模具圆角半径对多向压缩变形的影响及模具改进

Influence of die fillet radius on multi-axial compression and die improvement

通过对多向压缩变形过程的有限元模拟,获得了不同圆角半径多向压缩的等效应变分布,分析了圆角半径对变形程度、变形均匀性的影响。结果表明:多向压缩变形后的试样在圆角处形成了高应变的棱边变形带,棱边交汇的角部区域应变更高,且角部容易产生纵向毛刺,圆角越大这种现象越加明显。棱边变形带中间部位等效应变比较低,两端很高,这两处的差值随圆角半径增大而增加,当圆角半径达到4mm时,端部等效应变达到中部的两倍多。变形后试样中间截面高应变区呈现X状分布,中心应变最高,中间截面的平均等效应变和变形均匀性随圆角半径增加均有所下降。因此,多向压缩模具型腔不宜带有圆角。对多向压缩模具进行了改进,去除了型腔圆角,并可延长模具寿命。

The equivalent strain distribution of multi-axial compression（MAC）with different fillet radius was obtained based on the finite element simulation and the influence of fillet radius on deformation degree and deformation uniformity was analyzed.The results showed that a high strain edge deformation zone at the fillet of the specimen was formed after MAC,the equivalent strain in the corner area with edge intersection was higher,and the corners were prone to produce longitudinal burrs.The bigger the fillet was,the more obvious the phenomenon was.The equivalent strain in the middle part of the edge deformation band was relatively low and the two ends were very high.The difference between the two areas above increased with the increase of fillet radius.When the fillet radius was 4 mm,the equivalent strain of the ends was two times more than that of the middle part.The distributions of high strain area in the middle section was like a X after deformation,the central strain was the highest,and both the mean equivalent strain and deformation uniformity of the middle section decreases with the increase of fillet radius.Therefore,the MAC die cavity should not have die fillet.In this paper,the MAC die has been improved to remove the die fillet and prolong the die life.