纵波在含有线性粘滞粘接层的粘接结构中的传播

研究了纵波垂直入射上下基体为同种介质且含有线性粘滞粘接层的三层板状粘接结构时声波的反射和透射特性,基于粘接界面的准静态模型(QSM)并结合各向同性线性粘滞体的本构方程,导出了含有粘滞系数和体积弹性模量的纵波反射和透射系数表达式。首先将纵波的准静态模型解和精确解进行对比,研究了准静态模型的适用条件。其次在界面处于不同接触形式(完好连接和粘滞型弱粘接)的情况下,分别讨论了考虑和不考虑界面相对质量对声反射和透射特性的影响。接着分析了粘滞粘接层参数的变化对纵波反射和透射特性的影响。最后在不大于0.1 MHz-mm的较小频厚积范围内简要阐述了如何鉴别界面形式。结果表明,准静态模型适用于较小频厚积的检测;是否考虑界面的相对质量对纵波的反射和透射特性影响不大;在特定的频厚积下,利用纵波的反射或透射系数方法结合准静态模型可有效辨别界面形式。研究成果可为实验时采用纵波垂直入射检测粘接结构提供一定的理论参考。

Propagation of longitudinal wave in adhesive structure with linear viscous adhesive layer

The reflection and transmission properties of acoustic wave in the trilaminar plate-like adhesive structure with a linear viscous adhesive layer and the upper and lower substrates were the same kind of material were studied when longitudinal wave vertical incident.Based on the quasi-static model (QSM) of the adhesive interface and the constitutive equation of the isotropic linear viscous body,the expressions of the longitudinal wave reflection and transmission coefficients with the coefficient of viscosity and bulk modulus were derived.Firstly,the QSM and the exact solutions of the longitudinal wave were compared with each other to explain the applicable conditions of the QSM.Secondly,the effects of relative quality of interface on acoustic wave reflection and transmission coefficients were considered,by taking and not taking the fore-mentioned factor into consideration,under the condition of different interface contact forms (perfect connection and viscous weak bonding).Then,the influence of parameters changes of viscous adhesive layer on the reflection and transmission properties of the longitudinal wave was analyzed.Finally,the method of identifying the interface form in smaller frequency-thickness product range which was less than 0.1 MHz-mm was briefly interpreted.The results show that the QSM is suitable for the detection of smaller frequency-thickness product.Whether the relative mass of the interface is considered has little effect on the reflection and transmission characteristics of the longitudinal wave.The interface forms could be effectively identified by using the method of reflection or transmission coefficient of longitudinal wave combined with QSM at specific frequencythickness product.The research results could provide a theoretical reference for the detection of the adhesive structure by longitudinal wave vertical incident.