Airfoil Cover Panel Fastening for Lightweight Structural Strength
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Solution Overview
Problem
The challenge in manufacturing airfoils, such as fan blades, is to achieve strong bonding and structural strength while minimizing weight, which is compromised by the need for thick interfacial ribs to cover large surface areas.
Innovation Solution
The airfoil design incorporates a metal body with holes and a cover panel secured by push fasteners with flexible barbs that engage the holes, along with an adhesive layer, to provide securement and structural integrity without adding excessive weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is used to bond airfoil pieces together, then structural strength is achieved, but large surface area is required which necessitates thick interfacial ribs that add weight
Solution Approach 1:
The patent replaces the adhesive bonding system with a mechanical fastening system using push fasteners. These fasteners have barbs that engage with the airfoil pieces through friction and mechanical interlocking, eliminating the need for large adhesive surface areas and thick interfacial ribs, thereby reducing weight while maintaining bonding strength
Solution Approach 2:
The patent changes the bonding mechanism from chemical adhesion to mechanical fastening with friction-based retention. The push fasteners utilize friction between the barbed surface and the airfoil pieces to provide strong bonding without requiring large contact areas, thus avoiding the weight penalty of thick ribs
2Weight of moving object
If push fasteners with barbs are used to secure cover panel, then weight is reduced compared to adhesive bonding, but manufacturing precision is required for proper engagement
Solution Approach 1:
The patent divides the fastening function into multiple discrete push fasteners distributed across the airfoil structure. Each fastener operates independently with its own hole, allowing for localized precision requirements rather than requiring entire rib structures to be precisely aligned, thereby reducing overall manufacturing precision demands
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 design effectively secures the airfoil pieces while reducing weight and maintaining structural integrity, enhancing the aerodynamic profile and operational efficiency of gas turbine engines.
Implementation Method 1
Each of the push fasteners has flexible barbs that engage sides of the holes to resist retraction of the fasteners from the holes
Implementation Method 2
An adhesive layer between the cover panel and the metal body
Data Source
AI summary
An airfoil includes a metal body that has holes, a cover panel carried on the metal body, and push fasteners that extend through the cover panel and into the holes to lock the cover panel on the metal body. Each of the push fasteners includes flexible barbs that engage sides of the holes to resist retraction of the fasteners from the holes. The heads of the push fastener are embedded in recesses in the cover panel.