Filament-Wound Composite Pipe Structure Against Microcrack Leaks

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Solution Overview

Problem

Thermosetting resin composite pipes are prone to microcracks due to brittleness and exothermic curing, which can lead to leaks and structural failure when conveying fluids at high pressure or temperature.

Innovation Solution

A composite pipe design featuring a hollow cylindrical liner shielded by a thermoset outer layer of resin-impregnated filaments, which are wound about the liner and flange end attachments to enhance structural strength and prevent microcrack propagation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thermoset resin is used to construct high strength composite pipe, then the pipe achieves great strength and high volume fraction composites, but the pipe becomes prone to microcracks due to brittleness and exothermic curing

Engineering Contradiction:

Improvecomposite pipe strengthVSAvoidmicrocrack resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent uses a hybrid composite structure combining thermoset resin with thermoplastic polymer matrix and elastomeric material. The thermoplastic matrix (HDPE, LDPE, or LLDPE) combined with elastomeric particles (EPDM, NBR, or CR) creates a more ductile composite material that maintains strength while reducing brittleness and microcrack formation during exothermic curing

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition parameters of the resin matrix by incorporating thermoplastic polymers and elastomeric materials in specific ratios (30-70 wt% thermoplastic, 5-40 wt% elastomeric). This parameter change transforms the purely brittle thermoset system into a more resilient composite that can withstand thermal and mechanical stresses without microcracking

Inventive Principle:

Principle #35Parameter changes

2Strength

If thermoset resin is used for high performance composite pipe, then structural integrity is enhanced, but the pipe is susceptible to microcracks under high pressure or temperature conditions

Engineering Contradiction:

Improvestructural integrityVSAvoidmicrocrack susceptibility under pressure and temperature

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the thermal and mechanical parameters of the composite by incorporating thermoplastic polymers with high melting points and elastomeric materials with low glass transition temperatures. This creates a composite that maintains structural integrity at high temperatures while remaining flexible and crack-resistant under pressure loading conditions

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies different material properties to different phases of the composite: the thermoset resin provides localized strength and rigidity, while the thermoplastic matrix provides overall structural integrity and ductility, and the elastomeric particles provide localized flexibility and crack propagation resistance under stress concentrations

Inventive Principle:

Principle #3Local quality

3Productivity

If traditional filament winding process is used with thermoset resin, then high volume fraction composites can be manufactured, but the exothermic curing process causes microcracks in the resin matrix

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidresin matrix integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent maintains the efficient filament winding process while modifying the composite material composition to include thermoplastic and elastomeric components. This allows continuous production with high volume fraction while the modified material composition prevents microcrack formation during the exothermic curing phase

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The thermoplastic polymer matrix acts as an intermediary between the thermoset resin and the external environment, absorbing and distributing thermal stresses during curing. The elastomeric particles serve as stress distributors that prevent crack initiation and propagation, allowing the exothermic curing process to proceed without compromising matrix integrity

Inventive Principle:

Principle #24Intermediary (Mediator)

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 design effectively reduces the risk of microcrack-induced failure by distributing stress and providing additional structural integrity, while allowing for a simple and cost-effective manufacturing process.

Implementation Method 1

The design effectively reduces the risk of microcrack-induced failure by distributing stress and providing additional structural integrity

Methodology Applied

Scientific EffectStress distribution:

Implementation Method 2

which are wound about the liner and flange end attachments to enhance structural strength and prevent microcrack propagation

Methodology Applied

Scientific EffectCrack propagation resistance:

Data Source

PatentUS20250146600A1Composite pipe

Publication Date: 2025.05.08 SAUDI ARABIAN OIL CO

AI summary

A composite pipe includes a hollow, cylindrical liner, a flange end attachment comprising a flange and a cylindrical main body with a bore extending therethrough within which an end portion of the liner is disposed, and a thermoset outer layer comprising resin-impregnated filaments. The filaments of the thermoset outer layer are in contact with and wound about at least a portion of an external surface of the liner and at least a portion of an external surface of the cylindrical main body of the flange end attachment.