Research On Deep Drawing Of Cylindrical Parts Considering Anisotropy

The anisotropy of the sheet metal due to rolling is the main reason for the ear caused by the deep drawing of the cylindrical part.The ear is an obvious product defect that needs to be removed by a trimming process.The traditional drawing process of cylindrical parts takes isotropy as the basic assumption and ignores the existence of ear defect.In this paper,for the SPCC sheet,a combination of theoretical analysis,FEM simulation and experimental research is used to carry out the research on the drawing of cylindrical parts considering anisotropy.The formula for calculating the height of the cylindrical parts is derived.The influence of sheet anisotropy and process parameters on ear formation and wall thickness change are analyzed and clarified.The main research contents and conclusions are as follows:(1)Theoretical analysis of drawing cylindrical parts with anisotropic.Through theoretical analysis of the stress,strain and deformation of the flange area in the drawing of the cylindrical part,the calculation formula of the height of the cylindrical part is established on the basis of considering anisotropy.By calculating the height of the cylindrical member under different plastic strain ratios,the earing rate of the cylindrical member is obtained,and it is found that the plastic strain ratio has an important effect on the earing rate.(2)FEM simulation of drawing cylindrical parts with anisotropic.A unidirectional tensile test was performed on a SPCC sheet with a thickness of 0.77 mm,and the plastic strain ratios and other main mechanical parameters in the directions of 0 °,45 °,and 90 ° were obtained.A simulation model for deep drawing of cylindrical parts with an outer diameter of? 50 mm considering the anisotropy was established,and the distribution and variation of equivalent stress,equivalent strain,forming limit and wall thickness reduction of the cylindrical parts during drawing.The simulation results show that the cylindrical part has obvious ear phenomenon,and the height of the cylindrical part and the wall thickness of the ear part are closely related to the plastic strain ratio.(3)Experimental study of drawing cylindrical parts with anisotropic.An experimental platform was constructed with the electromagnetic blank holder deep drawing experimentaldevice as the main body,and the experimental research on the deep drawing of the cylindrical member was carried out.The cylindrical parts with an outer diameter of ?50mm were obtained through experiments.The influence of the sheet diameter and blank holding force on the distribution of the ears and wall thickness reduction of the cylindrical parts was obtained.Found that the larger the diameter of the sheet,the more obvious the ear phenomenon,the thicker the thickness of the ear,and the smaller the effect of the blank holding force on the ear.By comparison the height of the ears obtained from the experimental samples with the theoretical calculation formula,it is found that the two agree well,which verifies the accuracy of the theoretical calculation formula.By comparison the experimental samples with the simulation results,the agreement between the contour of the cylindrical part and the thickness curve of the cylinder wall is good,which verifies the accuracy of the simulation model and results.This simulation model lays the foundation for subsequent research.(4)Influence of process and anisotropy parameters on deep drawing of cylindrical parts.Based on the above-mentioned cylindrical part drawing FEM simulation model and method,through orthogonal experiments,the main process factors that affect the cylindrical part drawing lug behavior are as follows: drawing ratio,sheet thickness,static friction coefficient and blank holder force.The effects of process and anisotropic parameters on ear behavior and wall thickness reduction rate were analyzed through simulation.Found that the drawing ratio increases,the earing rate increases,and the wall thickness reduction rate of the ear part decreases;when the sheet thickness increases,the earing rate increases,the wall thickness reduction rate of the ear part decreases,the thickness reduction rate of the wall of the rounded part of the punch increases;when the blank holding force increases,the earing rate decreases,the blank holding force is small,the thickness of the ear is small,and the wall thickness reduction rate of the rounded part of the punch increases;when the plane anisotropy coefficient increases,the earing rate increases,and the wall thickness reduction rate of the rounded part of the punch increases;the strain hardening index increases,the earing rate decreases,and the wall thickness reduction rate of the rounded part of the punch increases.The above research results are helpful for understanding the influence of sheet anisotropy on the drawing of cylindrical parts,and can provide a basis for optimizing thedrawing process of cylindrical parts,setting reasonable process parameters,and improving product quality.