薄板多点成形中的拉裂现象研究

拉裂现象在薄板成形过程中很容易发生。文章采用有限元数值模拟手段,研究了薄板多点成形过程中的拉裂现象,分析了有压边多点成形时鞍形件的拉裂情况,提出了能够避免拉裂的柔性压边成形方式,分析了刚性压边与柔性压边成形时的成形极限与成形效果等,证明了柔性压边成形能够很好地解决板料起皱与拉裂的矛盾关系。当采用刚性压边多点成形时,加大压边力板料可能拉裂,减小压边力板料可能起皱;而采用柔性压边多点成形方式可以有效避免起皱和拉裂的发生,并且大大提高变形量,得到更好的成形结果。

Study on crack of sheet metal in the multi-point forming

Crack is a common phenomenon in multi-point forming(MPF).FEA Numerical simulation is used in this paper to simulate and study sheet metal crack in the deformation of MPF,and the crack of saddle workpiece with blank holder forming was analyzed in MPF.Furthermore flexible blank holder forming mode has been brought forward to avoid crack by improving processes,and forming limit and forming effect are analyzed by rigid blank holder forming and flexible blank holder forming.The contradiction of wrinkle and crack can be well settled by flexible blank holder forming.Results indicate that the sheet metal with rigid blank holder forming crack when blank holder force(BHF) is big,and sheet metal wrinkle when BHF is small.Otherwise wrinkle and crack have been avoided by flexible blank holder forming,and deformation can be increased greatly,and forming results is well.