超声回波法海底管道外涂层检测技术

Detection technology for submarine pipeline’s outer coating based on ultrasonic echo method

外防腐层失效是管道腐蚀的重要诱因,对管道外防腐层进行有效检测至关重要,而常见的埋地管道外检测技术很难应用到海底管道。采用数值模拟与试验相结合的方式对管道外涂层超声波检测技术进行研究,建立超声波在管道结构中传播的有限元模型,验证超声波应用于管道涂层检测的可行性;进行超声波涂层检测静态试验,提取超声回波的响应特性并采用小波分析法对回波信号进行降噪;搭建管道外涂层缺陷连续检测室内试验平台,实现管道外涂层缺陷的准确识别。结果表明:超声回波幅值差异能够作为涂层缺陷的判别标准,该检测技术可有效地识别管道的外涂层缺陷,具有较高的检测灵敏度。

The failure of the external coating is an important cause of pipeline corrosion,and effective detection of the pipeline’s outer coating is very essential.However,the common external detection technology used for the buried pipeline is difficult to be applied to the submarine pipeline.Therefore,the method by combining the numerical simulation and experiment was applied to study the ultrasonic detection technology for the pipeline’s outer coating.Firstly,a finite element model of ultrasonic propagation in the pipeline structure was established to verify the feasibility of the ultrasonic detection technology for the pipeline coating.Then,the ultrasonic detection static test for coating was carried out,where the response characteristics of the ultrasonic echo was extracted and the echo signal was denoised by the wavelet analysis approach.The indoor experimental platform suitable for continuous detection of defects of the pipeline’s coating was built,and was successfully identified.The results show that the difference of the ultrasonic echo amplitude can be used as a criterion for identifying coating defects,and this detection technology can efficiently identify the external coating’s defects of the pipeline,with a high detection sensitivity.