Adhesive-Reinforced Aluminum Hollow Fan Blade Bonding
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Solution Overview
Problem
Adhesive bonds in fan blades, particularly in geared turbofan engines, face challenges due to varying stress concentrations and moisture ingress, leading to reduced bond strength and durability, which can result in cracks and safety risks.
Innovation Solution
A dual adhesive system is implemented, where a polyurethane elastomer-based first adhesive bond is reinforced by a polyepoxide-based second adhesive layer with an erosion-resistant coating, applied to protect the bond from atmospheric moisture and enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If elastomer-based adhesives are used to bond the blade cover to the blade body, then flexibility and impact resistance are improved, but bond strength at elevated temperatures and environmental durability deteriorate
Solution Approach 1:
The patent applies a composite adhesive system consisting of an elastomer-based adhesive layer (for flexibility and impact resistance) combined with an epoxy-based adhesive layer (for high-temperature strength and environmental durability). This composite approach allows both adhesive types to work together, achieving properties that neither adhesive could provide alone in a single-layer configuration.
2Reliability
If epoxy-based adhesives are used to bond the blade cover to the blade body, then bond strength at elevated temperatures and environmental durability are improved, but flexibility and impact resistance deteriorate
Solution Approach 1:
The patent applies a composite adhesive system consisting of an elastomer-based adhesive layer (for flexibility and impact resistance) combined with an epoxy-based adhesive layer (for high-temperature strength and environmental durability). This composite approach allows both adhesive types to work together, achieving properties that neither adhesive could provide alone in a single-layer configuration.
3Reliability
If seals are added around the joint between the blade body and blade cover to protect from moisture ingress, then adhesive bond stability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent introduces a moisture-curing sealant as an intermediary material applied at the interface between the blade body and blade cover. This sealant acts as a barrier against moisture ingress while being integrated into the existing bonding process, avoiding the need for separate seal installation steps and reducing overall manufacturing complexity.
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 dual adhesive system significantly increases bond strength, impact resistance, and long-term durability while reducing moisture permeation, thereby ensuring the fan blades' stability and safety over extended periods.
Implementation Method 1
Elastomer-based adhesives provide excellent flexibility and impact resistance when used to bond the aluminum cover to the aluminum blade body
Implementation Method 2
The second adhesive layer is in a protective relationship with portions of the first adhesive bond that are exposed to the atmosphere
Implementation Method 3
Epoxy-based adhesives display enhanced bond performance at elevated temperatures and superior environmental durability
Data Source
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AI summary
Disclosed herein is a blade (200) for an engine comprising a blade cover (204) and a blade body (202). A first adhesive bond (206) is disposed between the blade cover (204) and the blade body (202). A second adhesive layer (208) is disposed on a surface of the blade cover (204) and a periphery of the blade body (202) that surrounds the blade cover (204). The second adhesive layer (208) is in a protective relationship with portions of the first adhesive bond (206) that are exposed to the atmosphere in the absence of the second adhesive layer (208).