This paper aims to explore a new technique for structural damage identification using cubic spline interpolation. The method is based on the interpolation of modal rotations measured with shearography, making use of the analytical derivative of the spline to compute the modal curvature, which is known to be very sensitive to damage. As a means of reducing noise and measurement uncertainty propagation to a minimum, an expression for an optimal spatial sampling is derived. Furthermore, a baseline-free damage factor, allied with an optimal sampling, is also introduced. The proposed identification method is validated using experimental data of a beam. Using a damage localisation quality index, a comparison between the present method and one using finite differences is carried out, showing that the differentiation of spline interpolation leads to better damage identifications. The results obtained with the proposed approach show robustness and consistency in the localisations. Additionally, the hurdles of identifying small and multiple damage are tackled with the proposed method, yielding a good performance.

中文翻译：

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优化空间采样三次样条插值在损伤识别中的应用

本文旨在探索一种使用三次样条插值进行结构损伤识别的新技术。该方法基于使用剪切成像测量的模态旋转插值，利用样条的解析导数来计算模态曲率，众所周知，模态曲率对损坏非常敏感。作为将噪声和测量不确定性传播降至最低的一种手段，导出了最佳空间采样的表达式。此外，还引入了与最佳采样相结合的无基线损伤因子。使用梁的实验数据验证了所提出的识别方法。使用损伤定位质量指标，将本方法与使用有限差分的方法进行比较，表明样条插值的微分导致更好的损伤识别。使用所提出的方法获得的结果显示了本地化的稳健性和一致性。此外，所提出的方法解决了识别小损伤和多重损伤的障碍，产生了良好的性能。