Evaluation of rope strand noise in wire ropes inspection using the magnetic flux leakage testing

Abstract

Magnetic flux leakage testing to compensate for the visual inspection in the inspection of the wire ropes has been studied. In recent years, it has become possible to improve the damage detection accuracy by using a device which utilizes the hall effect and magnetoresistance effect due to the development of semiconductor technology. Detection of the small damage also became possible. However, since the noise of measurement data is contained much when inspecting the wire ropes, it is difficult to detect a very small damage. Cause of noise depends on the configuration of the eccentric and the strands and the strands of the rope. Eccentricity of the rope has been demonstrated in previous studies to contribute to the noise. However, the noise due to strands and strands of the ropes is an evaluation of only the magnitude of the magnetic flux density. Thus, discussion of the direction of the magnetic flux is not performed. In this paper, the effect of noise caused by the strand is evaluated by experiment and numerical analysis. Furthermore, we verified whether useful in reducing noise due to strands of the rope by the sensor's angle. Therefore, it was found that there is due to strands of the rope as cause of noise. It showed that it is possible to noise reduction by matching the detected angle of the sensor with twist angle of the strand.

Keywords

• wire rope
• magnetic flux leakage testing
• damage detection
• rope tester
• finite element method
• numerical analysis