7075-T6复杂加载状态下断裂极限研究
为研究航空铝合金AA7075-T6板材在复杂加载状态下的韧性断裂力学性能,设计4种包含不同应力状态的拉伸试验和液压胀形试验来获取材料的硬化特性和断裂参数。通过不同应变率和不同轧制方向的拉伸试验得到相应的应力-应变曲线,分别采用不同硬化模型和DF2016韧性断裂准则对其硬化行为和断裂特性进行表征。结果表明AA7075-T6狗棒试件在应变率为1 s-'和 10 s-时重复性较好,应变率为100 s‘时应力-应变曲线出现明显的抖动,但随着应变率的增加没有出现明显的应变率强化效应。而且对比7个轧制方向的应力-应变结果发现,不同角度的拉伸强度和断裂应变基本相同。因此在研究范围内AA7075-T6表现为一种各向同性且关于应变率不敏感的材料。采用Swift-Voce硬化模型的预测效果最好,DF2016韧性断裂准则可以准确预测AA7075-T6在剪切、单轴拉伸、平面应变拉伸和等轴拉伸等不同应力状态的断裂位置。
In order to study the ductile fracture mechanical properties of aviation aluminum alloy AA7075-T6 sheet under complex loading states , four tensile tests and hydraulic bulging tests with different stressstates were designed to obtain the hardening properties and fracture parameters of the material. Corre-sponding stress-strain curves were obtained through tensile tests at different strain rates and rolling direc-tions , and different hardening models and DF2016 ductile fracture criterion were used to characterize theirhardening behavior and fracture properties. The results show that the AA7075-T6 dogbone specimen hasgood repeatability when the strain rate is 1 s-' and 10 s -',and the stress-strain curve shows obvious jitterwhen the strain rate is 100 s -',but it does not increase with the increase of the strain rate.A significantstrain rate strengthening effect appears.Moreover , comparison of the stress-strain results in the seven roll-ing directions reveals that the tensile strength and fracture strain of different angles are basically the same.Therefore AA7075-T6 behaves as an isotropic and insensitive material with respect to strain rate in the study range. The Swift-Voce hardening model is used to predict the best results , and the DF2016 ductilefracture criterion can accurately predict the fracture position of AA7075-T6 in different stress states suchas shear , uniaxial tension, plane strain tension and equiaxed tension.
江娜、娄燕山、张冲、尚宏春、李旭阳、王松臣、王计真
航空有色金属冶炼金属压力加工
断裂参数7075铝合金应变率力学性能试验
江娜,娄燕山,张冲,尚宏春,李旭阳,王松臣,王计真.7075-T6复杂加载状态下断裂极限研究[EB/OL].(2023-03-20)[2025-08-23].https://chinaxiv.org/abs/202303.00394.点此复制
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