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Effect of ice floe on the strength, stability and fatigue of hybrid flexible risers in Artic sea. [Dataset]


D. Korotygin
Data Collector

S.K. Nammi
Data Collector


The harsh and extreme conditions in the Arctic region pose new challenges for the technologies and standards established for traditional open water fields, as they may not be suitable for developments in ice-covered waters. Due to the unique challenges posed by the harsh and extreme environment of the Arctic regions, standardisation organisations such as ISO have developed guidelines for the design and construction of offshore structures in ice-covered waters. However, there are currently no specific guidelines for the design and construction of hybrid flexible riser systems containing a carbon fibre-reinforced polymer layer in ice-prone waters. This is considered a necessary development as more major operators are exploring deeper Arctic fields. In deep-water arctic seas, the use of a lightweight hybrid riser is important to alleviate the problem of high effective tension at the hang-off point. A flexible riser with a Carbon Fibre Reinforced Polymer (CFRP) pressure armour layer is designed to reduce the weight of the riser per metre of length. The materials and dimensions of each layer used in such a hybrid flexible riser have not been widely published due to the limited availability of operational data. The hybrid riser system, incorporating the CFRP composite layer serving as a pressure armour, is instrumental in the conveyance of fluids from the subsea manifold to the vessel located in a deep-water setup.


KOROTYGIN, D., NAMMI, S.K. and PANCHOLI, K. 2023. Effect of ice floe on the strength, stability and fatigue of hybrid flexible risers in Arctic sea. [Dataset]. Journal of composites science [online], 7(6), article 212. Available from:

Acceptance Date May 12, 2023
Online Publication Date May 23, 2023
Publication Date Jun 30, 2023
Deposit Date Jun 12, 2023
Publicly Available Date Jun 12, 2023
Publisher MDPI
Keywords Flexible risers; Carbon fibre reinforced polymer (CFRP); OrcaFlex; Floating production unit (FPU)
Public URL
Publisher URL
Related Public URLs (Journal article)
Type of Data Supplementary tables and results (PDF)
Collection Date Mar 7, 2023
Collection Method The static and dynamic finite element analysis methodology was used to predict the effect of ice floes on the hybrid flexible riser as well as the composite layer within it. Firstly, the static and dynamic global analysis was performed on the entire flexible riser length (approx. 828 m) installed under the sea using OrcaFlex®. Different configurations of flexible risers were analysed in OrcaFlex®, and all stresses were minimised. All results, such as bending moment and effective tension, were extracted from global models of the entire line of flexible risers and the most conservative values of all loads applied on the 1 m-long section of the CFRP (Figure 2b) pressure armour model for local static analysis. This all allowed us to analyse the effect on the CFRP pressure armour of the hybrid flexible riser in a worst-case loading scenario. The composite layer of the hybrid riser was analysed using the Ansys ACP package, which is integrated with a mechanical analysis package. This allowed us to model pre- and post-analyses of the layered/laminate composite modelling. First, the global static and dynamic analysis methodology is presented in the sections below. Subsequently, the local FEA static analysis methodology of the 1 m-section composite layer bonded with a PA-12 polymer inner layer is presented in the analysis. The full methods and results are available in section 2 and 3 of the published article, available from


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