Analysis of Elastic Moorings

Development of Seaflex elastic moorings simulation capability in ProteusDS

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Overview

Seaflex AB is the maker of the Seaflex elastic mooring system. The Seaflex elastic mooring system is an engineered mooring system that is custom made for each particular location based on the expected forces and conditions.

The Seaflex elastic mooring system elongates and retracts in an even, smooth movement – keeping the mooring platform (e.g. a marina) stable and in position even during severe weather. The unique construction of the system offers unsurpassed dampening of forces which aids in the longevity of the structures it is anchoring. In-house engineers at Seaflex AB help design the best solution for all requirements.

Background

The Seaflex elastic mooring system is for many applications including marinas, wave attenuators, navigational buoys, residential pontoons/docks, floating helicopter platforms, seaplane terminals, floating fish farms, floating solar energy parks, floating houses, wave energy converters, and many more. Designing these systems requires estimating the effect of current, wind and waves on the mooring.

Numerical modelling of the response of the Seaflex mooring system to various conditions is essential to de-risk the use of the use of Seaflex technology where chain moorings are used or to satisfy insurers or engineers’ desires to predict the exact response of the mooring installation a priori.

  • Project challenges

    The Seaflex elastic mooring technology relies on a viscoelastic rubber hawser with hysteretic axial rigidity characteristics. The load response of the Seaflex units depends on the time history of loading and the elongation state of the hawsers.

    This complex phenomenon, while well understood from a conceptual standpoint, can be difficult to represent numerically. Seaflex and DSA have been working together to accurately model the response of Seaflex mooring technology using the ProteusDS line model nonlinear axial rigidity model.

  • Scope of work
    • Implement the Seaflex elastic mooring system model in ProteusDS.
      Develop a software tool that assists users in setting up Seaflex marina simulations.
    • Validate the correct functioning of the model, including modelling the yellow ByPass safety system and unique loading and unloading phenomena.
    • Provide training on how to use ProteusDS to simulate Seaflex mooring technology.
  • Outcomes

    Successfully implemented, the model and the response of the Seaflex elastic mooring system can now be predicted using the full capabilities of the wind, wave, and current models in ProteusDS. The Seaflex team has the skills and capabilities in-house to model a wide range of applications and has access to support from the DSA team for all of their projects.