Composite Hinge Adhesive Bonding Structural Integrity
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Solution Overview
Problem
Existing hinges for composite materials are complex, expensive, and prone to structural weakening due to the difficulty in creating holes and adhesion issues with metal plates, limiting their use to angles less than 180° and requiring precise mechanical working, which increases costs and risks damage to the substrate.
Innovation Solution
A hinge and manufacturing process using a flexible substrate and dry carbon fiber layers incorporated in a cured and flexible resin, allowing easy adhesive fastening and integration in RTM processes, with a design that can absorb tolerances and reduce thickness for A-class components, and featuring a wear-resistant resin with specific mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If metal plates with holes are used for the hinge, then the hinge can be fastened to composite material parts, but the holes cause structural weakening of the composite material parts
Solution Approach 1:
The invention extracts the fastening function from mechanical holes and threaded members and replaces it with a continuous adhesive bond. The hinge plates are fastened directly to the composite material surfaces without penetrating holes, maintaining the integrity and structural strength of the composite parts while achieving secure attachment through surface adhesion.
Solution Approach 2:
The invention changes the fastening mechanism from mechanical (holes and threads) to chemical/adhesive (surface bonding). By altering the attachment method parameter, the hinge achieves secure fastening without compromising the structural strength of the composite material parts, as the adhesive bond distributes stress across the surface rather than concentrating it at hole locations.
2Ease of manufacture
If metal plates are used for the hinge, then the hinge can be fastened to composite material parts, but adhesion problems arise due to different physical and chemical features of the materials
Solution Approach 1:
The invention introduces an adhesive as an intermediary substance between the metal hinge plates and the composite material parts. This adhesive mediator bridges the physical and chemical differences between dissimilar materials, enabling reliable adhesion by chemically bonding to both surfaces and transferring loads effectively across the material interface.
Solution Approach 2:
The hinge construction employs a composite structure combining metal plates with adhesive bonding, creating a hybrid fastening system. This composite approach leverages the strengths of both metal (structural integrity) and adhesive (surface bonding capability), achieving reliable attachment between dissimilar materials through the synergistic combination of different material properties.
3Ease of operation
If grooves are made in the substrate to create a line of inflection, then the hinge can rotate, but the manufacture becomes complex and expensive requiring precise mechanical working
Solution Approach 1:
The invention segments the hinge into two separate components: a substrate and hinge plates, connected by adhesive bonds at specific locations. This segmentation eliminates the need for complex grooves and lines of inflection in the substrate, allowing each component to be manufactured independently using simpler processes, while the segmented adhesive bonding provides the necessary rotational capability.
Solution Approach 2:
The invention replaces the mechanical groove-based inflection system with an adhesive bonding system. Instead of using mechanical grooves cut into the substrate to create flexure, the hinge uses adhesive bonds that allow controlled rotation through their shear deformation, substituting a simpler chemical bonding process for complex mechanical working.
4Reliability
If grooves with V-shaped cross-section are used, then the substrate damage risk is reduced, but the hinge cannot rotate with angles greater than the summit angle of the groove
Solution Approach 1:
The invention creates a dynamic hinge system where the adhesive bonds can deform elastically during rotation, allowing the hinge to accommodate various rotation angles. The adhesive layer acts as a flexible element that can bend and shear, enabling rotation angles limited only by the adhesive's elastic range rather than by fixed geometric constraints like groove angles.
Solution Approach 2:
The invention uses thin adhesive films between the substrate and hinge plates to provide flexibility and enable rotation. These thin adhesive layers can bend and deform, allowing the hinge to rotate through angles greater than what would be possible with rigid groove structures, while maintaining substrate integrity through the flexible nature of the adhesive bond.
5Ease of operation
If the substrate is made thinner to accommodate grooves, then the hinge can rotate, but the substrate becomes more prone to breakings along the line of inflection
Solution Approach 1:
The invention provides beforehand cushioning by using the adhesive layer as a stress-distributing medium that prevents stress concentration at potential failure points. The adhesive bond spreads the rotational stresses uniformly across the substrate-hinge plate interface, preventing the formation of stress concentrations that would lead to breakings, thereby allowing rotation without compromising substrate strength.
Solution Approach 2:
The adhesive layer acts as a flexible film that accommodates rotation while distributing stresses uniformly. This thin flexible bonding layer allows the substrate to remain thin without compromising strength, as the adhesive compensates for the reduced substrate thickness by providing a compliant interface that prevents stress concentration and potential breakings during rotation.
6Reliability
If different resins are used for the layers and substrate, then the adhesion can be improved, but additional working is required to roughen the substrate
Solution Approach 1:
The invention uses the same resin type for both the substrate and the hinge plates, creating a homogeneous material system. This homogeneity eliminates adhesion problems between dissimilar materials and removes the need for additional surface preparation steps like roughening, as the identical resin chemistry ensures compatible bonding interfaces without requiring extra manufacturing complexity.
7Strength
If aramid and/or woven fibers are used for the substrate, then the hinge strength is improved, but the manufacture becomes more expensive and delicate
Solution Approach 1:
The invention changes the substrate material parameter from high-performance but complex aramid and woven fibers to a simpler unidirectional fiber reinforcement. This parameter change maintains sufficient hinge strength through optimized fiber orientation and adhesive bonding, while significantly reducing manufacturing complexity and cost by using more readily available and easier-to-process unidirectional fiber materials.
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 enables a simple, fast, and economic production of a hinge that can rotate beyond 180°, is aesthetically pleasing, and resistant to wear, while avoiding structural weakening and adhesion issues, making it suitable for various applications and reducing manufacturing costs.
Implementation Method 1
it can also be easily incorporated in these parts in RTM (Resin Transfer Molding), Light-RTM, VARTM (Vacuum Assisted Resin Transfer Molding) processes
Implementation Method 2
both the substrate and the layers are incorporated in a cured and flexible resin
Data Source
AI summary
A hinge is disclosed having at least two groups of layers of fibers arranged on and/or under two opposite edges, respectively, of at least one substrate of a material flexible and compatible for the adhesion with resins for composite materials, so that a central portion of the substrate is not covered by these layers, the substrate and the layers being incorporated in a cured and flexible resin. The present invention also relates to a process for manufacturing said hinge.