摘要
针对超声导波的多模态和频散特性会导致信号波包在结构中传播发生展宽的现象,研究了400 kHz时的管道导波时域信号。指出了用时频分析方法可以直观地描述导波信号在传播过程中的能量分布,准确反映主要模态信息和各模态群速度变化趋势,建立与导波频散曲线间的对应关系,并且利用时频重排的方法可以进一步提高分析结果的可读性。
The multi-modes and dispersive effect of ultrasonic guided wave leads to the spreading of the wavepacket propagated in a structure. The signal of ultrasonic guided wave propagated in a pipe at 400 kHz are studied. Results show that time-frequency analysis method can be used to describe the energy distribution of guided wave signal , give the main modes information and show the trend of group velocity changes. From these, the corresponding relation between the signal in time space and group velocity dispersion curves can be established. A reassignment method for nonstationary time-frequency analysis creates a modified version of a representation by moving its values away from where they are computed, so as to procluee a better localization of the signal components and improve the readability of the representation in the study.
出处
《无损检测》
北大核心
2006年第7期337-340,共4页
Nondestructive Testing
基金
国家自然科学基金项目(10272007
10372009
60404017)
北京市自然科学基金项目(4052008)
北京市教委资助项目(KZ200510005004
KM200310005012)
关键词
时频分析
重排
导波信号
频散
Time-frequency analysis
Reassignment
Guided-wave signal
Dispersion
