Acoustic Emission sensing for detecting damage on the surface of wire rope

Wire ropes are widely used in industrial machinery, such as elevators, and it is important not to overlook wire breaks on maintenance. As for elevator wire ropes, legal inspections are required to be conducted by qualified inspectors to visually check the condition, and the use of digital technology as represented by Internet of Things (IoT) is desired for streamline management. In elevator maintenance, magnetic inspection device as a non-contact rope tester is used to inspect wire ropes, where the condition of the rope is determined by the amount of magnetic leakage. However, since the rope tester scans the rope surface one side at a time, there is a risk of missing a broken strand depending on the scanning timing, considering the rotation of the rope. Therefore, there is a need for a technology that can scan the entire circumference of the rope at the same time. This study proposes a contact-type damage detection system using an Acoustic Emission (AE) technology to detect damage on the wire rope surface. AE is observed as a wave with a high frequency component. We have developed a probe that make contacts along the circumference of the wire rope. When the probe approaches the damaged part of the rope, it is deformed by being caught in the damaged area. In the process of returning to the original position, AE is emitted from the probe to be detected as damage. This system was implemented in the actual elevator. We report on the results of detecting three sample damage points scattered on the surface of a wire rope.