Research on Quantitative Detection of Magnetic Signals of Wire Rope Defects Based on Magneto-Mechanical Coupling Effect under Weak Magnetic Excitation

Steel wire ropes are widely used in industries such as mine hoisting, construction, and bridge construction. Structural failure during long-term, high-frequency operation can cause significant economic losses and even threaten human safety. Magnetic flux leakage testing (MFL) is a nondestructive testing technique that can detect defects in steel wire ropes. This study examined arc-shaped wear defects in steel wire ropes. Based on the magneto-mechanical coupling effect, a magneto-mechanical coupling parameter model was established under a constant weak magnetic field (200 A/m). The interaction between stress and magnetic permeability in the elastic phase was analyzed. Finite element analysis (FEA) was used to quantitatively analyze the damage magnetic signal, verifying a strong correlation between the damage magnetic signal and defect depth and tensile force. Due to the complex structure of the wire rope, the magnetic signal morphology of the arc-shaped wear defect region is similar to that of the non-defect region. The gradient values of the collected axial and radial magnetic signals were calculated. Under a weak magnetic field, the gradient eigenvalues increased approximately threefold compared to those under a geomagnetic field. The gradient eigenvalues increased linearly with both defect depth and tensile force. Curve fitting effectively determined the defect location and damage severity. The research results provide theoretical basis and method support for nondestructive testing and quantitative evaluation of steel wire ropes under weak magnetic excitation.