环形筋压筋不起外皱的临界计算及试验研究

拉深筋可以用来防止内皱的出现。本文对拉深件成形前环形筋在压靠过程中，筋的外围材料不发生外皱的机理进行了理论分析和试验研究，得到了压筋时不起外皱的临界表达式。为了得到环形筋的合理位置，本文还推出了材料在压筋时不被拖入艋中的验证公式。

EXPERIMENTAL STUDY AND CRITICAL CONDITION COMPUTING FOR PREVENTING OUTER WRINKLING IN THE USE OF DRAW BEAD

A round draw bead can prevent the forming of inner wrinkling.Before the drawn piece is formed,the material outside the draw bead will undergo complex changes.All these changes will affect the forming process of outer wrinkling,in other words,they will decide whether outer wrinkling will be brought about or not.This situation is analyzed theoretically and tested by experiment.Finally,a critical condition expression is given which shows the way to prevent outer wrinkling in the use of the round draw bead,and an experience formula is derived which tells the best location of the draw bead.