Application of Alternating Current Stress Measurement Method in the Stress Detection of Long-Distance Oil Pipelines

Abstract

With the development of pipeline networks, many safety accidents were caused by pipeline stress concentration; it is of great significance to accurately monitor the pipeline stress state for maintaining pipeline safety. In this paper, based on alternating current stress measurement (ACSM) methods, a 3D simulation model of a pipeline electromagnetic field was established by ANSYS software. The distribution law of the pipeline magnetic field and eddy current field were analyzed, and the influence of size and structure parameters of the coil inside the probe were studied. The internal stress detection system of the pipeline was designed, and the static tensile stress measurement experiment was carried out. Simulation and test results showed that the excitation coil with a larger diameter-to-height ratio had a higher measurement sensitivity. The sensitivity of the probe decreased monotonically with the increase of the difference between inner diameter and outer diameter of the detection coil. It increased monotonically with the increase of the equivalent radius of the detection coil. The best measurement results were obtained when the detection coil was located at the center of the two legs of the U-magnetic core. The results showed that the system could identify the pipeline stress concentration area effectively after detection engineering.