Expandable Mandrel Assembly for Uniform Composite Pipe Curing

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Solution Overview

Problem

Current composite pipe manufacturing methods face challenges in achieving uniformity and preventing irregularities and voids due to resin shrinkage during curing, which can lead to sticking and surface irregularities in the pipes.

Innovation Solution

The method involves wrapping fibre reinforcement material tightly around a mandrel with a resilient sleeve that expands during curing, using a pressurizing fluid to maintain internal pressure and control temperature, and evacuating the resin before injection to ensure even filling and minimize shrinkage issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If resin is injected into the mould to fill the annulus, then the composite pipe is formed, but resin shrinkage during curing causes voids and surface irregularities

Engineering Contradiction:

Improveuniformity of composite pipeVSAvoidpresence of voids and irregularities

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The resilient sleeve is pre-installed on the mandrel before resin injection to anticipate and counteract the resin shrinkage that occurs during curing. The sleeve's resilient nature allows it to expand and fill voids, preventing surface irregularities before they become defects in the final product.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The mandrel with the resilient sleeve is prepared and positioned in the mould before the resin injection process begins. This preliminary setup ensures that the sleeve is in place to immediately counteract shrinkage as the resin cures, maintaining uniformity throughout the manufacturing process.

Inventive Principle:

Principle #10Preliminary action

2Stability of the object's composition

If the mandrel is made rigid to provide structural support, then stability is improved, but the mandrel cannot expand to compensate for resin shrinkage

Engineering Contradiction:

Improvestructural stability of mandrelVSAvoidability to expand during curing

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The mandrel is divided into two functional segments: a rigid internal support structure that provides structural stability, and a resilient outer sleeve that can expand during curing. This segmentation allows each component to perform its specialized function without compromise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The mandrel combines two different material properties - rigid material for the internal support structure and resilient material for the outer sleeve. This composite construction enables the mandrel to simultaneously maintain structural stability and adaptability during the curing process.

Inventive Principle:

Principle #40Composite materials

3Manufacturing precision

If the resilient sleeve is made expandable to compensate for shrinkage, then uniformity is improved, but the mandrel structure becomes more complex

Engineering Contradiction:

Improvedimensional uniformity of pipeVSAvoidcomplexity of mandrel structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The resilient sleeve acts as a flexible shell that can expand radially to compensate for resin shrinkage. This flexible component is relatively simple in construction, requiring only the resilient material property, rather than complex mechanical expansion mechanisms.

Inventive Principle:

Principle #30Flexible shells and thin films

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 approach results in composite pipes with uniform dimensions and reduced risk of sticking and surface irregularities, allowing for efficient production of pipes with high strength and smooth surfaces.

Implementation Method 1

supplying by a supply means (10) a pressurizing fluid to internally pressurize the sleeve (6) to cause the diametrical expansion into the expanded state thereof

Methodology Applied

Scientific EffectElastic expansion: Elasticity

Implementation Method 2

introducing a thermosetting resin that shrinks upon curing into the closed annulus

Methodology Applied

Scientific EffectThermal shrinkage: Thermal Contraction

Implementation Method 3

arranging a vacuum pump that is configured to evacuate the annulus

Methodology Applied

Scientific EffectVacuum evacuation: Vacuum

Implementation Method 4

the resin permeating the fibre reinforcement material and filling the annulus

Methodology Applied

Scientific EffectPermeation: Permeation

Data Source

PatentUS20240336021A1Assembly and method for manufacturing composite pipes

Publication Date: 2024.10.10 ITREC BV

AI summary

Moulding a composite pipe of fibre reinforcement material and a thermosetting resin that shrinks upon curing includes wrapping fibre reinforcement material about the tubular resilient sleeve of a mandrel in a non-expanded state of the sleeve. The mandrel includes an internal support structure for the sleeve which is reversibly expandable in diameter between the non-expanded state. The sleeve is internally supported by the internal support structure and an expanded state by application of an internal pressure to the sleeve. The mandrel with the fibre reinforcement material wrapped about the sleeve is accommodated in a bore of a mould. Seal members provide a closed annulus that can be evacuated. A thermosetting resin that shrinks upon curing is introduced into the closed annulus. A pressurizing fluid is supplied to the mandrel to internally pressurize the sleeve to cause diametrical expansion into the expanded state thereof whilst curing of the thermosetting resin.