Author – Dr Tessa Gordelier

A new paper has been published by #ExeterMarine academics Prof. Lars Johanning, Dr Tessa Gordelier and Dr Philipp Thies in collaboration with the French research institute IFREMER (@Ifremer_en).

The mooring systems were put through their paces at the University of Exeter’s DMaC facility

Assessing the performance durability of elastomeric moorings: Assembly investigations enhanced by sub-component tests”  investigating novel mooring tether performance for offshore renewable applications.

The growing marine renewable energy sector is placing new demands on mooring systems; not only are they required to hold devices on station they must also provide the compliance required to harvest energy from the marine environment.  In response to this, several innovative mooring tethers have been proposed, with increased compliance and a degree of customisation of the stiffness profile.  Many of these novel systems utilise materials in a unique application within the challenging marine environment and their long term durability remains to be proven.

The novel mooring system underwent 6 months of sea trials on a mooring limb of the South West Mooring Test Facility

In response to this challenge, the work presented in this paper summarises a multifaceted investigation into the durability of a novel mooring tether with an elastomeric core.  Tether assembly testing is conducted before and after a 6 month sea deployment in addition to detailed laboratory investigations.  At a sub-component level, to represent the operational demands of the tether on the elastomer core, detailed material investigations review the effect of both marine exposure and repeated compression loading on key material properties. This work is the first of this type to be published and will be of interest to anyone utilising this material in other relevant applications.

Overall the results indicate an increase in both material and tether stiffness profile with use; this will affect both system dynamics and mooring loads.  If we are to realise the benefits of these novel mooring systems, this characterisation is crucial to ensure reliable and effective integration into offshore engineering projects.

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