Composite Fastener Assembly for Single-Sided Part Attachment
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Solution Overview
Problem
Existing fastener systems for securing parts to composite structures, such as aircraft fuselages, require drilling numerous holes and access to both sides, which is labor-intensive, costly, and time-consuming, especially in complex geometries like aircraft skins.
Innovation Solution
A fastener system that secures parts to composite structures without drilling holes, using a receptacle embedded within the structure, a torque nail that expands the receptacle, and a collar plate to distribute forces, allowing for single-sided access and assembly, with components like a retainer and structural connector pre-assembled to simplify installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional bolts and nuts are used to secure parts to composite structures, then reliable mechanical connection is achieved, but installation becomes labor-intensive and requires access to both sides of the structure
Solution Approach 1:
The fastening system is divided into separate components: a receptacle embedded in the composite structure, a torque nail inserted from one side, and a collar plate applied to the opposite side. This segmentation allows the connection to be formed without accessing both sides simultaneously, as the collar plate can be applied after the torque nail is inserted and the receptacle is embedded.
Solution Approach 2:
The receptacle is pre-embedded into the composite structure before the torque nail is inserted. This preliminary action prepares the connection point in advance, allowing the torque nail to be inserted from one side and the collar plate to be applied from the other side without requiring simultaneous access to both sides during the fastening operation.
2Reliability
If holes are drilled through the composite structure for fastener installation, then secure mechanical connection is achieved, but the process becomes costly and time-consuming
Solution Approach 1:
The system separates the hole-drilling function from the fastening function. The receptacle is embedded in a pre-drilled hole, while the torque nail and collar plate form the actual mechanical connection. This allows the hole to be drilled once and reused for multiple fasteners, and enables the collar plate to be applied without drilling additional holes through the composite structure.
Solution Approach 2:
The receptacle is pre-embedded into the composite structure with the hole already prepared. This preliminary embedding action eliminates the need to drill holes during the fastening operation itself, allowing multiple fasteners to be installed in the same location without repeated drilling, thereby increasing installation productivity.
3Strength
If multiple fasteners are installed to secure structural components, then structural integrity is maintained, but the complexity and cost of installation increases significantly
Solution Approach 1:
The torque nail and collar plate are designed to work together as an integrated fastening system. The torque nail inserts into the receptacle and the collar plate applies force to the opposite side, combining these elements to create a single fastening operation that maintains structural integrity without requiring multiple separate fasteners or complex installation procedures.
Solution Approach 2:
The receptacle design allows it to serve multiple functions: providing a receiving cavity for the torque nail, distributing the load from the collar plate, and anchoring the fastening system within the composite structure. This multi-functionality reduces the need for additional specialized components, simplifying the overall fastening system while maintaining structural integrity.
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 solution reduces installation complexity and cost by eliminating the need for multiple access points and drilling, enabling faster and more efficient attachment of parts to composite structures while maintaining structural integrity.
Implementation Method 1
the torque nail is sized and shaped with respect to the receptacle such that it expands a receiving portion of the receptacle when pressed into the receiving portion
Implementation Method 2
the collar plate is configured to be embedded within the composite structure and to distribute forces from the torque nail being pressed into the receiving portion of the receptacle
Data Source
AI summary
Fastener systems may be used to couple a part to a composite structure such that at least a portion of the fastener system is embedded within the composite structure, and such that the fastener system may be installed via access to just one side of the composite structure. Examples of fastener systems include a receptacle that is inserted through at least one layer of the composite structure and a torque nail that is inserted into the receptacle, thereby expanding the receptacle into a collar plate, which is configured to distribute the forces from insertion of the torque nail. The collar plate is enclosed between respective laminates of the composite structure, such that the fastener system is configured to couple the part to the composite structure, either directly or via a structural connector, without the use of conventional drilling and bolting.