管道导波时反聚焦检测系统的设计与实现  

Design and implementation of time reversal focusing inspection system for guided wave in pipeline

作　　者：何存富[1] 周进节[1] 吴斌[1] 郑阳[1] 符浩[1] 

机构地区：[1]北京工业大学机械工程与应用电子技术学院,北京100124

出　　处：《仪器仪表学报》2012年第2期342-348,共7页Chinese Journal of Scientific Instrument

基　　金：国家自然科学基金(10772009)资助项目

摘　　要：在分析管道中超声导波时反聚焦原理的基础上,设计并实现了一套适合激励压电换能器阵列,并对管道中超声导波能量在缺陷处进行时间-空间聚焦的时反聚焦检测系统。该系统实现的关键技术为:改进DDS(direct digital synthesis)结构,实现脉冲激励电路对时反特征信号进行合成发射;采用脉冲方式,实现小体积大输出功率的宽带线性功放电路;通过时反聚焦检测过程,实现管道中超声导波能量在缺陷处的时间-空间聚焦。采用该系统进行八通道时反聚焦检测实验,其结果表明,对于所用的含缺陷的管道而言,在特定的检测条件下,缺陷回波信号的幅值相对常规检测可提高246%,并且很好地抑制了导波的频散和多模态特性,提高了回波信号的信噪比。A temporal-spatial focusing inspection system for ultrasonic guided wave in pipeline based on time reversal focusing theory is presented in this paper. The system can be used to excite piezoelectric transducer arrays and focus the energy of guided waves at flaw. The key design techniques of this system are： an excitation circuit, which is based on the improved direct digital synthesis （DDS） for synthesizing and emitting time reversal signal, and a small size wide band pulse amplifier with high power output and linear features. With this system, the signal echoed from the crack can be enhanced based on time reversal temporal-spatial focusing effect. Under particular test conditions, experimental work using a transducer array with eight channels was carried out in a pipeline with an artificial flaw. The result shows that the amplitude of the echo signal from the flaw increases by 246% compared with that of the normal test signal. In addition, the signals obtained from the temporal-spatial focusing process have a higher signal to noise ratio, and the dispersion and muhimode that occur in normal test signal are restrained.

关 键 词：超声导波 时反聚焦 检测系统 

分 类 号：TB51[理学—物理]