串脉冲超声导波断轨检测技术研究

Detection of Rail-Break Using Ultrasonic Guided Wave Excited by Pulse String

针对传统的钢轨断轨检测效率低、无法进行实时检测的不足,对串脉冲超声导波断轨检测方法进行了研究。首先为了增强发射能量,同时达到脉冲叠加的目的,研发了脉冲个数、脉宽、间隔均可调的高压串脉冲超声导波发射系统;为了保证接收信号的信噪比和空间精度,用匹配滤波的方法对接收信号进行脉冲压缩。采用研制的串脉冲超声导波断轨检测系统,选用SH导波换能器在钢轨上进行了检测实验。结果表明,检测系统性能稳定,经过串脉冲叠加,使接收信号的幅值约为单脉冲接收信号的3倍,经过匹配滤波后,信噪比得到明显提升。该方法的换能器置于轨腰,能够对钢轨实现在线监测。

In order to solve the problem that traditional ultrasonic detection methods of broken rails are low efficiency and not for online monitoring, the rail-break detection method using guided waves excited by pulse strings is studied. In order to enhance the emission energy, a guided wave emission system excited by pulse strings is developed. The system can transmit a pulse string with high voltage, and the number, width and interval of pulses are all adjustable. Also, the matched filtering method is used to ensure the signal-noise ratio （SNR） and accuracy of the signal received. An experiment is carried out on the rail with the system above and suitable SH guided wave transducers. The results show that the detection performance of the system is stable. After superposition of pulses, the amplitude of the signal received is increased by about three times. The matched filtering method has improved the SNR of signal significantly. In addition, the transducers placed at the waist of rail can realize online monitoring of rail.