Composite Blade Anchoring Assembly Without Drilling Damage
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Solution Overview
Problem
Existing methods for assembling metal foils with composite material blades face issues such as detachment due to stress and aerodynamic mismatch, requiring additional operations like drilling, which can damage the blade and complicate assembly with complex shapes.
Innovation Solution
A mechanical anchoring element is inserted into the composite material part during the weaving process, creating a debonding zone for enhanced bonding without drilling, allowing adaptation to shear stress levels and ensuring a strong, aerodynamic fit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a bead of glue is used to bond the metal foil to the composite blade, then the assembly process is simple, but the bonding strength is insufficient under deformation and centrifugal force
Solution Approach 1:
The bonding system is segmented into multiple components: the original glue bead bonding and the additional mechanical anchoring element inserted into the composite material. This segmentation allows each component to contribute differently to the overall bonding - the glue provides initial adhesion while the mechanical anchoring element provides structural reinforcement against deformation and centrifugal forces.
Solution Approach 2:
The solution employs a composite bonding approach combining chemical bonding (glue bead) and mechanical bonding (anchoring element). The mechanical anchoring element itself is a composite structure consisting of a core and external elements, creating a multi-level composite system that leverages the advantages of both bonding mechanisms to achieve superior strength under various loading conditions.
2Strength
If drilling and machining operations are performed to insert mechanical anchoring elements, then the bonding strength is improved, but the composite material part is locally damaged
Solution Approach 1:
The mechanical anchoring element is inserted into the composite material part before the resin injection step, while the preform is still in its green state. This preliminary action allows the anchoring element to be positioned and secured without requiring drilling or machining operations that would damage the final composite structure. The element becomes integrated into the composite during the molding process itself.
Solution Approach 2:
The design anticipates potential damage from mechanical insertion by providing a pre-formed debonding zone within the fiber preform structure. This zone acts as a cushion or buffer that accommodates the mechanical anchoring element without compromising the integrity of the surrounding composite material, preventing stress concentration and potential failure points.
3Manufacturing precision
If the foil assembly means is designed to match complex blade shapes, then the aerodynamic fit is improved, but the assembly complexity increases
Solution Approach 1:
The mechanical anchoring element is designed with local quality variations - a core portion for insertion and external elements for bonding - allowing it to adapt to local geometric requirements of the blade surface. The element can be positioned and oriented to match specific local features of complex blade shapes without requiring the entire assembly means to be complex, achieving aerodynamic fit through localized adaptation.
Data Source
Figure 1~3
Figure 4~6
AI summary
The invention relates to an assembly of two parts (2, 4), one of the parts (4) being made of a composite material having a fibrous reinforcement obtained from a fibrous preform created by means of three-dimensional weaving and densified by a matrix. The assembly includes a mechanical anchoring element (12) that is secured to one of the parts and inserted inside the other part.