利用直接激发Rayleigh表面波的方法测量材料的声学非线性系数  

Evaluation of the acoustic nonlinearity parameter of materials with Rayleigh waves excited directly

作　　者：税国双[1] 汪越胜[1] Jianmin Qu Jin-Yeon Kim Laurence J. Jacobs 

机构地区：[1]北京交通大学力学所,北京100044 [2]School of Mechanical Engineering, Georgia Institute of Technology Atlanta, Georgia 30332-0405, USA

出　　处：《声学学报》2008年第4期378-384,共7页Acta Acustica

基　　金：国家自然科学基金(10228204)

摘　　要：提出了利用直接激发Rayleigh表面波的方法测量材料的声学非线性系数。采用专门的信号源,将压电传感器安装在试件边缘直接激发Rayleigh表面波,利用激光干涉仪测量系统采集试件表面的Rayleigh波信号。对采集到的Rayleigh波信号进行FFT变换,得到Rayleigh波信号中所包含的基频和高频成分,并据此进一步确定材料的声学非线性系数。对铝合金材料AA2024和AA6061的试验测量与分析结果表明,这种利用将压电传感器直接安装在试件边缘激发Rayleigh表面波的方法能够有效、准确地测量材料的声学非线性系数,可以为材料和结构早期力学性能退化的无损检测和评价提供一种有效的途径。An experimental technique for the determination of the acoustic nonlinearity parameters of materials with Rayleigh waves excited directly is presented. Rayleigh surface waves were generated in materials by exciting at the specimen＇s edge with a special gated amplifier, and the propagating Rayleigh waves were measured with a laser interferometer system. After the Rayleigh wave signals were processed with FFT method, the acoustic nonlinearity parameters of materials were then determined from the absolute magnitudes of the fundamental and second harmonics of Rayleigh surface waves. This procedure was used to determine the acoustic nonlinearity parameters of aluminum alloy 2024 and 6061. It is shown that the results compare well with those available in the literature, this method thus can be used to evaluate the acoustic nonlinearity parameters of materials effectively. This technique can provide a practical way in the nondestructive characterization of the degradation of materials and structures in the early fatigue life.

关 键 词：Rayleigh表面波 干涉仪测量系统 铝合金材料 非线性系数 RAYLEIGH波 声学 激发 传感器安装 

分 类 号：O422.7[理学—声学]