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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价，并通过细观力学和弹性动力学分析对其进行合理的理论解释，从而为建立此类界面的非线性超声表征或监测方法做出贡献。首先，基于非线性界面模型，对非线性超声效应产生谐波的微扰分析进行了更严格的推导，阐明了非线性压力-间隙关系与二次谐波幅值之间的关系。其次，基于使用激光多普勒测振仪的振动速度测量，已经建立了一种方法，该方法将压电换能器的电压输出转换为位移振幅，以及校正换能器的灵敏度的频率依赖性。这使得定量实验成为可能， ...更多信息对接触界面处的谐波产生特性进行了心理评价，并将实验数据与理论预测进行了定量比较。第三，根据局部刚度的空间不均匀性以及界面处的粘性损失，讨论了从体波和界面波测量获得的界面刚度的频率依赖性。最后，通过测量不同接触压力下板中Lamb波速度波形的高次谐波，对部分接触条件下板中非线性Lamb波的沿着传播特性进行了初步研究。结果发现，三次谐波的产生是本实验中的一个显著特征。这些发现被认为是有意义的，在建立一个新的表征方法的基础上，不仅体波，但也导波，如瑞利或兰姆波的非线性超声特性的不完美的界面。少