Multilayer Gas Pipe Structure With Glassy Composite Reinforcement
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Solution Overview
Problem
Existing composite pipes for offshore oil and gas extraction face challenges with mechanical strength and thermal resistance due to the matrix's glass transition temperature being lower than the operating temperature, leading to rubbery behavior and reduced fatigue resistance, while high processing temperatures complicate tooling and process control.
Innovation Solution
A multilayer structure comprising a semi-crystalline thermoplastic polymer liner with a melting point below 280°C and a composite reinforcement matrix with a glass transition temperature greater than the maximum operating temperature, ensuring high rigidity and adhesion without increasing extrusion temperatures, using polymers like polyamides and polyetheretherketones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the same polymer is used for both the liner and the composite matrix to ensure adhesion, then adhesion between layers is improved, but the matrix becomes rubbery at operating temperature due to low glass transition temperature, reducing mechanical strength
Solution Approach 1:
The patent changes the glass transition temperature parameter of the composite matrix polymer to be higher than the operating temperature, transforming the matrix from a rubbery state to a glassy state, thereby improving mechanical strength while maintaining adhesion through compatible polymer selection
Solution Approach 2:
The patent uses composite materials consisting of high-strength fibers (such as carbon fibers) embedded in a polymer matrix with elevated glass transition temperature, creating a reinforcement structure that maintains rigidity and strength at operating temperatures while the liner provides sealing and adhesion
2Reliability
If high processing temperatures are used to process the liner, then adhesion to composite is improved, but tooling and process control become more complex
Solution Approach 1:
The patent modifies the processing temperature parameter by selecting polymers with appropriate melting and processing characteristics, enabling liner extrusion and bonding at reduced temperatures that simplify tooling requirements and improve process control while achieving sufficient adhesion to the composite reinforcement
3Strength
If the matrix remains in a glassy state at operating temperature, then mechanical strength and rigidity are improved, but processing temperature requirements increase
Solution Approach 1:
The patent optimizes the glass transition temperature parameter of the matrix polymer to strike a balance: high enough to ensure the matrix remains glassy at operating temperature for adequate strength and rigidity, but not so high that processing becomes excessively difficult, achieving this through careful selection of polymer chemistry and composition
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 solution provides enhanced mechanical strength, flexibility, and fatigue resistance while maintaining adhesion and processing feasibility, addressing the limitations of previous composite pipes by ensuring the matrix remains in a glassy state and the liner is flexible and resistant to chemical aggression.
Implementation Method 1
said sealing layers consisting of a composition predominantly comprising at least one semi-crystalline thermoplastic polymer P1i
Implementation Method 2
said at least one composite reinforcing layer consisting of a fibrous material in the form of continuous fibers impregnated with a composition predominantly comprising at least one thermoplastic polymer P2j, in particular semi-crystalline, said thermoplastic polymer P2j having a Tg, as measured according to ISO 11357-3:2013, greater than the maximum temperature of use of said structure (Tu)
Implementation Method 3
said innermost composite reinforcing layer being welded to said outermost adjacent sealing layer
Data Source
AI summary
A multilayer structure for transporting or storing gas including, from the inside to the outside, at least one sealing layer and at least one composite reinforcing layer, the innermost composite reinforcing layer being welded to the outermost adjacent sealing layer, the sealing layers being a composition predominantly including at least one semi-crystalline thermoplastic polymer P1i (i=1 to n, n being the number of sealing layers), the Tm of which is less than 280° C., and at least one of said composite reinforcing layers being a fibrous material in the form of continuous fibers impregnated with a composition predominantly including at least one thermoplastic polymer P2j, (j=1 to m, m being the number of reinforcing layers), the thermoplastic polymer P2j having a Tg greater than the maximum temperature of use of the structure (Tu), with Tg≥Tu +20° C., Tu being greater than 50° C.