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.%To overcome the shortcomings of linear Lamb waves in closed crack and micro crack monitoring,a imaging method of crack damage localization in plate-like structure based on vibro-acoustic modulation theory and delay and sum algorithm is proposed.The signal components of acoustic wave are analyzed in the crack structure when there is only high-frequency (HF) excitation and there are low-frequency (LF) and HF excitation at the same time.And then,a signal extraction technology is put forward to extract the signal containing damage information.Fatigue crack is located and imaged in plate-like structure based on delay and sum algorithm referring to linear Lamb wave damage localization method.Experiments prove that the proposed method can locate the crack position effectively without the original health reference signal,which provides a way for contact-like damage localization and imaging.
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