Increasing Detection Resolution of Wire Rope Metallic Cross-Sectional Area Damage Based on Magnetic Aggregation Structure

Wire rope is a chain structure, and the strength of the weakest link is the strength of the entire wire rope. The axial resolution of loss of metallic cross-sectional area (LMA) detection using the induction coil is related to the length of the detection probe, which is usually greater than or equal to the length of the probe. Improving the axial resolution is an important technical indicator of the LMA. In this article, through theoretical analysis based on the principle of magnetic aggregation and 3-D transient magnetic field simulation, a particular kind of magnetic aggregation structure used for winding coil is proposed and optimized. Simulation and experimental results show that for wire rope LMA detection adding the proposed magnetic aggregation structure, the defect signals' signal-to-noise ratio (SNR) is improved and the axial resolution of the LMA is increased to 20 mm. At the same time, the cross-sectional area loss can be quantitatively evaluated by the magnetic flux peak-to-peak value. The difference between the maximum and minimum values of the derivative of the magnetic flux signal can be used to evaluate the defect length.