Optical Scanning Apparatus for Ropes nondestructive test monitoring system

Nondestructive testing for synthetic fibre ropes is an important step to ensure their safe use as mooring lines for offshore floating platforms. OSCAR is an acronym derived from Optical Scanning Apparatus for Ropes. OSCAR is a new, nondestructive system that has been developed using an optical fibre transducer and a measurement technique known as Brillouin scattering. This is a distributed method and allows changes in the length to be detected along entire length of the optical fibre. It consists of the Brillouin Optical Time Domain Reflectometer (BOTDR) and the optical fibre transducer. The optical transducer is built into the rope in such a way that it elongates with the rope elongation. The transducer's fibres are connected to the BOTDR which detects the resultant elongation in the optical fibres. As the rope wears or is damaged there is both general and local loss of strain bearing synthetic fibre with a corresponding increase in elongation. When the elongation becomes excessive the rope is retired. This paper describes the system and presents the results of the system testing.