提出了一种基于数字散斑相关法和双目立体视觉技术的全场三维变形测量方法,实现了对爆炸焊接制备的铜/铝复层材料的变形测量.研究了该方法所涉及的数字散斑相关算法、三维坐标、位移和应变计算等关键技术,借助于VC++6.0开发环境,研制并开发了用于铜/铝复层板全场变形测量的试验系统及其软件.为了验证本文所述测量方法的可行性,进行了精度验证实验和铜/铝复层板单向拉伸试验,且对复层板拉伸试验结果与有限元软件Abaqus数值模拟结果进行了对比分析.结果表明:本文方法的应变测量精度优于0.5％,与引伸计测得的结果基本相当；测得的应变极值分布与有限元模拟结果很吻合；在板料发生颈缩前,塑性应力-应变模拟曲线与试验结果很吻合；整个变形过程中位移-载荷模拟曲线的变化趋势与试验结果一致,模拟得到的极限载荷的相对误差为0.06％～2.25％.实验结果说明,数字散斑方法是一种精确获得复层板料全场应变的有效手段.%To measure the deformation of copper/aluminum clad metals made by explosive welding technique, a new full-field three-dimensional deformation measurement method based on the digital speckle correlation method and binocular stereovision was proposed and implemented. The related key technologies including image correlation matching, three-dimensional coordinates, displacement and strain reconstruction were investigated. Then a deformation measurement system and corresponding software were developed based on the VC++6. 0 platform. To validate the feasibility of the proposed method, a precision test and a copper/aluminum clad tensile test were conducted, and the experimental data of the test and the numerical simulation using Abaqus software were compared. Experimental results show that the accuracy of strain measurement is not lower than 0. 5%, very close to that of the extensometer. The extreme strain distribution based on digital speckle correlation method is coincident with that the finite element simulation well. Furthermore,the simulated curves of plastic stress-strain are in agreement with the experimental data before necking the sheet metal, and the tendency of simulated curves of displacement-load is consistent with the experimental data in the whole tensile processes. Moreover, the relative errors of simulated ultimate load are from 0.06% to 2. 25%. It demonstrates that the digital speckle correlation method is an effective tool to obtain the full-field strain of sheets accurately.
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