Friction Clamping for Subsea Tubular Connections
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Solution Overview
Problem
Existing subsea tubular connections, such as pile to sleeve connections, face issues with high bending moments and cyclic fatigue due to shear transfer of load, requiring heavy pins that are susceptible to failure.
Innovation Solution
A tubular clamping arrangement using a pressure inducing member and a support collar to apply clamping pressure, maintaining the circularity of the inner tube and preventing jamming, with load transfer via frictional resistance and deformation, minimizing bending stresses and enhancing load transfer capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If shear transfer from pistons is used to connect tubular members, then load transfer is achieved, but high bending moments are induced causing cyclic fatigue and potential failure
Solution Approach 1:
The patent replaces the piston-based shear transfer mechanism with a friction-based clamping system. Instead of using pins and pistons that create bending moments, the invention uses a clamping member that applies radial pressure to create frictional resistance, thereby transferring load without inducing cyclic bending stresses in the connection components.
Solution Approach 2:
The invention changes the load transfer mechanism from direct shear transfer through pins to friction-based transfer through controlled normal pressure. By adjusting the clamping force and friction coefficient, the system achieves reliable load transfer while eliminating the harmful bending moments that cause fatigue.
2Strength
If heavy pins are used to resist bending moments, then connection strength is maintained, but device complexity and susceptibility to fatigue increase
Solution Approach 1:
The patent eliminates heavy pins and complex shear transfer mechanisms by substituting them with a simpler friction-based clamping system. The clamping member applies radial pressure to create frictional resistance, which transfers load without requiring complex mechanical components susceptible to fatigue.
3Strength
If clamping pressure is applied to force tubes together, then load transfer capacity is enhanced, but risk of crushing the tubes increases
Solution Approach 1:
The invention optimizes the clamping pressure parameters to achieve sufficient frictional resistance for load transfer while remaining below the crushing threshold of the tubular members. The system uses controlled normal pressure that is carefully calibrated to generate adequate friction without causing material failure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces bending stresses and enhances load transfer capacity, allowing for secure connection and disconnection of tubular members while minimizing the risk of cyclic fatigue and failure, using frictional resistance and controlled deformation to maintain the connection without causing crushing.
Implementation Method 1
load transfer via frictional resistance and deformation
Implementation Method 2
maintaining the circularity of the inner tube so that the inner tube when unclamped may be withdrawn from the outer tube
Data Source
AI summary
An arrangement for fixing two concentric tubes (1, 2) together by means of one or more pressure inducing members, preferably each formed as a pad (6); the member acts to press the tubes together; a support (3), preferably formed as a collar fixed inside the outer tube (1), is provided opposite the or each location of the or each member. The support is designed to maintain the circularity of the inner tube so that it can be readily withdrawn from the outer tube without jamming. This is useful for off-shore installations.