Composite Fan Blade TLP Bonding Metallic Root
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Solution Overview
Problem
Existing methods for attaching composite airfoils to metallic roots face challenges due to undesirable features in the root design, which can lead to inadequate bonding and potential separation under stress or impact.
Innovation Solution
The integration of a metallic co-molded detail within the composite body, coupled with transient liquid phase (TLP) bonding, where a metallic interlayer is used between the co-molded detail and the attachment feature, allowing for a strong and durable bond that withstands high temperatures and mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional attachment methods are used to bond composite airfoils to metallic roots, then manufacturing simplicity is maintained, but bonding strength and structural integrity deteriorate due to undesirable root features
Solution Approach 1:
A metallic interlayer is introduced between the composite airfoil and the metallic root to act as an intermediary bonding surface. This interlayer enables effective bonding despite incompatible surface features of the root, resolving the contradiction by providing a mediating interface that ensures strong attachment without requiring modification of the root's undesirable features.
Solution Approach 2:
The attachment structure utilizes a composite construction combining metallic interlayer with composite bonding materials. This composite approach allows the system to leverage the advantages of both metallic (strength, temperature resistance) and composite (lightweight, design flexibility) materials to achieve superior bonding strength while managing structural complexity.
2Reliability
If simple bonding structures are used, then manufacturing ease is maintained, but reliability deteriorates due to potential separation under stress or impact
Solution Approach 1:
The metallic interlayer serves as a reliable intermediary that prevents direct contact between the composite airfoil and the problematic root features, thereby eliminating separation risks under stress or impact. This intermediary layer adds manufacturing steps but ensures attachment reliability by decoupling the bonding interface from the root's undesirable characteristics.
Solution Approach 2:
The bonding process utilizes transient liquid phase bonding with controlled temperature parameters to achieve reliable attachment. By precisely controlling the bonding temperature and interlayer diffusion parameters, the process transforms the attachment reliability from dependent on simple structure to dependent on controlled parameters, ensuring consistent performance under stress.
3Strength
If conventional bonding is used, then manufacturing simplicity is maintained, but bond strength under thermal and mechanical stress deteriorates
Solution Approach 1:
The bonding process employs transient liquid phase bonding with specific temperature control to achieve strong bonds that withstand thermal and mechanical stress. By changing the bonding parameters (temperature, time, pressure) and using a metallic interlayer with appropriate material properties, the system achieves superior bond strength despite increased process complexity.
Solution Approach 2:
The bonding process utilizes phase transitions of the metallic interlayer during heating and cooling cycles. The interlayer transitions between solid and liquid phases during bonding, then solidifies to create a strong, stress-resistant joint. This phase transition mechanism enables bonds that can withstand thermal and mechanical stresses that would fail conventional bonding.
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 solution provides a robust and reliable attachment of composite airfoils to metallic roots, enhancing the structural integrity and longevity of fan blades by creating a strong, isothermally solidified bond that maintains strength even at elevated temperatures and under shear forces.
Implementation Method 1
the interlayer may diffuse into at least one of the co-molded detail or the attachment feature
Implementation Method 2
The attachment feature may be bonded to the co-molded detail via transient liquid phase (TLP) bonding
Implementation Method 3
A bonding region comprising the interlayer may be heated to a bonding temperature
Implementation Method 4
maintaining the bonding region at the bonding temperature until the interlayer has isothermally solidified
Data Source
AI summary
The present disclosure relates to a method of manufacturing composite airfoils bonded to a metallic root. A composite body may be formed with a metallic co-molded member. The co-molded member may be transient liquid phase (TLP) bonded to a metallic root. The metallic root may allow the composite body to be attached to a rotor. The airfoil may also have a metallic edge which is TLP bonded to the composite body via a co-molded edge.