Panel-Insert Assembly for Sandwich Panels
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for connecting sandwich panels to airframes using mechanical fasteners with threaded inserts are hindered by long adhesive cure times, added weight, and limited pull strength, as well as the risk of gaps or unintentional pullout due to improper insert placement.
Innovation Solution
A panel-insert assembly where the insert is positioned below a skin layer with an elongated opening, allowing 360-degree contact and direct load transfer, and a method involving forming an opening in the skin layer, inserting the insert, and rotating it for alignment, facilitating a strong connection without adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If threaded inserts are potted into holes with adhesives, then the inserts are secured to the sandwich panel, but the adhesive requires long cure times, adds undesired weight, and offers limited pull strength protection
Solution Approach 1:
The patent removes the adhesive from the connection system entirely, extracting the problematic bonding agent that caused long cure times and weight addition. The insert is secured through mechanical means only - by being potted into a recess formed in the core material, eliminating the need for adhesive curing while maintaining structural integrity.
Solution Approach 2:
The patent replaces the chemical bonding system (adhesive) with a pure mechanical securing system. The insert is held in place through mechanical interference fit within the recess, using physical constraints rather than chemical adhesion, thereby eliminating cure time requirements and adhesive weight.
2Strength
If threaded inserts are potted with adhesives, then the inserts are secured to the sandwich panel, but undesired weight is added
Solution Approach 1:
The adhesive material is completely removed from the assembly, extracting the source of unwanted weight. The connection is achieved through the recess geometry and mechanical interference fit alone, eliminating the need for additional adhesive mass while maintaining adequate connection strength.
3Ease of manufacture
If threaded inserts are placed too high in the holes, then the inserts are easier to install, but gaps are formed reducing connection quality
Solution Approach 1:
The recess is pre-formed in the core material at the correct depth and position before insert installation. This preliminary preparation establishes the precise final position of the insert, eliminating the need for precise placement during installation while preventing gap formation. The recess acts as a pre-positioned receptacle that guides the insert to its correct location.
4Ease of manufacture
If threaded inserts are placed too low in the holes, then installation is easier, but unintentional pullout occurs during tightening
Solution Approach 1:
The recess depth is carefully predetermined during core fabrication to provide optimal insert positioning. This preliminary action ensures the insert bottom sits at the correct depth within the core, preventing both gap formation and unintentional pullout during fastener tightening, while still allowing easy insert installation.
Solution Approach 2:
The recess geometry parameters (depth, width, shape) are optimized to provide the correct mechanical interference fit. By adjusting these geometric parameters, the system achieves reliable insert retention without requiring precise manual placement, as the recess itself provides the positioning constraints.
Data Source
AI summary
A panel-insert assembly including a panel having a core and a skin layer positioned over the core, wherein the skin layer defines an opening therein, and an insert positioned below the skin layer, wherein the insert is aligned with the opening.