Experimental study of vibration effect on self-magnetic flux leakage measurement of corroded steel strands

Abstract

The self-magnetic flux leakage (SMFL) method has excellent potential in corrosion measurement research of bridge stay cables and suspenders. However, the vibration effect in the cable’s SMFL measurement is unclear and short of the systematic experimental analysis. Based on the magnetic field superposition principle, this study interpreted the vibration effect on steel cable structure magnetic field. The effect was innovatively summarized by the magnetic field increment resulting from the measuring displacement (ΔBDis) and the defect deformation (ΔBDef). Then, the SMFL measurement experiment of the corroded steel strands during the vibration was carried out. The magnetic field distribution law and the influence of the corrosion loss ratio were also analyzed. The results show that ΔBDis presents a “zero value” distribution law via the statistical histogram. The increment of the magnetic field under vibration mainly depends on ΔBDef, which positively correlates with the structure’s corrosion degree and deformation curvature. An excellent linear correlation between the comprehensive characteristic parameter γsum and the corrosion ratio is obtained. So, the quantitative characterization analysis method under vibration was proposed, and γsum can weaken the vibration effect on the magnetic characteristics of cable structure.