Damage identification for beam-like structures based on proper orthogonal modes of guided wavefields
Damage identification for beam-like structures based on proper orthogonal modes of guided wavefields
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DOI：
10.1016/j.ymssp.2022.110052
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发表时间：
2023-04
影响因子：
8.4
通讯作者：
Wei Zhou;Y.F. Xu
中科院分区：
文献类型：
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作者：
Wei Zhou;Y.F. Xu
结构损伤会引起导波在损伤区域的反射，从而导致导波场的局部异常。如果结构在几何上是光滑的，并且由没有刚度和质量不连续的材料制成，这些局部异常可以用于无基线损伤识别。近年来，人们研究了基于导波场的损伤识别方法，通过在时间和频率波数域中提取和定位导波场的局部异常。同时，对基于振动损伤识别的适当正交模态进行了研究。本文研究了导波场POMs在类梁结构损伤识别中的有效性。由于POMs的局部异常可以被POMs的全球趋势所覆盖，因此采用连续小波变换来抑制全球趋势，增强局部异常。解释了适当阶次高斯小波函数的连续小波变换抑制POMs全局趋势和增强POMs局部异常的基本机理。采用自适应截断技术确定用于损伤识别的重要点。根据模态保证判据和统计判据确定高斯小波函数的适当阶数，即它们的消失矩数。采用适当阶高斯小波函数对重要损伤点进行连续小波变换，得到累积损伤指数。对损伤的类梁结构进行了数值和实验研究。结果表明，本文提出的方法对于识别梁状结构的损伤位置和程度具有准确和抗噪性。
Damage in structures can cause local anomalies in a guided wavefield due to reflection of guided waves in neighborhoods of damage. These local anomalies can be used for baseline-free damage identification if the structures are geometrically smooth and made of materials that have no stiffness and mass discontinuities. Recently, guided wavefield-based methods have been studied for damage identification by extracting and localizing local anomalies in guided wavefields in the time- and frequency–wavenumber domains. Meanwhile, proper orthogonal modes (POMs) obtained by the proper orthogonal decomposition have been studied for vibration-based damage identification. In this paper, the effectiveness of POMs of guided wavefields for damage identification in beam-like structures is studied. Since local anomalies in the POMs can be covered by global trends of the POMs, the continuous wavelet transform is used to suppress the global trends and intensify the local anomalies. The fundamental mechanism of how the continuous wavelet transform with Gaussian wavelet functions of a proper order can suppress the global trends of POMs and intensify local anomalies of POMs is explained. Significant POMs used for damage identification are determined by an adaptive truncation technique. The proper orders of the Gaussian wavelet functions, i.e., their number of vanishing moments, are determined based on the modal assurance criterion and a statistical criterion. The continuous wavelet transform of the significant POMs with Gaussian wavelet functions of the proper orders is used to yield an accumulative damage index. Numerical and experimental investigations of the proposed method are conducted on damaged beam-like structures. Their results verified that the proposed method is accurate and noise-robust for identifying the location and extent of damage in beam-like structures.