Flexible Pipe Bend Stiffener Tapered Gap for Contact Pressure Relief
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Solution Overview
Problem
Conventional bend stiffener designs for flexible pipes often result in contact pressure concentration between the pipe and the stiffener, leading to fatigue failure and increased material costs due to the need for thicker, stronger materials to manage extreme depths and pressures.
Innovation Solution
A tapered gap between the inner surface of the bending guide member and the outer surface of the flexible pipe is introduced, which narrows towards the unconstrained end of the bending guide member, increasing the effective contact area and distributing contact pressure, thereby reducing concentration and extending the pipe's fatigue life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional bend stiffener with uniform gap is used, then the structure is simple and easy to manufacture, but contact pressure concentration occurs between the pipe and stiffener leading to fatigue failure
Solution Approach 1:
The gap between the bend stiffener and flexible pipe is made non-uniform with a tapered profile that varies along the length of the stiffener. The gap width transitions from a first value at the constrained end to a second value at the unconstrained end, creating locally optimized contact pressure distribution different from the conventional uniform gap design.
Solution Approach 2:
The geometric parameter of the gap width is changed along the length of the bend stiffener, transitioning from a constant dimension to a variable dimension. This parameter variation optimizes the contact pressure distribution between the stiffener and pipe, reducing concentration effects while maintaining structural integrity.
2Strength
If thicker and stronger materials are used in armour layers, then the strength and load response of the pipe improve, but the weight of the flexible pipe increases
Solution Approach 1:
The bend stiffener is designed to extract and concentrate the bending loads at the constrained end, allowing the armour layers to be optimized for their primary function without excessive thickness. The stiffener assumes the mechanical burden of bending resistance, enabling lighter armour layer construction while maintaining overall pipe strength.
Data Source
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AI summary
Apparatus and a method are disclosed for limiting contact pressure between a flexible pipe and a bending guide member. The apparatus includes a bending guide member extending over a covered region of a flexible pipe in which the flexible pipe can bend wherein a gap between an inner surface of the bending guide member and an outer surface on the flexible pipe in at least a portion of the covered region is tapered and narrows towards an unconstrained end of the bending guide member.