Local ultrasonic resonance spectroscopy (LURS) is a new approach to ultrasound signal analysis, which was necessitated by a novel inspection method capable of the contact-free, localized, broadband generation and detection of ultrasound. By performing a LURS scan, it is possible to detect local mechanical resonances of various features and of the specimen itself. They are highly sensitive to local mechanical properties. By observing different parameters in the frequency spectrum (e.g., resonance amplitude and resonance peak frequency), geometrical, material and condition properties can be visualized for all of the scanning positions. We demonstrate LURS for inspection of a carbon fiber reinforced polymer plate. Local defect resonances of delaminations and a flat-bottom hole were detected in the frequency range from 25 to 110 kHz. Analyzing the higher frequency range (0.3 MHz to 1.5 MHz) of the same scan, the shift of the thickness resonance frequency of the plate and its higher-order resonance frequencies carry the information about the aluminum inclusions. LURS shows an advantage in characterizing the localized features of the specimens via contact-free ultrasonic inspection.

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局部超声共振光谱：板材检测演示

局部超声共振光谱 (LURS) 是一种新的超声信号分析方法，它是一种能够非接触式、局部化、宽带产生和检测超声的新型检测方法所必需的。通过执行 LURS 扫描，可以检测各种特征和样本本身的局部机械共振。它们对局部机械性能高度敏感。通过观察频谱中的不同参数（例如，共振幅度和共振峰值频率），可以对所有扫描位置的几何、材料和条件特性进行可视化。我们展示了用于检查碳纤维增强聚合物板的 LURS。在 25 到 110 kHz 的频率范围内检测到分层和平底孔的局部缺陷共振。分析同一扫描的较高频率范围（0.3 MHz至1.5 MHz），板的厚度共振频率及其高阶共振频率的偏移携带了有关铝夹杂物的信息。LURS 在通过非接触式超声波检测表征样品的局部特征方面具有优势。