Transient Force-Magnetic Coupling Simulation Research on Pipeline Stress Concentration

Abstract

The stress concentration of oil and gas pipelines will produce corrosion cracks and axial fatigue cracks under the action of long-term and repeated internal pressure, and will rapidly expand under fluctuating internal pressure, resulting in serious pipeline accidents. In order to effectively detect the stress concentration of oil and gas pipelines, a stress concentration detection technology of unsaturated local magnetization pipeline is proposed. This paper introduces the theoretical basis of local pipeline stress concentration detection, establishes a two-dimensional finite element model of pipeline stress concentration transient force-magnetic coupling, and analyzes the influence of excitation source position, sensor lift-off value, and stress concentration value on the response signal. The simulation results show that the corresponding signal B x of the stress concentration changes more obviously than B y and the signal is regular, Bx has a good two-stage linear positive correlation with the stress concentration value. The above research provides technical support for the development of pipeline on-line stress concentration detection probe.

Prognosis methods of stress corrosion cracking under harsh environmental conditions

“…SCC occurs under tensile mechanical or thermal loading, and it is affected by several mechanical factors that can aggravate the severity of cracking, especially in harsh environmental conditions [ 27 ]. These mechanical factors include applied stress, stress concentration factors, residual stress, strain rate, vibrations, and cyclic loading [ 28 , 29 ]. The presence of stress concentration factors and residual stress can further promote the propagation of stress corrosion cracks by deteriorating the local mechanical properties of materials [ 30 ].…”