Research on stress detection technology of long‐distance pipeline applying non‐magnetic saturation

Abstract

In order to study the stress detection method on long-distance oil and gas pipeline, the distribution characteristics of the surface remanence signals in the stress concentration regions must be known. They were studied by using the magnetic domain model in the non-magnetic saturation state. The finite element method was used herein with the aim to analyse the static and mechanical characteristics of a ferromagnetic specimen. The variation law of remanence signal in stress concentration regions was simulated. The results show that a residue signal in the stress concentration region exists. In addition, a one-to-one correspondence in the non-magnetic saturation environment is evident. In the case of magnetic saturation, the remanence signal of the stress concentration region is covered and the signal cannot be recognised.

Application of Impact Imaging Method on Nondestructive Detection of Void Defects in Sandwich-Structured Immersed Tunnel

“…erefore, after the pouring is completed, the casting quality of SSIT must be tested, the void defect area should be found in time, and grouting should be carried out to reinforce it before sinking. However, owing to the presence of the steel shell, various electromagnetic wave-based detection methods cannot be applied [12][13][14], such as the magnetic method, which has wide application in long-distance pipeline inspection [15][16][17]. At present, the detections in SSIT structure only rely on the elastic wave and radiation detection methods such as the ultrasonic method, impact acoustic method, the infrared method [18,19], and the neutron method.…”

Research on internal detection technology for axial crack of long-distance oil and gas pipeline based on micromagnetic method

“…11,12 The micromagnetic detection technology has good application potential in the field of axial crack internal detection technology for long-distance oil and gas pipeline because of no excitation requirement, rapid signal recognition speed, sensitivity to microcrack defect, and support for non-contact, on-line, continuous detection. [13][14][15][16][17] In order to study the identification method and influencing factors of micromagnetic signal of pipeline axial crack, the numerical model of axial crack is established based on the magnetic charge theory. The characteristics and propagation of micromagnetic signal influenced by the size and direction of crack are studied, and the X70 pipeline compression test is combined to verify the correctness of theoretical analysis, which provides a theoretical basis for the scientific and reliability of micromagnetic detection for pipeline axial crack.…”

“…11,12 The micromagnetic detection technology has good application potential in the field of axial crack internal detection technology for long-distance oil and gas pipeline because of no excitation requirement, rapid signal recognition speed, sensitivity to microcrack defect, and support for non-contact, on-line, continuous detection. 13–17…”