Synthetic fiber ropes constructed of polyester are providing an important new technology for mooring deep-water drilling and production platforms. Considerable effort is being directed toward advancing and qualifying this enabling and cost-effective technology. To date, synthetic fiber mooring ropes have been successfully deployed in Brazil and they have seen limited service in the Gulf of Mexico. Synthetic fiber mooring ropes have high strength-to-weight ratios and possess adequate stiffness, but they are much more susceptible to damage than their steel counterparts. Future safe deployment of synthetic fiber mooring ropes would be significantly enhanced if a reliable technique were available to monitor the performance of the ropes in service and thus provide an early warning of the loss of structural integrity. Test data in the open literature indicates that the strain in the rope at failure is essentially a constant independent of load path or history. Measurement of the accumulated strain in the rope should thus provide a reliable benchmark with which to estimate the remaining life and establish criteria for rope recertification or retirement. This paper discusses the results of research and development activities aimed at developing a reliable, robust method for monitoring strain in braided and twisted strand Synthetic Fiber Mooring Ropes [1]. The strain transducer is a polymeric optical fiber, integrated into the mooring rope and interrogated with Optical Time-Domain Reflectometry (OTDR) to measure changes in its length as the optical fiber and rope are stressed. The method provides a direct measurement of large axial strains. Strains measured in polymeric optical fibers exhibit good one-to-one correlation with applied strains within the test range studied (10% or less, typically). The integrated polymeric optical fiber has been shown to withstand large numbers of repeated cycles to high strains without failure and to accurately track the hysteresis exhibited by polyester rope. Results are reported for tests conducted with polymeric optical fibers integrated into typical mooring rope elements.
Theoretical Investigation of Oxazine 170 Perchlorate Doped Polymeric Optical Fiber Amplifier
