摘要
为了解决传统压电超声换能器检测方式耦合不稳定的问题,将电磁超声应用于多层粘接结构界面检测。针对电磁超声界面检测信号噪声高和盲区大的问题,在电磁声换能原理和盲区成因分析的基础上,用小波阈值滤波和自适应抵消滤波方法对检测信号进行了处理,达到了降低信号噪声和减小盲区的目的。对钢板和双层橡胶粘接样品的回波信号处理结果表明:小波阈值滤波将信噪比提高了约12 dB,自适应抵消滤波有效地减小了由感生信号产生的盲区。
The electromagnetic ultrasound is used in the detection of interfaces of the adhesive multilayer structures to solve the unstable coupling problem in ultrasonic testing by traditional piezoelectric transducers. Based on the analysis of the transforming mechanism of electromagnetic ultrasound energy and the resultant dead zone from mutual inductance of the transducer, the wavelet filtering by soft-thresholding and adaptive noise canceling methods are used simultaneously to the detected electromagnetic ultrasonic signals to overcome the drawbacks of the low signal to noise ratio （SNR） and the wide intrinsic dead zone of the transducer. Processed results in the interface detection of a three layered adhesive sample of steel and rubber materials demonstrate that the wavelet filtering enhances the SNR about 12 dB while the adaptive noise canceling narrows the dead zone effectively.
出处
《声学学报》
EI
CSCD
北大核心
2007年第3期226-231,共6页
Acta Acustica
基金
国家自然科学基金资助项目(10234060
10574138
10474113)
关键词
检测信号
电磁超声
去噪方法
压电超声换能器
多界面
自适应抵消
多层粘接结构
回波信号处理
Acoustic noise
Electromagnetic wave reflection
Inductance
Interfaces (materials)
Noise abatement
Piezoelectric transducers
Signal detection
Signal to noise ratio
Ultrasonic reflection
Ultrasonic testing
Ultrasonic waves
