Composite Fastener Assembly for Insulation Blankets
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Solution Overview
Problem
Existing fastener assemblies for affixing thermal insulation blankets to aircraft engine nacelles are heavy, complex, and have poor adhesive bonding due to metal materials, leading to high costs and reduced thermal protection.
Innovation Solution
A fastener assembly comprising a composite or plastic attachment member with a metal threaded component and a cap fastener made of composite or plastic with a metal threaded extension, featuring a radially enlarged cap member and a circular recess for enhanced thermal insulation, reducing weight and complexity while maintaining strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If all-metal fasteners are used, then strength is improved, but weight increases and adhesive bonding deteriorates
Solution Approach 1:
The fastener assembly uses composite materials: the cap member is made of metal (stainless steel or Inconel) while the insulating material is made of ceramic or refractory composite. This combination provides the strength needed for high-temperature environments while reducing overall weight compared to all-metal fasteners and improving adhesive bonding through the ceramic/refractory material interface.
2Strength
If all-metal fasteners are used, then strength is improved, but adhesive bonding deteriorates
Solution Approach 1:
The cap member is made of metal (stainless steel or Inconel) while the insulating material is made of ceramic or refractory composite. This combination provides the strength needed for high-temperature environments while reducing overall weight compared to all-metal fasteners and improving adhesive bonding through the ceramic/refractory material interface.
3Temperature
If multiple components are assembled, then thermal protection is improved, but device complexity increases
Solution Approach 1:
The patent integrates the cap member, insulating material, and sealing features into a single unified assembly. The cap member includes an integrated seal groove and the insulating material is positioned within the cap member itself, eliminating the need for separate insulating components and simplifying the overall assembly process while maintaining thermal protection.
4Strength
If all-metal fasteners are used, then strength is improved, but manufacturing cost increases
Solution Approach 1:
The cap member is made of metal (stainless steel or Inconel) while the insulating material is made of ceramic or refractory composite. This combination provides the strength needed for high-temperature environments while reducing overall weight compared to all-metal fasteners and improving adhesive bonding through the ceramic/refractory material interface.
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 solution provides a lightweight, cost-effective fastener assembly with improved thermal protection by minimizing heat transfer through the circular insulating cavity, addressing the drawbacks of all-metal fasteners.
Implementation Method 1
the cap member has an inboard piece and an outboard piece forming an internal chamber. The cap's inboard piece and outboard piece are typically made of metal and an insulation material is positioned within the cap's central chamber
Implementation Method 2
Adhesive bonded attachments are well known for connecting a component to a threaded stud or bolt so as to mount components to a substrate. The base is then pressed against the substrate surface so as to allow the bonding agent to cure.
Data Source
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AI summary
A fastener assembly for affixing insulation blankets to a substrate is provided. The fastener assembly includes an attachment member having a construction for affixing to a substrate as well as a first fastener member preferably in the form of a male threaded stud. The fastener assembly further includes a cap fastener. The cap fastener includes a cap member and a second fastener member preferably in the form of a female threaded extension for threadably affixing to the first fastener member. The cap member has an exterior side and an interior side. The cap member's exterior side preferably has a shape for rotation by a tool. Meanwhile, the cap member's interior side has a circular recess concentric with the cap fastener's female threaded extension. When assembled, the circular recess forms a circular insulating cavity between the cap member and an insulation blanket.