圆盘剪分切断面形貌形成机理研究

Formation Mechanism of Disc Slitting Surface Morphology

为深入分析圆盘剪分切加工机理和提高分切质量,应用DEFoRM-2D仿真软件研究圆盘剪分切过程中镀锌板断面形貌特征及形成机理,仿真与试验结果具有较好的一致性。断面形貌特征的形成与分切过程中板材的应力应变状况密切相关,利用板面历史最大切应力变化可以预测塌角和挤压带宽度的变化趋势,根据塌角开始和终止成形时刀具行程差可以判断塌角高度变化趋势。随着离圆盘刀侧边距离的增大,塌角区板面的历史最大切应力先增大后减小,而挤压带板面切应力逐渐减小。随着圆盘刀的切入,板材的剪切力先急剧增大,然后缓慢增大到峰值后缓慢下降,出现裂纹后迅速减小。圆盘刀之间的侧向间隙直接影响板材的应力应变、裂纹的形成及其扩展,从而决定板材的剪切力和分切断面形貌,较大的侧向间隙有助于裂纹的扩展。

To understand thoroughly the mechanisms of the disc slitting process and improve the slitting quality,the slitting surfacemorphology of galvanized steel sheet is numerically analyzed by using the DEFORM-2D finite element analysis software,and theformation mechanism of the slitting surface morphology is clarified.The numerical simulation results are in good agreement with theexperimental results.The formation of the morphology characteristics is closely related with the stress-strain distribution of the sheetmetal in the disc slitting process.The widths of the rollover and compressive area can be predicted by tracking the history of themaximum shear stress on the sheet surface,and the cutter travel between the beginning and ending of the forming of the rollover isproposed to estimate the change tendency of the rollover＇s height.With the increase of the distance from the edge of the disc cutter,the shear stress of the points on the rollover area increases at first and then decreases,while that on the compressive area decreasesgradually.When the disc cutter cuts into the sheet metal,the shear force increases rapidly at first,then ascends slowly to a peak,nextdecreases slowly,and reduces sharply after the cracks appear.The slitting clearance between the neighboring disc cutters determinesthe stress-strain distribution of the sheet metal and the occurring and propagating of the crack,thus influences the shear force and theslitting surface morphology.A large clearance can promote crack propagation.