punching items, and reasonable value of blanking gap was analyzed.(2) Considering the obvious anisotropy of zirconium alloy, the finite element simulation of blanking gap with different normal anisotropy coefficient was investigated, and the influence of reasonable value of blanking gap and anisotropy of sheet on section quality was analyzed when punching edge and sheet rolling direction showed the different angles.(3) The three-dimensional tolerance analysis of a standard four pillar sets blanking die was studied by Jacobian spinor statistical algorithm combined with assembly crafts of die, with closed loop of punch positioning tolerance, and the influence of punch positioning tolerance on blanking gap was researched.Based on the study of zirconium alloy sheet blanking clearance, the discoveries are: using finite element techniques combined with punching law to obtain reasonable blanking clearance is an effective method; anisotropy of zirconium alloy sheet material has no significant effect on the value of reasonable blanking clearance, but influence obviously on the quality of the workpiece section; the tolerance analysis of blanking die calculated by Jacobi spinor statistical algorithms shows that the punch positioning tolerance has significant influence on the blanking gap.