Finite Element Simulation and Test of Metal Magnetic Memory Detection of Wire Rope Under Weak Magnetic Field

To study the influence of weak magnetic field excitation on the magnetic memory signal of the wire rope surface, we use ANSYS Workbench finite element simulation software to perform static analysis on the simplified wire rope model with rectangular defects. Through the force-magnetic coupling equation calculation, the magnetic permeability obtained is imported into the magnetostatic analysis to obtain the coupling field result. The change rule of magnetic memory signal of defective wire rope under weak magnetic field and geomagnetic field is analyzed. The results show that the weak magnetic field excitation has a great influence on the change of the metal magnetic memory (MMM) signal. With the continuous increase of the stress, the peak-to-peak value of the normal component H-p(y) and the amplitude of the tangential component H-p(x) under the weak magnetic field increase significantly compared with the geomagnetic field. In the actual test, a set of weak magnetic excitation device was designed. By applying different pulling forces to the wire rope, the normal component H-p(y) of the magnetic memory signal on the surface of the wire rope under the geomagnetic field and the weak magnetic field was detected, and the gradient K was calculated. Comparing the test results with the simulation results, the effectiveness of the weak magnetic excitation on the magnetic memory signal of the wire rope is proved. The research results are of great significance for the early damage detection of wire ropes.