Quantitative Evaluation and Micromechanical/Elastodynamic Analysis of Nonlinear Ultrasonic Properties of Contacting and Weak Interfaces

接触界面和弱界面非线性超声特性的定量评估和微机械/弹性动力学分析

基本信息

批准号：
18560079
负责人：
BIWA Shiro
金额：
$ 2.39万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

This research has been carried out to make a quantitative evaluation of nonlinear ultrasonic characteristics of contacting/weak-bonding interfaces as well as to give a sound theoretical explanation to them by micromechanical and elastodynamic analyses, thereby to contribute to the establishment of nonlinear ultrasonic characterization or monitoring method for these interfaces. First, the perturbation analysis of harmonic generation due to nonlinear ultrasonic effect has been reformulated in a more rigorous way based on a nonlinear interface model, and the relation between the nonlinear pressure-gap relation and the second harmonic amplitude has been clarified. Second, based on the vibration velocity measurement using a laser-Doppler vibrometer, a method has been established which converts the voltage output of a piezoelectric transducer to the displacement amplitude, as well as corrects for the frequency dependence of the transducer's sensitivity. This has enabled a quantitative experi … More mental evaluation of harmonic generation characteristics at contacting interface, and a quantitative comparison between the experimental data and the theoretical prediction. Third, the frequency dependence of the interfacial stiffnesses obtained from the bulk and interface wave measurements has been discussed in the light of spatial inhomogeneity of local stiffness as well as the viscous loss at the interface. Finally, a preliminary study has been carried out for nonlinear Lamb wave propagation characteristics along a plate under partial contact conditions, by measuring the higher harmonics in the velocity waveforms of the Lamb wave in a plate under different contact pressures. As a result, the generation of the third harmonics has been found to be a remarkable feature in this experiment. These findings are considered to be meaningful in the view of establishing a new characterization method for imperfect interfaces based on nonlinear ultrasonic characteristics of not only bulk waves but also guided waves such as Rayleigh or Lamb waves. Less

本研究旨在对接触/弱结合界面的非线性超声特性进行定量评估，并通过微观力学和弹性动力学分析对其进行合理的理论解释，从而有助于建立非线性超声表征或监测首先，基于非线性界面模型，以更严格的方式重新表述了由于非线性超声效应而产生的谐波的扰动分析，以及这些界面之间的关系。其次，基于激光多普勒测振仪的振动速度测量，建立了一种将压电传感器的电压输出转换为位移幅度的方法。作为对传感器灵敏度的频率依赖性的校正，这使得能够对接触界面处的定量谐波定量生成特性进行实验评估，以及实验数据与理论预测之间的比较。根据局部刚度的空间不均匀性以及界面处的粘性损失，讨论了体波和界面波测量中界面刚度的频率依赖性。最后，对获得的非线性兰姆波传播进行了初步研究。通过测量不同接触压力下板中兰姆波速度波形的高次谐波，研究了部分接触条件下沿板的特性，结果发现三次谐波的产生。该实验的一个显着特点是，鉴于建立一种基于体波和导波（如瑞利波或兰姆波）的非线性超声特性的新的不完美界面表征方法是有意义的。