On the reflection of coupled Rayleigh-like waves at surface defects in plates.
On the reflection of coupled Rayleigh-like waves at surface defects in plates.
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DOI：
10.1121/1.2805668
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发表时间：
2008-01
期刊：
影响因子：
--
通讯作者：
B. Masserey;P. Fromme
中科院分区：
文献类型：
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作者：
B. Masserey;P. Fromme
基于解析模型和有限差分模拟，对弹性板表面缺陷耦合瑞利波的反射进行了实验研究和分析。瑞利波在板块中传播的特点是能量传递到板块的另一侧，并在一段称为拍长的距离内传递回来。实验结果清楚地显示了这种加热效应及其对频率-厚度积的依赖关系，与已有的分析预测结果非常吻合。对于构成入射瑞利波的基本A(0)和S(0) Lamb模式，分别对传播和散射进行了建模。利用有限差分模拟方法研究了表面缝隙的反射系数，通过叠加得到了反射的瑞利波。理论模型表明，反射场与激发距离与拍长之比以及特定高兰姆模的截止频率有很强的相关性。标准脉冲回波测量允许从远程换能器位置检测小缺陷。反射瑞利波的预测振幅谱与实测振幅谱吻合较好。开发的模型允许使用飞行时间和频率测量的组合来评估缺陷位置和损坏的板侧。
The reflection of coupled Rayleigh-like waves from surface defects in elastic plates is investigated experimentally and analyzed on the basis of an analytical model and finite difference simulations. The propagation of Rayleigh-like waves in plates is characterized by an energy transfer to the opposite plate side and back over a distance called the beat length. Experimental results clearly show this beating effect and its dependency on the frequency-thickness product, and excellent agreement is obtained with existing analytical predictions. The propagation and scattering are modeled separately for the fundamental A(0) and S(0) Lamb modes that constitute the incident Rayleigh-like wave. The reflection coefficients from surface slots are investigated using finite difference simulations and the reflected Rayleigh-like wave is obtained by superposition. The theoretical model reveals strong dependencies of the reflected field on the ratio between excitation distance and beat length and on the cutoff frequencies of specific higher Lamb modes. Standard pulse-echo measurements allow for the detection of small defects from a remote transducer location. Good agreement is obtained between the predicted and measured amplitude spectra of the reflected Rayleigh-like wave. The developed model allows for the evaluation of defect location and damaged plate side using a combination of time-of-flight and frequency measurements.