相较于传统材料性能测试试验，管材液压胀形实验能更准确的复现管材在流体面力作用下的材料流动及硬化规律。针对传统测量方法中存在的破裂冲击及轴向轮廓测量难等现象，利用三维数字图像相关法(3D-DIC)对5A02铝合金管材胀形试验进行测量。建立了管材自由区域的力学模型，给出了自由区域壁厚分布的计算方法，获取了5A02铝合金管材的本构方程，并采取有限元方法对上述结果进行对照验证。结果表明，采取幂指数形式的本构方程的最大相对误差小于10%，轮廓最大相对误差误差小于1.5%，壁厚最大相对误差小于2%。最后，通过控制自由区域的长径比获得了5A02管材左侧成形极限曲线(FLC)。

The constitutive equation and the forming limit diagram are effective means for evaluating the deformability and formability of the metal material. Compared with the traditional tube mechanical properties test, constitutive equa-tion and forming limit of the tube under the action of fluid force will get more accurate through the tube bulging test(TBT). Aiming at the phenomenon of mesh distortion and axial profile measurement in the traditional method, the 3D digital image correlation method (3D-DIC) was used to obtain and reconstruct the bulging contour of 5A02 aluminum alloy. The mechanical model of free bulging region was established, the calculation formula of wall thickness distribution in the bulging region was deduced, and the constitutive equation of 5A02 aluminum alloy material was obtained. The comparison was verified by finite element method, the results show that the maximum relative error of the power exponential constitutive equation is less than 10%, the maximum relative error of the contour is less than 1.5%, and the maximum relative error of the wall thickness is less than 2%. Finally, the left forming limit curve (FLC) was obtained by controlling the aspect ratio of free area.