Flexible Pipe End Fitting with Widener Elements for Tensile Anchoring

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Solution Overview

Problem

Existing end fittings for flexible tubular pipes, particularly those in deep-sea applications, face challenges in resisting being torn out due to high tensile forces and fatigue, with current solutions either being costly or reducing the mechanical characteristics of steel wires, leading to increased size and cost.

Innovation Solution

The use of widener elements attached to the free ends of tensile armor layers, which are welded and designed to locally widen the cross-section, allowing them to be trapped in a solidified material within an annular chamber, thereby absorbing tensile forces and preventing movement, without compromising the mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If additional immobilization means are used to improve resistance to being torn out, then the anchoring strength is improved, but the device complexity and cost increase

Engineering Contradiction:

Improveresistance to being torn outVSAvoidcomplexity of end fitting structure

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The invention applies local deformation (flattening or crimping) only to the free ends of the armor layer wires where they terminate in the annular chamber, rather than modifying the entire wire structure. This localized treatment provides the necessary anchoring strength at the critical point while keeping the rest of the structure simple and cost-effective.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The immobilization means are pre-formed on the free ends of the armor layer wires before insertion into the annular chamber. This preliminary deformation creates ready-to-anchor structures that simply need to be trapped in the solidified material, eliminating the need for complex installation procedures or additional components.

Inventive Principle:

Principle #10Preliminary action

2Strength

If the annular chamber dimensions are increased to improve anchoring, then the anchoring capacity is improved, but the size and cost of the end fitting increase

Engineering Contradiction:

Improveanchoring capacityVSAvoidsize of end fitting

Core Design Contradiction:

StrengthVSVolume of stationary object

Solution Approach 1:

The invention changes the physical state of the material in the annular chamber from liquid to solid through curing, and modifies the geometry of the wire ends through local deformation. These parameter changes enable effective anchoring within a compact annular chamber volume, avoiding the need for larger dimensions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The end fitting utilizes a composite anchoring system combining mechanically deformed wire ends (flattened or crimped structures) with chemically bonding solidified material (epoxy or similar polymer). This composite approach maximizes anchoring capacity within limited space by combining mechanical interlocking with chemical adhesion.

Inventive Principle:

Principle #40Composite materials

3Strength

If cold deformation is applied to increase tensile strength, then the mechanical strength is improved, but the ductility and temperature sensitivity worsen

Engineering Contradiction:

Improvetensile yield strengthVSAvoidductility and temperature sensitivity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

Cold deformation is applied only locally to the free ends of the armor layer wires rather than to the entire wire length. This localized treatment maintains the high tensile strength of the cold-worked regions while preserving the ductility and temperature resistance of the main wire body, which remains unaffected by the deformation process.

Inventive Principle:

Principle #3Local quality

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

This solution enhances the resistance to being torn out while maintaining the mechanical strength of the steel wires, reducing the size and cost of the end fittings, and ensuring even stress distribution without the risk of cascade breakage.

Implementation Method 1

the anchoring mechanism relies only on the one hand on the adhesion between the wires and the cured polymer

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

on the other hand on the capstan effect associated with the fact that the wires do not extend in a straight line inside the cured polymer

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 3

said widener elements are advantageously welded to said free ends of armor layer

Methodology Applied

Scientific EffectWelding: Welding

Data Source

PatentUS8096589B2High-resistance end fitting for a flexible tubular pipe

Publication Date: 2012.01.17 TECH FRANCE SA

AI summary

An attachment fitting and a method for connection to a tubular duct comprising at least one ply of armors, the armors having a free end respectively defining an outer surface, the attachment fitting comprising a bushing and a sleeve having an attachment part and a connection part with a reception portion, the sleeve being mounted on the duct by spreading the free ends of the armor perpendicularly to the reception portion, the armors comprising a widening device, the bushing being mounted about the connection part and forming an annular chamber for receiving a flow of a mass-curing material for encapsulating the free ends of the armors. The widening device connected to the free outer surface of the free ends of the armors.