Abstract

Bio-colonisation is shown to affect the ageing of materials and the behaviour of offshore structures. It was recognized in the 70’s that bio-colonisation might change the loading due to hydrodynamic and mass effects. Mooring systems and umbilicals belong to a family of components sensitive to biocolonisation, which is therefore impacting their lifetime. However, marine growth is a stochastic process with time and space which is hard to predict without previous knowledge and environmental parameters. Our purpose is then to quantify, when it is possible, parameters of bio-colonisation all along the lifetime in order to reduce uncertainties on long term fatigue damages.

The poster is presenting a methodology which consists of updating an ‘a priori’ spatial model for biocolonisation by combining tension measurements in mooring lines with environmental parameters measurements during a Qualifying Sea State and solving an inverse problem. Thanks to this mechanical engineering monitoring of marine growth, temporal models are made more accurate and through time-dependent reliability analysis, mooring lines maintenance can be improved.

 

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The MUSCAS project was carried out within the framework of the WEAMEC, and with funding from Pays de la Loire Region, by Nantes University.