摘要
基于小波变换和模态声发射理论,通过模态声发射试验的方法确定了管道中导波传播的频散特性。通过分析声发射信号的Gabor小波变换幅度在时频空间分布特点,确定某一频率下某一模态导波到达传感器的时间,从而确定该频率下该模态导波的群速度,进而确定其频散曲线。试验确定管道中频散曲线与理论计算曲线较好吻合,证明小波变换是分析频散波时频特性的有效工具。
Based on the wavelet transformation and the theory of modal acoustic emission, the dispersion of guided wave propagated in thin plate was investigated by acoustic emission experiment. The wavelet transformation by using the Gabor wavelet is applied to the time-frequency analysis of disperse plate waves. It is shown that the peaks of the magnitude of WT in the time-frequency domain are related to the arrival times of guided waves. By utilizing the time-frequency data of the WT,the frequency-dependent arrival times of some modal guided waves to sensors are obtained. As a result, the dispersion characteristics of guided waves are known. It is demonstrated the wavelet transformation is an effective tool of analyzing the time-frequency characteristic of disperse wave.
出处
《管道技术与设备》
CAS
2005年第4期14-16,39,共4页
Pipeline Technique and Equipment
基金
国家自然科学基金资助项目(19972003)
北京市自然科学基金重点项目(3011001)
关键词
小波变换
模态声发射
导波
频散
wavelet transformation
modal acoustic emission
guided waves
disperse
