Embedded Composite Fastener Assembly for Single-Sided Attachment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fastener systems for securing parts to composite structures, such as aircraft fuselages, require drilling numerous holes and access from both sides, which is labor-intensive and costly, especially in complex geometries like aircraft fuselage barrels.
Innovation Solution
A fastener system comprising a receptacle embedded within the composite structure, a torque nail that expands the receptacle, and a collar plate to distribute forces, allowing secure attachment without drilling through the composite and with single-sided access, using a preassembled fastener assembly with a structural connector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional bolts and nuts are used to secure parts to composite structures, then reliable connection is achieved, but access to both sides of the composite structure is required and drilling numerous holes is needed
Solution Approach 1:
The fastener 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 torque nail to be inserted through the composite structure from one side only, while the collar plate provides the locking function from the other side, eliminating the need for bilateral access during installation.
Solution Approach 2:
The torque nail is inserted into and expands within the receptacle, with the collar plate then applied over the receptacle and torque nail assembly. The collar plate nests over the receptacle, and the torque nail nests within the receptacle, creating a nested configuration that allows secure attachment from one side while maintaining connection reliability.
2Productivity
If traditional fastening methods with multiple holes are used, then secure attachment is achieved, but labor intensity and installation time increase
Solution Approach 1:
The receptacle is pre-embedded in the composite structure during manufacturing, and the collar plate is prepared in advance. This preliminary preparation eliminates the need for drilling holes during installation and allows the torque nail to be simply inserted and expanded, dramatically reducing installation complexity and increasing productivity.
3Reliability
If the receptacle expands when the torque nail is inserted, then secure locking is achieved, but the receiving portion may expand beyond acceptable limits
Solution Approach 1:
The receptacle is designed with specific local properties: the receiving portion is configured to expand when the torque nail is inserted, while the collar plate is designed with a friction fit that provides controlled resistance. This local differentiation allows the receiving portion to expand sufficiently for locking while the collar plate's friction fit prevents excessive expansion, maintaining manufacturing precision.
Solution Approach 2:
The system utilizes controlled parameter changes: the torque nail expansion changes the volume and shape of the receiving portion, while the collar plate's friction fit parameter provides resistance to this expansion. The interaction between these parameter changes ensures reliable locking while controlling expansion within acceptable limits.
4Ease of operation
If a preassembled fastener assembly is used, then installation is simplified, but the receptacle may require compression and plastic deformation during assembly
Solution Approach 1:
The receptacle is pre-formed with yield regions that are designed to deform in a controlled manner during assembly. This preliminary design of the deformation characteristics allows the receptacle to be compressed and plastically deformed as needed during fastener assembly installation, simplifying the assembly process while managing the complexity of deformation through pre-planned structural features.
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
Enables efficient and cost-effective attachment of parts to composite structures by eliminating the need for multiple holes and two-sided access, reducing labor and material waste while maintaining structural integrity.
Implementation Method 1
the torque nail may be sized and shaped with respect to the receptacle such that it expands the receiving portion of the receptacle when pressed into the receiving portion
Implementation Method 2
the collar plate may be 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
Figure 1
Figure 2
Figure 3
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.