Stereo-digital image correlation (SDIC) is used for the analysis and quantification of parasite bending stresses in a fatigue specimen due to its mounting in a misaligned load frame. The aim of this work is to provide an easy way to estimate the induced parasite bending stresses due to the load frame misalignment, using the out-of-plane displacement measurements obtained by SDIC and beam theory. Analytical solutions of parasite stresses as a function of out-of-plane misalignments are provided for flat fatigue specimens having (a) tangentially blending fillets between the uniform test section and the ends and (b) continuous radius between the ends. Simple procedures for aligning a commercial load frame in accordance with international standards are also provided. The bending stresses profile along the specimen main axis obtained by numerical simulations have shown a very good agreement with the results obtained by the analytical models. The proposed methodology could complement standard alignment techniques based on samples instrumented with strain gauges or, in their absence, even replace established procedures.

中文翻译：

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根据国际标准使用立体数字图像相关性对疲劳试验机进行校准：可行性研究

立体数字图像相关 (SDIC) 用于分析和量化疲劳试样中的寄生弯曲应力，因为它安装在未对准的载荷框架中。这项工作的目的是使用 SDIC 和梁理论获得的平面外位移测量，提供一种简单的方法来估计由于负载框架未对准引起的寄生弯曲应力。对于具有 (a) 均匀测试截面和端部之间切向混合圆角和 (b) 端部之间连续半径的扁平疲劳试样，提供了寄生应力作为平面外错位函数的解析解。还提供了根据国际标准对齐商用负载框架的简单程序。通过数值模拟获得的沿试样主轴的弯曲应力分布与分析模型获得的结果非常吻合。所提出的方法可以补充基于装有应变计的样本的标准对齐技术，或者在没有应变计的情况下，甚至可以取代既定的程序。