Composite Fluid Connector Seal Structure for Thermal Expansion Matching
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Solution Overview
Problem
Conventional connectors for fluid transfer conduits, especially those made of metal, face issues with material wastage, galvanic corrosion, and sealing problems when used with composite materials, and they struggle to maintain a consistent seal due to thermal expansion differences and require complex manufacturing processes.
Innovation Solution
The method involves using continuous fibre reinforcement oriented circumferentially and pre-impregnated with thermoplastic polymer for the seal section, combined with injection moulding for the rest of the connector, which reduces material waste, enhances sealing reliability, and allows for complex shapes while minimizing thermal expansion issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If connectors are machined from a single block of metal, then strength and structural integrity are improved, but material wastage increases significantly
Solution Approach 1:
The invention changes the manufacturing parameter from subtractive machining to additive injection moulding, fundamentally altering how the connector is formed. This allows the connector to be built up layer by layer from molten thermoplastic material, achieving the required strength while using only the necessary amount of material without excessive removal.
Solution Approach 2:
The invention employs composite materials consisting of thermoplastic matrix reinforced with randomly oriented chopped fibres (carbon, glass, or aramid). This composite structure provides the necessary mechanical strength and stiffness to replace solid metal connectors while enabling injection moulding manufacturing, thus reducing material wastage.
2Strength
If connectors are made from metal, then strength is improved, but galvanic corrosion and thermal expansion issues occur when used with composite fluid transfer conduits
Solution Approach 1:
The invention uses homogeneous polymer-based materials for both the connector and the fluid transfer conduit. Both components are made from thermoplastic materials with similar thermal expansion coefficients, eliminating the galvanic corrosion and differential thermal expansion problems that occur when dissimilar materials (metal and composite) are joined.
Solution Approach 2:
The connector uses fibre-reinforced thermoplastic composite materials that provide metal-level strength while maintaining compatibility with composite fluid transfer conduits. The fibre reinforcement (carbon, glass, or aramid) embedded in the thermoplastic matrix delivers the required mechanical properties without the harmful interactions associated with metal-composite interfaces.
3Loss of substance
If injection moulding is used to produce composite connectors, then material waste is reduced, but sealing quality deteriorates due to the required taper
Solution Approach 1:
The invention divides the connector into two distinct manufacturing zones: the hub portion is injection moulded from thermoplastic material, while the sealing surface is separately formed by winding pre-preg continuous fibre reinforcement. This segmentation allows each zone to be optimized for its specific function, with the sealing surface providing the required precision without compromising the efficiency of injection moulding for the main body.
Solution Approach 2:
The invention applies different manufacturing methods and material properties to different locations on the connector. The hub portion uses injection moulding with chopped fibre reinforcement for efficient production, while the sealing surface uses pre-preg continuous fibre winding to achieve the smooth, high-precision finish required for sealing, thus providing local quality optimization.
4Reliability
If continuous fibre reinforcement is applied circumferentially to the seal section, then sealing reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The invention segments the manufacturing process into two straightforward operations: first, the hub portion is injection moulded in a standard injection moulding machine; second, the sealing surface is formed by winding pre-preg continuous fibre reinforcement around the hub. This segmentation keeps each step relatively simple and avoids the need for complex automated fibre placement systems.
Solution Approach 2:
The invention uses pre-preg continuous fibre reinforcement that has already been impregnated with thermoplastic polymer before application. This preliminary impregnation simplifies the manufacturing process by eliminating the need for separate resin injection or consolidation steps, allowing the fibre reinforcement to be directly wound and cured to form the sealing surface.
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 a lightweight, cost-effective connector with improved hoop strength, reduced material usage, and a consistent seal across a wide temperature range, suitable for high-pressure applications like aerospace, by matching the coefficient of thermal expansion of the fluid transfer conduit.
Implementation Method 1
applying continuous fibre reinforcement, oriented at least partially circumferentially and pre-impregnated with a thermoplastic polymer to a tubular mould portion
Implementation Method 2
injecting a thermoplastic polymer into the mould to form a connector with a tubular hub portion and a flange portion
Implementation Method 3
a reduced temperature operating window due to unequal thermal expansion
Data Source
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AI summary
A method of manufacturing a composite connector 2, 124 for a fluid transfer conduit is provided which comprises applying continuous fibre reinforcement 103, oriented at least partially circumferentially and pre-impregnated with a thermoplastic polymer to a tubular mould portion 104 which extends substantially parallel to a central axis C; applying at least one further mould portion 106 to form a complete mould 108 in which the continuous fibre reinforcement 103 is enclosed and injecting a thermoplastic polymer 122 into the mould 108 to form a connector 2, 124 with a tubular hub portion 6, 128 and a flange portion 8, 126 which extends from the hub portion 6, 128 at an angle to the central axis C. The tubular hub portion 6, 128 comprises a tubular seal section 7 with an inner layer 11, 130 and an outer layer 9, 132, wherein the inner layer 11, 130 comprises the continuous fibre reinforcement 15, 103 and the outer layer 9, 132 comprises the injected thermoplastic polymer 122.