Research On Drawing Forming Force And Energy Parameters Of Complex Die Surface

Complex die surface drawing can reduce drawing force,improve the surface quality of products and reduce the loss of the die,which is of great significance to the development of economic society that emphasizes resource conservation.Drawing force is the basis for accurately regulating the drawing process of complex die surface.It mainly has two kinds of theoretical analysis methods.One is simulation method and the other is analytical method.The former can give discrete numerical results for complex problems,but it is difficult to adapt to the changes of various production conditions due to its poor universality.The latter is favored for its clear physical meaning and rigorous mathematical expression.However,a new analytical method must be found to solve the problem that difficulty in solving non-linear mechanical equations when dealing with complex die surface drawing.In order to solve this problem,this paper studies the design of complex die surface and the analysis of corresponding force and energy parameters.The main research contents are as follows:(1)A twin elliptical drawing die that meets the requirements of stream function is designed to solve the problem of wire drawing,and analyzing the plastic forming mechanics during die drawing.The kinematically admissible velocity field and strain rate field that meets the requirements of stream function has been established on basis of satisfying the velocity boundary conditions.The mathematical expressions of internal plastic deformation power and friction power in drawing are obtained by using the mean value theorem of integral,as well as the effects of friction factor and reduction ratio on the optimal die semi-angle.(2)The non-linear Mises Yield Criterion which make it very difficult to get the integral solution of the metal plastic deformation power.Therefore,a linear yield criterion is proposed,and the expression of its plastic power and its corresponding comparative verification are also given.(3)A method of calculating the internal plastic deformation power of tube sinking drawing by using specific plastic power is proposed.The maximum reduction rate and the optimal die semi-angle are obtained by minimizing the total power and the relative drawing stress state coefficient.The finite element simulation technology was used to analyze tube sinking drawing,and obtaining the influential law of the change of die geometric parameters.(4)The finite element simulation of cubic surface drawing is carried out,the BP neural network prediction model is trained with the obtained simulation data,and the BP neural network prediction model of cubic surface drawing force has been established.This model reflects the effect of die semi-angle,friction factor and reduction rate on drawing force.