CAJ | 학술논문

成形极限曲线可展现板料在塑性失稳前所能达到的最大变形程度，是板料成形分析中的重要判据。为获得准确的试验成形极限曲线，该文通过刚性半球凸模胀形试验、采用数字散斑图像相关方法对AA6061铝板的成形极限曲线进行测定，得出了成形极限试验测定和极限应变提取的方法；通过对A A6061铝板进行盒形件拉深试验，建立拉深过程的有限元模型，比较了数值模拟和试验测定的极限拉深深度。比较结果表明，数字图像相关方法能够有效获取变形过程中的全场应变信息、搜索临界破裂状态，且能采用曲线拟合方式计算极限应变，避免了人为误差，提高了测量精度。拉深试验表明，所测成形极限曲线对拉深极限具有较高的预测精度。
성형겁한곡선가전현판료재소성실은전소능체도적최대변형정도，시판료성형분석중적중요판거。위획득준학적시험성형겁한곡선，해문통과강성반구철모창형시험、채용수자산반도상상관방법대AA6061려판적성형겁한곡선진행측정，득출료성형겁한시험측정화겁한응변제취적방법；통과대A A6061려판진행합형건랍심시험，건립랍심과정적유한원모형，비교료수치모의화시험측정적겁한랍심심도。비교결과표명，수자도상상관방법능구유효획취변형과정중적전장응변신식、수색림계파렬상태，차능채용곡선의합방식계산겁한응변，피면료인위오차，제고료측량정도。랍심시험표명，소측성형겁한곡선대랍심겁한구유교고적예측정도。
Forming limit curve is used to describe the formability of metallic sheet before plastic instability ,which is an important material property .Rigid hemisphere punch bulging test for AA6061 aluminum alloy was performed with a three dimensional digit‐al speckle correlation strain measuring system ,a method of performing forming limit experiment and processing limit strain is giv‐en .Also ,the experiments and numerical simulation of box part deep drawing for AA6061 were performed ,then the limit drawing heights of them were compared .The results show that :the digital speckle correlation is able to capture the whole strain field . The suggested method could better search the critical fracture condition ,and the curve fitting method is used to capture the limit strain ,which improves the measuring accuracy without artificial selection of critical point .The verification of deep drawing test shows that the obtained forming limit curves can give a higher prediction accuracy for drawing fracture .