Flexible Composite Pipe Structure for Deep-Sea Stress Cracking
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Solution Overview
Problem
Current non-metallic flexible pipes used in deep-sea pipelines and marine risers face issues with stress cracking, poor temperature resistance, and inability to withstand harsh ocean environments, compromising safety and performance.
Innovation Solution
A non-metallic flexible pipe design featuring an inner liner, pressure-bearing layer, isolation layer, tensile layer, functional layer, and protective layer with non-rigid bonding, utilizing thermoplastic polymers and fiber-reinforced resin-based composites, and incorporating sensors and heat transfer elements, to enhance corrosion resistance, temperature, and pressure resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid bonding is used to connect adjacent layers, then the pipe structure has high strength and stability, but the pipe becomes prone to stress cracking and has poor temperature resistance
Solution Approach 1:
The patent changes the bonding parameter from rigid to flexible, allowing the pipe structure to adapt to stress and temperature variations without cracking, while maintaining overall structural integrity through the flexible bond's ability to deform and recover
Solution Approach 2:
The patent uses composite materials consisting of multiple layers with different properties (inner liner, reinforcement layer, functional layer, protective layer) bonded together with flexible bonding agents, creating a composite structure that combines the advantages of each material while mitigating their individual weaknesses
2Reliability
If multiple layers are bonded together to form a composite structure, then corrosion resistance and gas permeability resistance are improved, but the pipe loses flexibility and temperature resistance
Solution Approach 1:
The patent changes the bonding parameter from rigid to flexible, allowing the multi-layer composite structure to maintain flexibility while preserving the corrosion resistance and gas permeability resistance benefits of the layered composite design
Solution Approach 2:
The flexible bonding agent acts as an intermediary between the different layers, allowing relative movement and deformation while maintaining the bonded connection, thus preserving both the protective functions of the composite structure and the overall flexibility
3Temperature
If thermoplastic polymer and fiber-reinforced resin-based composite are used, then temperature and pressure resistance are improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-impregnating the fiber reinforcement with resin before assembly, and using extrusion to pre-form the thermoplastic polymer layers, which simplifies the subsequent bonding and manufacturing processes while achieving the required temperature and pressure resistance
Data Source
AI summary
A nonmetallic flexible pipe and a manufacturing method thereof. The nonmetallic flexible pipe comprises, from the inside to the outside, an inner liner, a pressure bearing layer, an isolation layer, a tensile layer, a functional layer, and a protective layer, wherein two adjacent layers are non-rigidly bonded. The inner liner layer is made from a thermoplastic polymer. The pressure bearing layer is made from a fiber-reinforced resin-based composite material. The isolation layer is made from a thermoplastic polymer. The tensile layer is made from a resin-reinforced fiber material. At least one of an optical fiber, a cable, a tracing ribbon, a pipe for conveying a heat transfer medium, a pressure sensor, and a temperature sensor is provided in the functional layer. The protective layer is made from a thermoplastic polymer.