This paper demonstrates the use of broad-band phase based motion magnification (PMM) to improve the modal parameter estimation from high-speed stereoscopic digital image correlation (DIC). PMM is used as a diagnostic technique to investigate the free vibration response of a panel. The compliant panel, consisting of a thin polycarbonate sheet, forms a test section wall in a supersonic blow-down wind tunnel, where it is used to investigate supersonic fluid-structure interaction in the presence of shock wave boundary layer interaction. The panel is excited by an impact hammer and the transient deformation is captured using high-speed cameras. The original and motion-magnified images are input to a digital image correlation algorithm to calculate the out-of-plane deformation of the panel. The measured deformation is used to extract the modal parameters of the compliant panel. By using PMM as a preprocessing tool in a broad frequency band containing multiple structural modes, the signal to noise ratio of the measured deformation is improved. The use of PMM improves the estimated mode shapes, increasing the MAC value of the first mode compared to FEM predictions from 0.29 to 0.99. Motion magnification also improves the coherence between measured input force and panel deformation by up to 13% if suitable parameters are chosen.

中文翻译：

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使用基于相位的运动放大和立体数字图像相关性的兼容面板的模态参数估计

本文演示了使用宽带相位运动放大 (PMM) 来改进高速立体数字图像相关 (DIC) 的模态参数估计。PMM 用作诊断技术来研究面板的自由振动响应。柔性面板由聚碳酸酯薄板组成，在超音速吹扫风洞中形成测试部分壁，用于研究存在冲击波边界层相互作用时的超音速流固耦合。面板由冲击锤激发，并使用高速摄像机捕获瞬态变形。原始图像和运动放大图像被输入到数字图像相关算法中，以计算面板的平面外变形。测量的变形用于提取柔性面板的模态参数。通过在包含多种结构模式的宽频带中使用 PMM 作为预处理工具，提高了测量变形的信噪比。PMM 的使用改进了估计的模式形状，与 FEM 预测相比，第一模式的 MAC 值从 0.29 增加到 0.99。如果选择合适的参数，运动放大还可以将测量的输入力和面板变形之间的一致性提高 13%。与 FEM 预测相比，将第一种模式的 MAC 值从 0.29 增加到 0.99。如果选择合适的参数，运动放大还可以将测量的输入力和面板变形之间的一致性提高 13%。与 FEM 预测相比，将第一模式的 MAC 值从 0.29 增加到 0.99。如果选择合适的参数，运动放大还可以将测量的输入力和面板变形之间的一致性提高 13%。