The Analytical Analysis And Numerical Simulation Of The Coating Sheet’s Forming Process

At present stamping technology about metal sheet has mature, but the researchabout composite sheet forming needs a lot of work to do, especially to the coatingsheet has special function. Coating sheet have more complex forming process thansingle sheet, deformation is harder to predict. Introducing numerical simulationtechnology can effectively reduce the number of research and savings cost.After consulted a large number of literature, I have a deep understanding aboutthe current status of the coating sheet stamping, and found a suitable method toresearch coating sheet forming limit, studied the electrodeposited nickel coatingforming limit’s left region using the method. The results of the study indicate thatequivalent strain curves of the coating and substrate are very close, when thickanisotropic indices of substrate are different, the equivalent strains are different onthe same strain path. And the results also show that the thickness of coating have alittle influence to the forming limit.Finally we do a simulation analysis about multi-channel punching process usingprofessional finite element analysis software. The result of the simulation as follows:First,the maximum equivalent stresses and strains of the substrate and coatinghave occurred on the concave die round. Stress distributions of the substrate andcoating have the same trend, but the coating under the substrate and the coating on thesubstrate have some different with the substrate. The equivalent strains of coating andsubstrate are very similar on the same node. The sixth and fifth stamping have thesame situation, their stresses and strains are in the same order of magnitude.Second，when the fifth stamping is over,the thickness of the cup bottom is only0.268mm, the thickness on the flange top is0.294mm. Compared with the sheetthickness of the initial，the thinning rate is7.5%and thickening rate is8.9%. Whenthe sixth stamping is over,the thickness of the cup bottom is only0.268mm, thethickness on the flange top is0.314mm. Compared with the sheet thickness of theinitial，the thinning rate is7.4%and thickening rate is16.3%. Compared with thesheet thickness of the fifth stamping，the thinning rate is0%and thickening rate is6.8%, this shows that,the deformation of sheet metal is very small at thecircumferential direction.The last, maximum punch pressures produced by two stamping process are different, the punch pressure produced by the sixth stamping is bigger than the fifth,This shows that smaller diameter size need bigger punch pressure to finish thestamping process.