剪切夹具设计及铝合金循环剪切变形行为

目的 研究金属薄板在剪切变形条件下的随动硬化行为。方法 设计一款金属薄板循环剪切变形试验夹具，对夹具的强度进行数值仿真校核。采用该夹具进行5052铝合金板的循环剪切试验，通过数字图像相关测量系统对剪切应变进行跟踪测量，对变形区剪切变形的均匀性进行分析，对5052铝合金的循环剪切应力应变曲线所表现出的包辛格效应进行讨论。结果 该夹具满足强度要求，剪切变形区的剪切应变与等效应变比值非常稳定，5052铝合金板的正向剪切强度与反向剪切强度不同，在3.97%和7.1%剪切应变时，包辛格效应系数分别为0.328和0.51。结论 所设计的夹具可以有效实现剪切变形，剪切应变分布均匀；试验所用的5052铝合金具有显著的包辛格效应。

Design of Shear Fixture and Cyclic Shear Deformation Behavior of Aluminum Alloys

In order to investigate the kinematic hardening behavior of metal sheets subject to shear deformation, a set of shear fixture was designed to provide cyclic shear deformation for metal sheets. Strength of the fixture was checked with finite element simulation. Cyclic shear deformation experiments of 5052 aluminum alloys were performed with a newly designed fixture. The shear strain in the shear deformation zone was monitored with the digital image correlation measurement system. The uniformity of the shear strain distribution in the deformation zone was analyzed. Bauschinger effect shown in the cyclic shear stress-strain curves of the 5052 aluminum alloy was discussed. The fixture met the requirement on strength. The ratio of the shear strain with the effective strain was almost constant in the deformation zone. The yield strength of AA5052 under forward shear was different with that under the reverse shear. The Bauschinger effect factor was 0.328 and 0.51 when the shear strain was 3.97% and 7.1%, respectively. The new fixture can provide a perfect shear deformation condition and the shear deformation is evenly distributed. The investigated 5052 aluminum alloy has remarkable Bauschinger effect.