管道长距离超声导波模态频散现象的抑制方法研究  

Research on Restraining Dispersive Characteristics of Ultrasonic Guided Wave in a Long Pipe

作　　者：李隆涛[1] 何存富[1] 吴斌[1] 

机构地区：[1]北京工业大学机电学院,北京100022

出　　处：《数据采集与处理》2004年第3期297-301,共5页Journal of Data Acquisition and Processing

基　　金：国家自然科学基金 ( 1 9972 0 0 3;1 0 2 72 0 0 7)资助项目 ;北京市自然科学基金 ( 30 1 1 0 0 1 )重点项目 ;北京市自然科学基金 ( 3992 0 0 6)资助项目。

摘　　要：针对超声导波频散特性所导致的信号波包在结构中传播发生展宽及衰减现象 ,研究了超声导波在 2 m长管道中以特定频率 ( 77k Hz)传播时的频散现象。指出了采用圆周均匀分布传感器在管道中激励导波可以抑制其中弯曲导波模态的产生 ,同时利用信号重建激励方法以及所建立的实验系统在特定的距离上抑制了超声导波模态的频散现象。结果表明 ,本文方法有效地抑制了 77k Hz的 L( 0 ,1 )导波模态的频散现象。The dispersive effect of ultrasonic guided wave leads to the spreading and attenuation of the wave-packet propagated in a structure. The dispersive characteristics of ultrasonic guided wave propagated in a 2 m long pipe at 77 kHz are studied and the transducer distributed along the circumferential direction of pipe can restrain the generation of flexural modes. Using experimental setup and a signal regeneration technique, the dispersive effect of ultrasonic guided wave after propagating a given distance is strained. Results show that L(0,1) guided mode at 77 kHz can be made to be non-dispersed. Conclusion proves that the signal regeneration technique is feasible for restraining dispersive characteristics.

关 键 词：超声导波 信号波包 频散现象 无损检测 信号重建 激励信号 管道 

分 类 号：TB559[理学—物理]