Wide Flange Nut Insert for Aircraft Wall Panels Without Decoring
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Solution Overview
Problem
Existing methods for attaching inserts to cored sandwich or composite panels in aircraft require large bonding cavities, leading to increased manufacturing time, adhesive usage, and potential cold bridges, while also compromising load distribution and cleanliness.
Innovation Solution
The wide flange insert configuration eliminates the need for decoring the panel by using a metallic or non-metallic bobbin with a flange that rests on the panel surface, allowing for secure attachment without wide cavities, utilizing a cap screw tool for bonding and featuring a sacrificial cover and threaded pin for secure positioning during adhesive curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If large bonding cavities are created in the panel core using hand tools, then the load carrying capacity is improved, but the manufacturing time and complexity increase
Solution Approach 1:
The insert is divided into distinct functional segments: a narrow bonded shaft for adhesive attachment, a threaded section for fastener engagement, and a wide flange for load distribution. This segmentation allows each portion to be optimized independently - the narrow shaft minimizes bonding cavity requirements while the wide flange provides sufficient load distribution area, eliminating the need for large overall cavities and reducing manufacturing time.
Solution Approach 2:
The load distribution function is moved from the bonding cavity dimension to the flange dimension. Instead of distributing loads through a large cylindrical cavity, the wide flange distributes loads across a broad surface area at the panel face, transitioning the load distribution mechanism to a different dimensional approach that requires minimal core removal.
2Strength
If large bonding cavities are created in the panel core, then the load distribution is improved, but the adhesive requirement and weight increase
Solution Approach 1:
The insert design concentrates adhesive application to the local region at the shaft-panel interface, where bonding is most critical. The narrow shaft requires minimal adhesive volume while the wide flange provides mechanical load distribution without adhesive. This local quality approach applies adhesive only where structurally necessary, reducing total adhesive consumption while maintaining load distribution through the flange's geometric design.
3Reliability
If wide cavities are created in the core for insert installation, then the insert attachment is secured, but potential cold bridges are created in chilled compartments
Solution Approach 1:
The adhesive plug that traditionally filled the bonding cavity is extracted or eliminated from the design. Instead of requiring a large adhesive-filled cavity to secure the insert, the narrow shaft provides sufficient bonding surface area, and the wide flange provides mechanical retention through bearing contact with the panel face. This extraction of the adhesive plug eliminates the cold bridge pathway that would otherwise conduct thermal energy through the chilled compartment wall.
4Ease of manufacture
If hand tools are used to create bonding cavities, then the insert can be installed, but the process cleanliness and precision are reduced
Solution Approach 1:
The installation process transitions from static hand tool operation to dynamic automated drilling and insertion. The narrow shaft design enables automated drilling tools to create precise bonding cavities with controlled dimensions, and automated insertion equipment can precisely position and press the insert into place. This dynamic automated process improves both precision and cleanliness compared to manual hand tool operations.
Data Source
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AI summary
An aircraft wall panel (26) has a hole (28) going from a first (29) to a second side (31) and comprises a wide flange insert (12) located in the hole (28) for providing an attachment point for attaching and anchoring a component to the panel (26). A space in the hole (28) around the wide flange insert (12) is filled with adhesive material (32). A tubular nut (20) is disposed within the insert (12) as a floating nut.