Non-metallic Sleeve Fastening for Composite Panels
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Solution Overview
Problem
Existing fastening systems for sandwich-structured composite panels to support structures are costly, prone to local buckling failures due to overtightening, require multiple installation phases, and create thermal bridges, limiting re-usability and increasing costs.
Innovation Solution
A fastening system using a non-metallic, galvanically isolating, and thermally insulating sleeve with a collar flange, which guides a short fastener through pre-manufactured holes in the panel, ensuring secure attachment without overtightening risks and eliminating the need for extensive screwing and flashing components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If long screws are used to fasten panels through the entire thickness, then secure attachment is achieved, but cost increases and risk of local buckling failures increases
Solution Approach 1:
The fastening system is divided into multiple components: a collar portion that remains in the panel and provides bearing surface, and a separate fastener that attaches to the support structure. This segmentation allows the fastening function to be achieved without a single long screw penetrating the entire panel thickness, thereby reducing the risk of local buckling failures while maintaining secure attachment.
Solution Approach 2:
The collar acts as an intermediary element between the panel and the support structure. It provides a bearing surface that distributes the fastening load over a larger area, preventing local buckling of the panel face skin while still achieving secure attachment to the support structure through the separate fastener.
2Reliability
If long screws are used to extend beyond panel thickness, then proper fastening is achieved, but cost increases
Solution Approach 1:
The fastening system segments the traditional single long screw into two separate components: a collar portion that is shorter and remains in the panel, and a fastener that attaches to the support structure. This segmentation allows using shorter, less expensive materials while achieving the same fastening function.
3Reliability
If traditional fastening with long screws is used, then attachment is achieved, but thermal bridges are created in building envelope
Solution Approach 1:
The collar serves as a thermal break intermediary between the metal panel and the support structure. By using a non-metallic collar material, the system achieves attachment functionality while preventing direct thermal conduction paths that would create thermal bridges in the building envelope.
4Reliability
If multiple flashings and connectors are used for installation, then proper coverage is achieved, but installation complexity increases
Solution Approach 1:
The collar integrates multiple functions into a single component: it provides a bearing surface for the fastener, acts as a thermal break, serves as a mounting surface for flashings and connectors, and prevents water infiltration. This merging of functions eliminates the need for separate flashings and connectors, reducing installation complexity.
5Reliability
If broad flashings are used to hide failures, then aesthetic coverage is achieved, but installation phases increase
Solution Approach 1:
The collar is installed beforehand into recesses in the panel during panel installation, providing a prepared mounting surface. This prior preparation eliminates the need for subsequent installation phases to add separate flashings for both aesthetic coverage and functional purposes, reducing overall installation time and phases.
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 easy, fast, and cost-effective installation with reduced risk of panel damage, eliminates thermal bridges, and enhances re-usability by using shorter screws and minimizing screw holes, while preventing galvanic contact and reducing waste.
Implementation Method 1
The sleeve is made of non-metallic, galvanically isolating and thermally insulating material
Implementation Method 2
The sleeve is made of non-metallic, galvanically isolating and thermally insulating material
Data Source
Figure 1
Figure 2a~2b
Figure 3~4
AI summary
A fastening system for fastening sandwich-structured composite panels (1) to a support structure (2) comprises a sandwich-structured composite panel (1) and a fastener (6) for fastening the sandwich-structured composite panel (1) to the support structure (2). The fastening system comprises an installation hole (7) formed through the first face skin (3) and the core (5), and an elongated sleeve (8) insertable into the installation hole (7). The sleeve (8) is made of non-metallic, galvanically isolating and thermally insulating material. The sleeve (8) comprises a tubular portion (9) a hollow interior (12) defined by a side wall (13) of the tubular portion (9), a bottom wall (14) at a second end (11) and a collar flange (15) encircling an open mouth (16) at the first end (10).. The sleeve (8) has a length (L1, L2) extending in the installation hole (7) from the first face skin (3) towards the second face skin (4). The sleeve (8) forms an installation guide for the fastener (6) which is insertable into the interior (12) and fastenable through the bottom wall (14). When the sleeve (8) is in the installation hole (7), the collar flange (15) abuts against an outer surface (18) of the first face skin (3) and the fastener (6) fastened to the support structure (2) pressing the second face skin (4) against the support structure (2).