The use of the alternating current field measurement technique for mechanised and semi-automated inspection

摘要

The Alternating Current Field Measurement (ACFM) technique was originally developed to be deployed by divers for the inspection of subsea offshore structures. The main application was the detection and sizing of surface-breaking fatigue cracks. A portable topside unit was also produced for manual use and has successfully been used in the inspection of petrochemical, process, pressurised systems and power generation plant. With the further development of ACFM arrays, the ACFM technique has also been used when mechanised and semi-automated techniques have been required for particular. applications. The ACFM technique has now been applied to the remote inspection of underwater structures using robotic manipulators, the inspection of piping as part of the NASA space programme, corrosion detection in underground storage tanks, the detection of cracks in internal and external threads and for the mechanised inspection of circumferential welds.