摘要
针对实验估计Lamb波频散特性需要借助传感器阵列或空间密集采样的问题,提出了一种基于离散解析互相关的频散特性估计方法。采用一发一收法,移动接收换能器在两个相邻位置采集Lamb波响应信号;计算两组响应信号之间以及原始激励信号与响应信号之间的离散解析互相关、估计欲知模态的群延迟和相延迟;在此基础上,求得该模态的群速度和相速度频散曲线。数值仿真和实验结果表明:当信噪比在15 dB以上时,离散解析互相关法估计A 0模态和S 0模态频散特性的最大相对误差在1%左右。该方法在待测结构几何参数和材料属性未知的情况下,仅需经过两次测试就可实现Lamb波频散特性的精确估计,测试和计算效率高,能够满足实际工程应用。
A discrete analytic cross-correlation method for the estimation of the dispersion characteristic of Lamb waves is proposed to deal with the problem that conventional experimental estimation of the dispersion characteristics of Lamb waves is often realized by means of sensor array or intensive sampling in a space.A transducer serving as the receiver is placed at two adjacent positions to collect signals of Lamb wave response by using the pitch-catch technique.The group delay and phase delay of wave packets are estimated by calculating the discrete analytic cross-correlation between two response signals and between the original excitation signals and the response signals.On this basis,dispersion curves of both the group velocity and phase velocity of desired modes are simultaneously obtained.Numerical and experimental results show that when the signal-to-noise ratio is above 15 dB,the maximum relative error of A 0 mode and S 0 mode estimated by the discrete analytic cross-correlation method is about 1%.In the case that the prior knowledge of geometric parameters and material properties of the structure to be inspected is unknown,the method accurately estimates the Lamb wave dispersion characteristics with only two tests.It is the high efficiency of test and calculation that the discrete analytic cross-correlation method fully satisfies the engineering demand.
作者
牛祥祥
曹徐伟
曾亮
NIU Xiangxiang;CAO Xuwei;ZENG Liang(School of Mechanical Engineering,Xi’an Jiaotong University,Xi’an 710049,China)
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2019年第10期159-166,共8页
Journal of Xi'an Jiaotong University
基金
国家自然科学基金资助项目（51875435）
中国博士后科学基金资助项目（2018M643627）
河南省水下智能装备重点实验室开放基金资助项目（KL03A1804）
关键词
LAMB波
频散
解析互相关
群延迟
相延迟
Lamb wave
dispersion
analytic cross-correlation
group delay
phase delay
