非平底凹模复合成型中板料成型有限元分析

来源期刊：中南大学学报(自然科学版)2002年第3期

论文作者：陈明安 张新明

文章页码：274 - 277

关键词：金属板料成型;塑料注射成型;有限元;金属/塑料宏观复合材料

Key words：sheet metal forming; plastic injection molding; finite element method; metal/plastic composite

摘    要：金属板料与塑料复合成型中采用非平底凹模结构制造复杂轮廓形状的复合零件时,金属板料的轮廓形状受到金属板料成型极限的限制.作者用复合成型试验和弹塑性大变形有限元方法揭示了表面轮廓形状较复杂的结构零件复合成型中金属板料的成型过程.变形板料划分为6个区域:凸缘区(Ⅰ区)、模腔入口圆角区(Ⅱ区)、与模底接触区1(Ⅲ区)、模底圆角过渡区(Ⅳ区)、与模底接触区2(Ⅴ区)及Ⅱ区与Ⅴ区之间的自由变形区(Ⅵ区).研究结果表明:Ⅰ区与Ⅱ区处于拉伸变形状态,Ⅲ区处于板面内双向伸长变形状态;由于模具轮廓形状的急剧变化以及小圆角半径的影响,Ⅳ区内剪切和弯曲作用强,并形成一个板厚大大减薄的大塑性变形区;当熔体压力超过28 MPa时,板料的变形主要集中在Ⅵ区,并在Ⅵ区与Ⅱ区和Ⅵ区与Ⅴ区交界处形成2个板厚减薄较严重的大塑性变形区.

Abstract: In hybrid forming of complex macro-components combined of sheet metals and plastic with the mold of non-flat bottom, the shape of the formed sheet metal is limited by the formability of the sheet metal. The updated elastic-plastic Lagrange finite element formulation and the hybrid forming experiment have been used to analyze the forming process of the sheet metal in the hybrid forming process. It is shown thatthe formed sheet part can be divided into sixregions, i.e. the flange region (regionⅠ), the mold entry region (regionⅡ), the contact region with bottom 1 of the mold (region Ⅲ), the contour change region of the mold (regionⅣ), the contact regionwith bottom2 of the mold (regionⅤ), and the free forming region betweenⅡandⅤ(regionⅥ). RegionsⅠandⅡare in deformation of deep drawing, and region Ⅲin stretch forming in plane of the sheet. Ahighly strained zone with the severest thickness reduction is developed in regionⅣdue to deformation of shear and bending caused by sharp change of the mold contour and the small radius,the further deformation is concentrated in regionⅥ, and a highly strained zone second to regionⅣis formed between regionⅡand regionⅥand a third highly strained region is developed between region V and regionⅥwhen the plastic melt pressure exceeds 28 MPa.