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

Key words:  submarine pipeline  corrosion  coating detection  ultrasonic echo

Abstract:

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.