基于编解码的超声导波轨底裂纹识别方法研究

超声导波在针对钢轨小裂纹检测时由于利用高频信号，会导致信号衰减明显，对于小裂纹的检测灵敏度降低，针对细小裂纹难以识别，为提高缺陷信号识别度，本文将barker码作为编码方式，并用类BPSK作为解码方式，利用到导波检测钢轨小裂纹的信号处理中。通过实验将对钢轨轨底上深度6 mm宽度0.5 mm的人工裂纹进行验证，为衡量算法效果分别用未经过任何信号处理的原始收发导波信号和经过barker码-匹配滤波编解码处理的导波信号与实验方法进行对比。结果表明，利用barker码-类BPSK编解码处理的导波信号在处理钢轨轨底小裂纹的识别上有着明显的增强作用，效果优于另外两种方法，可以为以后的导波钢轨小裂纹检测提供支持。

Research on the identification method of small cracks on the bottom of ultrasonic guided waves based on codec

Ultrasonic guided waves use high frequency signals in the detection of small cracks in rails, which will lead to significant signal attenuation and reduced detection sensitivity for small cracks. It is difficult to identify small cracks. In order to improve the recognition of defect signals, this paper uses barker code as the encoding method, and use BPSK-like as a decoding method, which is used in the signal processing of guided wave detection of small cracks in rails. The artificial crack with a depth of 6 mm and a width of 0.5 mm on the rail bottom will be verified through experiments. In order to measure the effect of the algorithm, the original transceiver guided wave signal without any signal processing and the guided wave signal processed by the barker code-matched filter codec are used respectively. Compare with the experimental method. The results show that the guided wave signal processed by the barker code-like BPSK codec has an obvious enhancement effect on the identification of small cracks at the bottom of the rail, and the effect is better than the other two methods, which can be used for the detection of small cracks in the guided rail in the future. provide support.