Cross-Sectional Loss Quantification for Main Cable NDE Based on the B-H Loop Measurement Using a Total Flux Sensor

Abstract

In the real world, the main cables of suspension bridges are commonly inspected by conducting a periodic visual inspection of the exterior cover of the cable. Although there is a need to conduct a nondestructive evaluation (NDE) of the damage of the main cable, a suitable NDE technique has not yet been developed due to the large diameter and low accessibility of the cable. This study investigates a magnetic sensing cross-sectional loss quantification method that can detect internal and external damage to the main cables. This main cable NDE method applies an extremely low-frequency alternating current (ELF-AC) magnetization method and search coil sensor-based total flux measurement. A total flux sensor head consists of a magnetization yoke and a search coil sensor. To magnetize the main cable, a magnetic field was generated by applying a triangular ELF-AC voltage to the electromagnet yoke. The sensing part measures the magnetic flux that passes through the search coil, and the B-H loop was then obtained using the relationship between the ELF-AC voltage that has been input and the total flux that was measured. Also, the cross-sectional loss can be quantified using a variation of magnetic features from the B-H loop. To verify the feasibility of using the proposed NDE technique, a series of experiments were performed using a main cable specimen with a gradual increase in the cross-sectional loss. Finally, the relationship between the cross-sectional loss and extracted magnetic feature was determined and used to quantify the cross-sectional loss via the proposed method.

On the power and efficiency of Ni2MnGa magnetic shape memory alloy power harvesters

“…where N is the number of turns of the pick-up coil, ∆Φ B is the change in magnetic flux, A is the constant cross-sectional area of the coil, ∆B max is the maximum change in magnetic flux density over the time increment ∆t [30][31][32].…”

Damage detection of cables in cable-stayed bridges using vibration data measured from climbing robot

“…This study concluded that when the cable is in a biased pulse magnetization state, the quantitative evaluation of both the surface and internal flaws can be accessed through measuring the surface magnetic flux leakage and main-flux variation in the cable. Kim et al (2019) presented a method using the total flux sensor for cross-sectional loss quantification for main cables of suspension bridges. In this study, the relationship between the cross-sectional loss and extracted magnetic feature was established and used to quantify the cross-sectional loss.…”

Measurement of Cable Force through a Fiber Bragg Grating-Type Thin Rod Vibration Sensor and Its Application

“…Following a bridge’s abandonment, magnetic flux can be used to detect bridge cable defects [ 10 ] because of its good performance in detecting defects in steel wire ropes. In a study by Kim et al [ 11 , 12 , 13 ], magnetic flux leakage (MFL) was used to diagnose fracture, corrosion, and compression damage to cables. In addition, a multi-stage pattern recognition method that can detect the internal and external damage of the main cable and combine artificial neural network (ANN) has been investigated.…”