The University of Southampton
University of Southampton Institutional Repository

Numerical investigations of the effect of strain softening on the behaviour of embedded mooring chains

Numerical investigations of the effect of strain softening on the behaviour of embedded mooring chains
Numerical investigations of the effect of strain softening on the behaviour of embedded mooring chains
Mooring systems typically consist of an anchor and a mooring line and chain that connect the anchor to the floating infrastructure. When the anchor connection point (the ‘padeye’) is below the seabed surface, the interaction between the chain and the seabed will affect the amount of load transferred to the anchor and the load angle at the padeye. Reliable methods are needed therefore to assess these aspects in order to determine appropriate anchor design.

Available solutions for the interaction between soil and chain generally ignore any reduction in the undrained shear strength of the soil as it is remoulded under the large strains associated with tensioning of the anchor chain. This is an unconservative assumption for anchor design, hence providing motivation for the study presented here. The system behaviour and the interaction of short chain segments with the seabed have been studied using a coupled Eulerian-Lagrangian (CEL) approach. The findings have led to two new design approaches that encapsulate how remoulding of the soil (which affects sliding resistance more than bearing resistance) affects the chain system response. Calculations using these methods captured the modelled chain system response well. Both the global chain analyses and the proposed design approaches suggest that approximately the entire chain load at the seabed surface (the ‘mudline’) is likely to be transferred to the anchor padeye, challenging conventional design practice.
0141-1187
Sun, Chao
16c59dfc-f89f-47dd-96ec-b4734295f1f8
Feng, Xiaowei
33d164d1-5589-41f6-995a-9b17374bdd0c
Bransby, Mark Fraser
2ea4cf12-0f35-4e4f-bc19-f52783aacaa3
Neubecker, Steven R.
1b5a0163-c410-4db0-a353-22bbd4bad3c2
Randolph, Mark F.
75caa33a-e630-4ae8-84cd-758797bf9633
Gourvenec, Susan
6ff91ad8-1a91-42fe-a3f4-1b5d6f5ce0b8
Sun, Chao
16c59dfc-f89f-47dd-96ec-b4734295f1f8
Feng, Xiaowei
33d164d1-5589-41f6-995a-9b17374bdd0c
Bransby, Mark Fraser
2ea4cf12-0f35-4e4f-bc19-f52783aacaa3
Neubecker, Steven R.
1b5a0163-c410-4db0-a353-22bbd4bad3c2
Randolph, Mark F.
75caa33a-e630-4ae8-84cd-758797bf9633
Gourvenec, Susan
6ff91ad8-1a91-42fe-a3f4-1b5d6f5ce0b8

Sun, Chao, Feng, Xiaowei, Bransby, Mark Fraser, Neubecker, Steven R., Randolph, Mark F. and Gourvenec, Susan (2019) Numerical investigations of the effect of strain softening on the behaviour of embedded mooring chains. Applied Ocean Research, 92, [101944]. (doi:10.1016/j.apor.2019.101944).

Record type: Article

Abstract

Mooring systems typically consist of an anchor and a mooring line and chain that connect the anchor to the floating infrastructure. When the anchor connection point (the ‘padeye’) is below the seabed surface, the interaction between the chain and the seabed will affect the amount of load transferred to the anchor and the load angle at the padeye. Reliable methods are needed therefore to assess these aspects in order to determine appropriate anchor design.

Available solutions for the interaction between soil and chain generally ignore any reduction in the undrained shear strength of the soil as it is remoulded under the large strains associated with tensioning of the anchor chain. This is an unconservative assumption for anchor design, hence providing motivation for the study presented here. The system behaviour and the interaction of short chain segments with the seabed have been studied using a coupled Eulerian-Lagrangian (CEL) approach. The findings have led to two new design approaches that encapsulate how remoulding of the soil (which affects sliding resistance more than bearing resistance) affects the chain system response. Calculations using these methods captured the modelled chain system response well. Both the global chain analyses and the proposed design approaches suggest that approximately the entire chain load at the seabed surface (the ‘mudline’) is likely to be transferred to the anchor padeye, challenging conventional design practice.

Text
2019 APOR_Sun et al_strain softening.pdf Accepted manuscript - Accepted Manuscript
Download (966kB)

More information

Accepted/In Press date: 23 September 2019
e-pub ahead of print date: 26 September 2019
Published date: November 2019

Identifiers

Local EPrints ID: 435357
URI: http://eprints.soton.ac.uk/id/eprint/435357
ISSN: 0141-1187
PURE UUID: b2447337-935f-48d7-a472-156e61d1b3e3
ORCID for Susan Gourvenec: ORCID iD orcid.org/0000-0002-2628-7914

Catalogue record

Date deposited: 31 Oct 2019 17:30
Last modified: 28 Apr 2022 05:29

Export record

Altmetrics

Contributors

Author: Chao Sun
Author: Xiaowei Feng
Author: Mark Fraser Bransby
Author: Steven R. Neubecker
Author: Mark F. Randolph
Author: Susan Gourvenec ORCID iD

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×