Folded Honeycomb Core Composite Manufacturing Method
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Solution Overview
Problem
Small-celled honeycomb cores used in aircraft construction lack drainage ability, leading to structural strength impairment and safety risks due to condensation, and their weight and anisotropic properties limit their suitability for modern large passenger aircraft fuselage sections, while folded honeycomb cores with drainage channels are difficult to wind and cover due to non-continuous surfaces.
Innovation Solution
A method involving arranging prepreg material on a tool to form lower and upper cover layers, introducing core filler material into a folded honeycomb core with full-length channels, hardening the composite under pressure and/or temperature, and removing the filler material to create a smooth, continuously curved surface with improved load flow and drainage, allowing for the manufacture of complete fuselage sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If small-celled honeycomb cores are used to prevent denting of cover layers, then aerodynamic and optical properties are improved, but drainage ability is lost and weight increases
Solution Approach 1:
The core structure is segmented into folded honeycomb channels that provide drainage pathways, separating the functions of surface smoothness (covered by layers) and drainage (provided by channels)
Solution Approach 2:
A liquid-absorbing core filler material is introduced as an intermediary substance within the folded honeycomb channels to absorb condensation and facilitate drainage, resolving the contradiction between smooth surface and drainage capability
2Shape
If small-celled honeycomb cores are used to prevent denting of cover layers, then aerodynamic and optical properties are improved, but weight increases
Solution Approach 1:
The cell size parameter of the honeycomb structure is changed from small-celled to folded honeycomb with larger channels, reducing weight while maintaining surface smoothness through cover layers and providing drainage capability
3Reliability
If folded honeycomb cores with drainage channels are used to enable drainage, then drainage ability and load flow configuration are improved, but surface continuity is lost
Solution Approach 1:
The core structure is segmented into folded honeycomb channels for drainage, while cover layers are applied over these channels to provide a continuous smooth surface, separating the drainage function from the surface continuity function
Solution Approach 2:
Liquid-absorbing core filler material is introduced as an intermediary within the channels to enhance drainage while the cover layers maintain surface continuity, resolving the contradiction between drainage capability and surface smoothness
4Strength
If folded honeycomb cores are used to improve load flow configuration, then structural strength is improved, but manufacturing difficulty increases
Solution Approach 1:
The folded honeycomb core structure is prepared in advance with predetermined fold lines and channels, and liquid-absorbing core filler material is introduced before applying cover layers, simplifying the manufacturing process while maintaining structural strength
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 core composite with ideal aerodynamic, static, and optical properties, enabling the manufacture of complete fuselage sections with enhanced structural strength and reduced weight, addressing the limitations of conventional honeycomb cores.
Implementation Method 1
The channels ensure a rapid reliable discharge of water
Implementation Method 2
hardening the fibre-reinforced layer
Data Source
AI summary
The invention relates to a method for manufacturing flat, single or double curved core composites 1, 23 with at least one folded honeycomb core 4, 19. Prior to applying the initially not yet hardened cover layers 2, 3, 13, 22 a curable and later removable core filler material 15, 16 is introduced into full-length drainage-enabling channels 5, 6 of the folded honeycomb core 4, 19 in order to prevent telegraphing of the cover layers 2, 3, 13, 22 into the channels 5, 6 of the folded honeycomb core when arranging and/or hardening the cover layers 2, 3, 13, 22 and to produce edge-free and polygon-free surfaces of the core composite 1, 23. The core composites 1, 23 made according to the method have optimum structural mechanical properties, an ideal surface quality from the aerodynamic and aesthetic point of view, whereby a direct reprocessing of the core composites 1, 23 is possible without the need for further time and cost-intensive as well as in some circumstances weight-increasing finishing steps. With the method it is possible to manufacture in particular one-piece fuselage sections with wound core composites 1, 23 with a folded honeycomb 4, 19 as well as shell segments with laid cover layers 2, 3, 13, 22 for longitudinally divided (segmented) fuselage sections for large aircraft.