m-pipe® end fitting animation
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m-pipe® end fitting design
Magma has an ‘oil field’ design approach to termination of m-pipe®, to enable the transition from composite pipe to steel pipe or to a steel fitting such as standard flange, hub or threaded connector.
The Magma end fitting is built onto the end of the pipe using the same automated manufacturing methods and materials as the core pipe, with a thickened pipe wall that is first machined to tapered profile, and then interfaced with a steel collar and interface hub. The end fitting assembly is heavily preloaded to produce an efficient and reliable structural load path.
A preloaded AX type gasket is used between the metallic hub and pipe build-up, seated in a PEEK seal pocket on one side and an Inconel 625 pocket on the metallic side. This arrangement also allows m-pipe® to be terminated with a conventional or custom flange, hub or threaded connections to suit the specific application.
The m-pipe® end fitting assembly provides reliable structural performance and sealability. The end fitting can be located directly in the product load path, designed to accommodate extreme and fatigue loading in axial and bending orientations.
This design approach allows end fittings to be supplied with integral taper joints, to allow efficient structural transition from standard pipe walls in the riser dynamic section to a point of fixity, like an interface with a subsea wellhead or vessel porch.
m-pipe® end fitting testing
Development of the m-pipe® end fitting has included optimisation using FEA techniques.
The finished design has been subjected to an extensive qualification process including pressure testing, axial load testing, bending, high cycle fatigue and low cycle fatigue.
Long term pressure testing and thermal testing have also formed part of the test programme.
End fitting testing
Tech paper – Development and qualification of end fittings for composite riser pipe
Whilst much interest is often focused on the composite pipe body it is often forgotten that a reliable end fitting is a prerequisite of a successful composite pipe application, and that the design challenge of the end fitting is even more challenging than the pipe.
This Magma technical paper, originally delivered at OTC, covers the end fitting arrangement for a composite pipe manufactured from carbon fibre and PEEK polymer. The paper describes the design approach and testing and qualification programme employed for the end fitting, to demonstrate reliable application in a critical and structurally demanding application such as for a deep water dynamic riser.
The Magma technical paper summarises historical riser design approaches and design alternatives and explains the reason for selecting the proposed arrangement. The paper also covers the design process used to develop the end fitting design and to predict its structural response, including a discussion of manufacturing issues and detail of the test programme conducted to prove the end fitting performance.