关键词: 数字图像相关法, 成形极限曲线, 铜/铝复层板, 成形性能, 有限元方法

Abstract:

To measure the forming limit strain of Cu/Al clad metal made by explosive welding technique, a new optical measurement method based on the digital image correlation (DIC) method and binocular stereovision was proposed and implemented. The FEM results were used to verify the strain measurement accuracy of the DIC method. Based on the limit strain of Cu/Al clad metals by DIC method, the influences of heat treatment and contact status on forming limit were analyzed. Also, the interfacial and fracture structures were analyzed with SEM.The results demonstrate that the relative error of major strain between DIC method and FEM mothod is 0.1% when Cu/Al clad metals are broken, and the strain distributions agree finite element simulation results well. The forming limit of the clad with Al in the inner layer is higher than the clad with Cu in the inner layer. The formability of the annealed clad is superior to the not annealed one. The clad is broken at both sides with interface fracture.

Key words: digital image correlation, forming limit curve, Cu/Al clad metal, formability, finite element method(FEM)