Cables used in mining operations are exposed to high levels of stress and their functional reliability relies on regular monitoring. A new robot has been developed that recognizes fissures before they pose a danger. The robot climbs up the wire cable slowly in a caterpillar-like motion and scans the steel surface and detects whether it has any defects. Researchers at the Fraunhofer Institute for Nondestructive Testing IZFP have named the system FluxCrawler.
The FluxCrawler can be used to monitor the quality of stay cables and wire ropes on a regular basis for tension-induced strain, wear, and corrosion that affect these steel cables. The robot conducts a magnetic flux leakage test which identifies tiny fissures in the cable surface and also recognizes deeper cracks. The process exposes the cable to a magnetic field that is disrupted in the event of a defect. A measurable leakage field is created wherever defects are located. Jochen Kurz, Engineer and Department Head at IZFP said “If such micro-fissures are not discovered in time, the steel can break. This is why material checks are absolutely vital to avoid deadly consequences or even catastrophes”
FluxCrawler can be applied regardless of the cable’s diameter by scanning cylinder shaped surfaces by revolving around the cables and as a result, there is no need to clasp the cable. A permanent magnet prevents slipping and holds FluxCrawler to the cable. At the same time, it generates the magnetization required to make measurements. The battery-operated platform is controlled with a computer via Bluetooth, sending an image of the magnetic field on the cable’s entire surface to the computer, highlighting the areas needing attention.
Flux Crawler developed from the FilameNDT project in cooperation with the French Carnot Institute VITRES-IFFSTAR and are looking to further develop magnetic leakage testing as well as other non-destructive testing methods. The FluxCrawler cannot be used in all situations, such as where the cable is anchored and in such a circumstance other non-destructive testing methods can be used such as EMAT.