Compressible Fan Blade Root Spacer for Impact Energy Dissipation
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Solution Overview
Problem
Existing spacers in gas turbine engines lack improved impact robustness and are not easily manufacturable, particularly in designs that need to absorb energy from bird strikes effectively while minimizing damage to fan blades.
Innovation Solution
A spacer comprising a first layer of injection molded polyimide resin with a durometer value of 78-82 D scale and a second layer of compressible rubber-type material with a durometer value of 60-70 A scale, which can be over-molded or bonded using thermal compression or adhesives, is used between the blade root and hub to dissipate energy during impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid spacer is used to provide support to the blade, then structural support is improved, but impact energy absorption is worsened
Solution Approach 1:
The spacer combines a rigid polyimide resin layer (providing structural support with durometer 78-82 D) and a compliant rubber-type material layer (absorbing impact energy with durometer 60-70 A), creating a composite structure that simultaneously achieves both structural integrity and energy absorption capabilities
Solution Approach 2:
Different regions of the spacer have different material properties: the first layer contacts the blade root and provides rigid support, while the second layer contacts the hub and provides compliant energy absorption, allowing each region to perform its specific function optimally
2Reliability
If a multilayer structure with different materials is used to absorb impact energy, then impact robustness is improved, but manufacturing complexity is worsened
Solution Approach 1:
The spacer is divided into two distinct layers with different materials and properties, allowing each layer to be optimized for its specific function (rigid support vs. compliant energy absorption) while simplifying the manufacturing process through sequential molding or bonding operations
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-layer spacer effectively absorbs and dissipates impact energy, reducing the likelihood of damage to fan blades and engines by transferring energy away from the point of impact, thereby enhancing robustness and ease of manufacturing.
Implementation Method 1
a second layer of compressible rubber-type material with a durometer value of 60-70 on an A scale... which can be over-molded or bonded using thermal compression or adhesives, is used between the blade root and hub to dissipate energy during impacts
Implementation Method 2
The first layer can be bonded to the second layer using a thermal compression process
Data Source
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AI summary
A spacer for use in a hub and blade assembly of a gas turbine engine including a first layer of a first material forming the spacer body having an elongate shape. The first material has a first stiffness. A second layer of a second material is mechanically attached to the first layer. The second material has a second stiffness different from the first stiffness.