Thermoplastic Composite Pipe Structure for Impermeable Bending
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Solution Overview
Problem
Current fibre-reinforced polymer matrix composite pipes lack the structural strength and fluid impermeability to replace metal pipes, especially when subjected to high pressures and require shaping on multi-axis pipe-bending machines without becoming porous.
Innovation Solution
A method involving a temporary mandrel, thermoplastic tapes, co-mingled thermoplastic filaments and reinforcing fibres, and a heat-shrinkable layer to form a self-supporting, fluid-impermeable composite pipe that can be bent on a modified multi-axis pipe-bending machine, using novel precursor tapes and tows to create a thermoplastic rich region adjacent the bore.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If fibre-reinforced polymer matrix composite pipes are made to be lightweight and rigid, then weight reduction is achieved, but fluid impermeability and structural strength are insufficient
Solution Approach 1:
The patent employs a composite structure consisting of a thermoplastic matrix composite material reinforced with fibrous reinforcement (such as carbon fibres, glass fibres, or aramid fibres). This composite material combines the lightweight advantage of polymers with the strength and stiffness of fibres, while the thermoplastic matrix ensures fluid impermeability. The composite structure achieves both weight reduction and maintained reliability through the synergistic combination of different materials.
2Strength
If fibre-reinforced composite pipes are made with sufficient structural strength to replace metal pipes, then interchangeability with metal pipes is achieved, but the pipes become porous when bent on multi-axis pipe-bending machines
Solution Approach 1:
The patent utilizes the temperature-dependent properties of thermoplastic materials. During the bending process, the thermoplastic matrix is heated above its glass transition or melting temperature, making it soft and pliable, allowing the pipe to be bent without damaging the fibrous reinforcement structure. After bending, the material is cooled to restore its rigid, fluid-impermeable state. This parameter change (temperature) enables manufacturing flexibility while maintaining structural integrity and fluid impermeability.
Solution Approach 2:
The thermoplastic matrix acts as an intermediary between the fibrous reinforcement and the external environment. It binds the fibres together to form a structurally sound composite, while its ability to soften and harden with temperature changes allows the pipe to undergo bending operations without becoming porous. The matrix protects the fibre structure during manufacturing operations while maintaining the composite's strength.
3Ease of manufacture
If conventional circular braided fabrics are used without internal support, then manufacturing simplicity is maintained, but the pipes lack self-supporting structural strength
Solution Approach 1:
The patent employs a mandrel (internal support structure) around which the circular braided fabric is formed. The mandrel provides temporary structural support during the braiding and forming processes. After the composite pipe structure is established and cured, the mandrel is removed, leaving a self-supporting hollow pipe structure. This nested approach allows complex structural formation while maintaining manufacturing simplicity.
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 method produces a rigid, self-supporting, fluid-impermeable composite pipe that maintains structural integrity and can be shaped like metal pipes, ensuring interchangeability with metal pipes while preventing porosity during bending.
Implementation Method 1
heating the product of steps (b) to (e) on the mandrel to a first temperature at which the thermoplastic materials of the one or more tapes and the tows melt and the heat-shrinkable layer shrinks radially inwards to consolidate the melted thermoplastic material
Implementation Method 2
heating the product of steps (b) to (e) on the mandrel to a first temperature at which the thermoplastic materials of the one or more tapes and the tows melt
Data Source
Figure 1~6
AI summary
A method of manufacturing a fluid impermeable rigid composite pipe (10) or hollow tube comprising the steps of :- a. providing a supporting mandrel (15) that is shaped to define a bore of the pipe (10); b. laying onto the outer circumferential surface of the mandrel (10) one or more first tapes (11) made of a thermoplastic material thereby to create a first region (11) that is predominantly thermoplastic material adjacent the bore of the pipe (10); c. providing a plurality of tows (14 ) that comprise co-mingled reinforcing fibres and thermoplastic filaments; d. weaving a plurality of the tows (14) to form one or more circular braids (13) and laying down the one or more of the circular braids (13) on to the first layer (11): to form a second region (12); e. applying to the outer surface of the second region (12) a heat-shrinkable layer (13); f. heating the product of steps (b) to (e) on the mandrel (15) to a first temperature at which the thermoplastic materials of the one or more tapes 11 and the tows 14 melt and the heat-shrinkable layer 13 shrinks radially inwards to consolidate the melted thermoplastic material to form a thermoplastic matrix in which the reinforcing fibres are embedded and a fluid impermeable thermoplastic rich region (11) is formed at the bore of the pipe (10); and, g. allowing the pipe (10) to cool to form a self supporting pipe(10)..