摘要
The local and global mechanical responses of gas tungsten arc welds（GTAW） of a 2219-T87 aluminum alloy were investigated with experiment and numerical simulation.Digital image correlation（DIC） was used to access the local strain fields in transversely loaded welds and to determine the local stress-strain curves of various regions in the joint.The results show that the DIC method is efficient to acquire the local stress-strain curves but the curves of harder regions are incomplete because the stress and strain ranges are limited by the weakest region.With appropriate extrapolation,the complete local stress-strain curves were acquired and proved to be effective to predict the tensile behavior of the welded joint.During the tensile process,the fracture initiates from the weld toes owing to their plastic strain concentrations and then propagates along the fusion line,finally propagates into the partially melted zone（PMZ）.
通过实验和数值模拟方法研究2219-T87铝合金钨极氩弧焊接接头(GTAW)的局部及全局力学性能。采用数字图像相关(DIC)技术对拉伸过程的变形进行测量,并获取接头不同区域的局部应力-应变曲线。结果表明:DIC方法可以有效地测量非均匀接头的局部本构关系,但存在局限性,只有最薄弱区(断裂位置)才能得到完整的应力-应变曲线。通过外延得到了其他区域完整的应力-应变关系,并应用于单向拉伸模拟,模拟结果与实验结果具有良好的一致性,验证了材料本构关系的正确性。在拉伸过程中由于应变集中,裂纹从焊趾启裂,沿着熔合线扩展,最后扩展进入部分熔化区(PMZ)。
基金
Project(2012 2X04012-011)supported by the Innovation Platform for Process Modeling and Simulation of Advanced Materials Processing Technologies,China
