Spraying Device for Sandwich Plate Honeycomb Core Repair
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Solution Overview
Problem
Existing methods for repairing damaged sandwich plates in aircraft, particularly floor plates with honeycomb cores, face challenges such as air bubble formation, destruction of the core structure, and high costs due to the need for removal and replacement, which complicates the repair process and reduces the structural integrity of the affected area.
Innovation Solution
A method involving the introduction of penetrating holes into the surface layer above damaged cells, injection of a stabilizing material into the cells, and subsequent filling with a filler material to restore the surface finish and mechanical stability without removing the sandwich plate, using a spraying device that can dispense either one-component or two-component curable resin systems to ensure even wetting and stabilization of the core structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If honeycomb cores are filled with curable synthetic resin material through drilled holes, then the core structure strength is improved, but air bubbles form and preferentially move into the region below the upper surface layer where maximum stabilisation is required
Solution Approach 1:
The patent uses a spraying device that delivers stabilizing material in a fluid state through pressurized spray nozzles, allowing the material to flow into the honeycomb cells and displace air bubbles effectively. The fluid delivery system enables complete cell infiltration without trapping air, solving the air bubble problem while maintaining strength improvement.
Solution Approach 2:
The patent changes the physical state and delivery parameters of the stabilizing material by using a sprayable fluid formulation instead of traditional viscous resin. This parameter change allows the material to be delivered under pressure through fine nozzles, ensuring complete wetting of cell walls and expulsion of air bubbles, thereby achieving both strength improvement and bubble-free infiltration.
2Strength
If a rotating hook is used to destroy the core structure and create a large cavity, then vertical stabilisation is improved, but destruction of the honeycomb-shaped core structure takes place over a large volume
Solution Approach 1:
The patent extracts only the essential function of creating stabilisation volume by using sprayed material that expands and fills the existing honeycomb cells, rather than mechanically destroying large volumes of core structure. This selective approach achieves vertical stabilisation while preserving the intact honeycomb architecture and minimizing material loss.
Solution Approach 2:
The sprayed stabilizing material acts as an intermediary that fills the spaces within the intact honeycomb structure, providing vertical stabilisation without requiring mechanical destruction. This mediator material penetrates and bonds with the existing core structure, achieving stabilisation while preserving the original honeycomb geometry.
3Manufacturing precision
If the floor plate is removed for repair, then even wetting of cell walls with stabilising plastic material is achieved, but the repair process becomes more complex and time-consuming
Solution Approach 1:
The patent employs a pressurized spray delivery system that projects the stabilizing material through nozzles directly into the honeycomb cells from the accessible surface. This pneumatic delivery method achieves complete and even wetting of cell walls while the plate remains installed, eliminating the need for removal and simplifying the repair process.
Solution Approach 2:
The patent changes the delivery dimension by spraying material vertically downward into the cells from the upper surface, rather than requiring access from multiple directions or plate removal. This dimensional approach to material delivery achieves uniform wetting while maintaining the plate in its installed position, reducing repair complexity.
4Ease of operation
If multiple drilled holes are introduced into the surface layer, then access to damaged cells is improved, but the number of holes increases the complexity of the repair process
Solution Approach 1:
The patent segments the delivery function by using multiple spray nozzles that can be positioned at different angles and locations on the surface. This segmentation allows material to be delivered through multiple pathways simultaneously, ensuring complete cell access and wetting while avoiding the need for large, visible drilled holes that would compromise surface 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 method allows for a rapid, cost-effective, and visually undetectable repair of damaged sandwich plates by ensuring full surface area wetting of the honeycomb cells, reducing curing time, and restoring the original surface finish while maintaining structural integrity, even if the original geometry of the cells cannot be fully restored.
Implementation Method 1
a stabilising material based on one component can be evenly sprayed, through a spraying tube and a nozzle fitted downstream of the tube, directly in the region of the honeycomb-shaped cells that are to be stabilised
Implementation Method 2
Injection of a stabilising material into the at least one cell
Data Source
AI summary
A method for the repair of a sandwich plate having a core structure, a top surface layer and a bottom surface layer and a plurality of honeycomb-shaped cells includes providing at least one penetrating drill hole in at least one of the top surface layer and the bottom surface layer above one of the plurality of honeycomb-shaped cells in a damaged region of the sandwich plate, injecting a stabilising material into the honeycomb-shaped cell, and filling the damaged region with a filler material.