CAJ | 학술논문

针对传统FLC无法准确预测超高强度双相钢薄板在较小凸模圆角下拉弯成形时的剪切开裂问题，采用基于延性准则的成形判据计算其应力‐应变失效积分因子，结果表明，使用Brozzo 和Oyane延性准则计算的失效积分因子在凸模圆角处超过失效单位值，与试验相符，说明Brozzo、Oyan延性准则能够实现小圆角半径下双相钢板材在拉弯成形中的开裂预测。
침대전통FLC무법준학예측초고강도쌍상강박판재교소철모원각하랍만성형시적전절개렬문제，채용기우연성준칙적성형판거계산기응력‐응변실효적분인자，결과표명，사용Brozzo 화Oyane연성준칙계산적실효적분인자재철모원각처초과실효단위치，여시험상부，설명Brozzo、Oyan연성준칙능구실현소원각반경하쌍상강판재재랍만성형중적개렬예측。
Since the conventional forming limit criterion (FLC) cannot be used to accurately predict the shear fracture of super strength dual phase (DP) steel sheet in stretch bending with small punch radius ,the ductile criteria were used in this study to cal‐culate the stress‐strain failure integral for key elements under stretch bending limit .The results show that the integral factor cal‐culated by Brozzo or Oyane criterion exceedsthe unit value for the elements around the punch radius ,which indicates fracture fail‐ure at such area and agrees well with the experiment .It can be concluded that ductile criteria proposed by Brozzo and Oyane can be used to predict the shear fracture occurred in the stretch bending of DP sheets under small punch radius .