Stress detection experiment and simulation of oil and gas pipelines under geomagnetism

In this paper, the study focuses on the evolution mechanism underlying stress concentration formation in oil and gas transmission pipelines when subjected to various factors such as medium internal pressure and material property deterioration. It seeks to explore the relationship between the law of existing magnetism and stress changes induced by geomagnetism within these pipelines, as well as to develop a stress detection methodology. Theoretical models are compared and analyzed for the magnetic behavior under both unidirectional and complex stress conditions within oil and gas pipelines. Simulations are performed to assess the magnetic signal distribution across the pipeline wall, yielding insights into the behavior concerning the change law of magnetic flux signals under complex stress. In addition, a test platform is constructed to facilitate stress and magnetic flux testing on a model of an X80 pipeline exhibiting varying degrees of damage. These experiments aim to validate the theoretical stress detection model based on observed magnetic field changes. The results demonstrate a positive correlation between the existing magnetic flux signal and the applied stress, with a roughly linear relationship. This research establishes the feasibility of utilizing the existing magnetic flux signal to detect stress distribution within oil and gas pipelines.