Mooring component having a smooth stress-strain response to high loads
A mooring component comprises a plurality of different deformable elements formed of an elastomeric material. The component has a tensile length L and at least one of the elements has a length L′<L. As the mooring component comprises a plurality of different elastomeric elements, each having its own unique elastic (i.e. reversible) stress-strain response, the overall response of the component is a composite elastic response resulting from a combination of the responses of each of the plurality of elastomeric elements. The mooring component can form part of a mooring system for floating devices and sea-based structures such as renewable energy devices, including wave energy conversion devices, tidal turbines and tidal platforms, fish farms, oil rigs and off-shore wind farms, especially in low scope or high variability environments.
1. A mooring component comprising at least one tensile element and at least one compressive element, both the tensile and compressive elements being configured to undergo strain in response to a tensile stress wherein the at least one tensile element is connected in the mooring component such that the at least one tensile element gives a tensile response providing a tensile force as the at least one tensile element is stretched as the mooring component undergoes extension and, the at least one compressive element is connected in the mooring component such that the at least one compressive element is compressed in response to extension of the mooring component beyond a certain threshold wherein the at least one tensile element and the at least one compressive element are formed of an elastomeric material.
2. A mooring component as claimed in claim 1 , wherein the at least one tensile element and at least one compressive element are configured to respond to the tensile stress in parallel.
3. A mooring component as claimed in claim 1 , wherein a stress-strain response of the mooring component is a composite elastic response resulting from a combination of a response from each of the least one tensile element and the at least one compressive element.
4. A mooring component as claimed in claim 1 , comprising at least one, two, three, four, five, six or more elastomeric tensile elements configured to provide a tensile response to said tensile stress.
5. A mooring component as claimed in claim 1 , comprising at least one, two, three or more elastomeric compressive elements configured to provide a compressive response to said tensile stress.
6. A mooring component as claimed in claim 1 , comprising at least one tensile element having a length L equal to the tensile length of the mooring component and at least one compressive element having a length L′<L.
7. A mooring component as claimed in claim 1 , wherein the at least one compressive element comprises an elastomeric material having a higher elastic modulus than that of one or more said tensile element(s).
8. A mooring component as claimed in claim 1 , wherein the at least one tensile element comprises a plurality of different deformable elastomeric elements which have different lengths and/or thicknesses and/or are formed of different elastomeric materials.
9. A mooring component as claimed in claim 1 , wherein the at least one compressive element comprises a cylindrical corrugated or bellowed member formed of elastomeric material.
10. A mooring system comprising one or more mooring components according to claim 1 , wherein the one or more mooring components are connected, directly or indirectly, between a floating body and a seabed.
11. A method of manufacturing a mooring component for a deep sea mooring system, comprising the steps of:
identifying a body to be moored and a location in which it is to be moored;
determining an expected environmental loading on the body at the location;
determining a stress-strain response required for the mooring component to respond to the expected environmental loading with a desired modification of a plurality of mooring forces on the component; and
forming the mooring component from at least one tensile element and at least one compressive element, both the tensile and compressive elements being configured to undergo strain in response to a tensile stress wherein the at least one tensile element is connected in the mooring component such that the at least one tensile element gives a tensile response providing a tensile force as the at least one tensile element is stretched as the mooring component undergoes extension and, the at least one compressive element is connected in the mooring component such that the at least one compressive element is compressed in response to extension of the mooring component beyond a certain threshold wherein the at least one tensile element and the at least one compressive element are formed of an elastomeric material.
12. The method of claim 11 , wherein the at least one tensile element and the at least one compressive element respond to the tensile stress in parallel.
13. The method of claim 11 , wherein a stress-strain response of the mooring component is a composite elastic response resulting from a combination of a response from each of the least one tensile element and the at least one compressive element.
14. The method of claim 11 , further comprising: providing the at least one tensile element with a length L equal to a tensile length L of the mooring component and providing the at least one compressive element with a length L′ wherein L′<L.
15. The method of claim 11 , further comprising: forming the at least one compressive element with a higher elastic modulus than the at least one tensile element.
16. The method of claim 11 , further comprising: forming the at least one tensile element from a plurality of different deformable elastomeric elements which have different lengths and/or thicknesses and/or are formed of different elastomeric materials.
17. The method of claim 11 , further comprising: forming the at least one compressive element as a cylindrical corrugated or bellowed member formed of elastomeric material.