Composite Fuselage Consolidation Using Induction-Heated Thermoplastics
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Solution Overview
Problem
Existing methods for fabricating large aircraft fuselage structures using thermoset composite materials are time-consuming, costly, and require significant facility resources, with autoclaves being inefficient and expensive.
Innovation Solution
A method and system using thermoplastic materials and induction heating to consolidate overbraided thermoplastic members with a thermoplastic skin, eliminating the need for autoclaves by employing smart susceptors for precise heating and cooling, and incorporating pressurization tubes and cauls for structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermoset composite materials are used to fabricate fuselage barrel sections, then structural integrity is achieved, but fabrication time and cost increase significantly
Solution Approach 1:
The patent changes the material parameter from thermoset to thermoplastic composite materials, which fundamentally alters the processing parameters. Thermoplastics can be processed using consolidation techniques that are much faster than autoclave curing, reducing fabrication time while maintaining structural integrity through controlled thermal and mechanical consolidation.
Solution Approach 2:
The patent replaces the mechanical/thermal system of autoclave curing with an inductive heating system. The induction heating apparatus directly heats the thermoplastic composite layers, eliminating the need for lengthy autoclave cycles and significantly reducing fabrication time while achieving equivalent or superior structural integrity.
2Reliability
If autoclave curing is used for thermoset composite materials, then complete curing is achieved, but equipment complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the autoclave equipment from the process by using induction heating directly on the composite layers. This removes the complex high-pressure, high-temperature autoclave system while achieving complete curing through controlled inductive heating and consolidation, significantly reducing equipment complexity.
Solution Approach 2:
The patent introduces an induction heating apparatus as an intermediary between the power source and the composite material. This intermediary system provides precise, controlled heating that achieves complete curing without requiring the complex autoclave system, acting as a simpler alternative that maintains curing reliability.
3Strength
If traditional thermoset composite fabrication methods are used, then structural strength is achieved, but production rate decreases
Solution Approach 1:
The patent changes the material class from thermoset to thermoplastic, which fundamentally improves the production rate. Thermoplastics can be consolidated and cured much faster using inductive heating, increasing productivity while maintaining structural strength through controlled thermal processing and consolidation parameters.
Solution Approach 2:
The patent replaces the slow autoclave curing process with rapid inductive heating. This substitution dramatically reduces the time required to achieve structural strength, thereby increasing production rate and productivity while maintaining or improving structural integrity through direct thermal consolidation.
4Strength
If thermoset composite materials are used, then structural integrity is achieved, but facility resources and tooling requirements increase
Solution Approach 1:
The patent extracts and eliminates the need for extensive facility resources and specialized tooling by using thermoplastic materials that can be processed with simpler equipment. The induction heating system requires minimal facility infrastructure compared to autoclave systems, reducing facility resource requirements while maintaining structural integrity.
Solution Approach 2:
The patent employs disposable or reusable consolidation fixtures and simple tooling instead of expensive, complex autoclave equipment. This approach reduces the investment in facility resources and tooling while achieving equivalent structural integrity through controlled thermal consolidation and pressing techniques.
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 reduces fabrication time and cost, enabling rapid production of composite fuselage structures with improved efficiency and reduced equipment complexity, allowing for seamless integration with other fuselage components.
Implementation Method 1
heating, inductively, the consolidation setup to consolidate the plurality of overbraided thermoplastic members with the overbraided thermoplastic skin
Implementation Method 2
The plurality of mandrels comprises a first material that is configured to generate heat in response to a magnetic field
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
A method and apparatus for forming a composite structure. A stackup comprising a plurality of overbraided thermoplastic members and an overbraided thermoplastic skin is built. The stackup is placed between an inner tooling and an outer tooling. The inner tooling, the stackup, and the outer tooling are held in place together using a load constraint. The inner tooling, the stackup, the outer tooling, and the load constraint form a consolidation setup. The consolidation setup is heated to form the composite structure.