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针对线性Lamb波在监测闭合裂纹及微裂纹方面的不足,基于振动声调制理论,提出了一套板类结构中裂纹损伤定位方法。通过分析仅有高频(HF)激励和高低频(HF和LF)同时激励时,声波在含裂纹结构中的传播路径及其信号成分组成,提出了一种含损伤信息信号的提取技术,继而结合延时叠加算法,参考有基准的线性Lamb波损伤定位方法,对板类结构中的疲劳裂纹进行了定位成像。试验证明,该方法可在无需原始健康基准信号的前提下,有效定位出平板结构中的疲劳裂纹,为结构中接触类损伤的定位成像提供了思路。
Aiming at the shortage of linear Lamb wave in monitoring closed crack and micro crack, a set of crack damage location method in plate structure is proposed based on the theory of vibrational sound modulation. By analyzing the propagation paths of sound waves in a cracked structure and the composition of the signal components only when high-frequency excitation (HF) and high-low-frequency (HF and LF) excitation are simultaneously excited, an extraction technique of damage information signals is proposed, Combined with the time delay superposition algorithm, reference is made to the linear Lamb wave damage location method with reference to locate and image the fatigue crack in the plate structure. Experiments show that this method can effectively locate the fatigue crack in the flat plate structure without the need of the original health reference signal, and provide a way for the positioning imaging of the contact damage in the structure.