Abstract Shear cutting is a prominent process in the chipless separation of metallic sheet materials. The cutting surface characteristics are the basis for quality assessment. Many present investigations deal with part quality and the influence of different process parameters, i.e., cutting edge geometry, punching speed and die clearance. Material failure occurs when the material's forming limit is reached, which depends on the deformation and the stress state. Here, strain and strain rate primarily drive material behavior and interact in the shear affected zone. An overall analysis of the complex cause-effect relationships has not been possible until now. Hence, an experimental setup enabling a detailed evaluation of the shear zone is presented. First, a shear cutting tool is introduced, which allows an in situ high resolution analysis of the material deformation in the shear affected zone under plain strain conditions. Based on the recorded high speed images, strains and strain rates are derived using classical block matching, the digital image correlation, and a tailored image handling routine. Further, for the first time, crack initiation and propagation could be recorded and evaluated using a new optical flow model with total generalized variation prior.

中文翻译：

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剪切切削中应变、应变率和裂纹演化的测量

摘要 剪切切割是金属板材无屑分离的一个重要过程。切割表面特性是质量评估的基础。目前的许多研究涉及零件质量和不同工艺参数的影响，即切削刃几何形状、冲压速度和模具间隙。当达到材料的成形极限时会发生材料失效，这取决于变形和应力状态。在这里，应变和应变率主要驱动材料行为并在剪切影响区相互作用。直到现在才可能对复杂的因果关系进行全面分析。因此，提出了一种能够对剪切区进行详细评估的实验装置。首先介绍一个剪切刀具，这允许在平面应变条件下对剪切影响区中的材料变形进行原位高分辨率分析。基于记录的高速图像，使用经典块匹配、数字图像相关性和定制的图像处理程序导出应变和应变率。此外，首次可以使用具有总广义变化先验的新光流模型来记录和评估裂纹萌生和扩展。