211 非線形波動変調によって生じる復調波動の波動伝播解析に基づく接触面を有する損傷の位置推定(セッション7 構造物診断技術) [in Japanese] 211 Damage Localization Based on Propagation Analysis of Demodulation Wave Caused by Nonlinear Wave Modulation [in Japanese]
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This study concerns damage localization method based on nonlinear wave modulation phenomenon. The detection technique based on nonlinear wave modulation is one of sensitive technique as nondestructive detection technique. When the structure including contact-type failure is vibrating at low-frequency, the pair of contact surfaces is tapping and clapping. In this condition, the scatter characteristics of high-frequency waves, such as wave transmissivity and reflectivity, in the vicinity of the contact-type failure may fluctuate in synchronization with low-frequency vibration. Since the demodulation wave propagates through the structure with the group velocity, it is possible to estimate location of the contact-type failure. When impact excitation is used as low-frequency vibration, we are able to observe the initial achieved waves which is occurred at the location of the contact-type failure. In this paper, we use the dispersion wave as high-frequency waves, so we need to evaluate the propagation characteristics of demodulated swave by theoretical analysis based on Bernoulli-Euler beam. Especially, the equation which describes propagation characteristics of demodulated waves is applied and the relationship of dispersion of equation of demodulated waves is determined. Finally, we evaluate the relationship between propagation distance and the collapse of the wave packet and verified the limit of the proposed method caused by the collapse of the wave packet in theory.
- The Proceedings of the Symposium on Evaluation and Diagnosis
The Proceedings of the Symposium on Evaluation and Diagnosis 2014.13(0), 127-130, 2014
The Japan Society of Mechanical Engineers