Aircraft Repair Patch Joining Using Cold Spray Deposition
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Solution Overview
Problem
Existing aircraft structure repair methods, particularly for components like nacelle inlets, wings, and tails, are time-consuming and visually conspicuous due to the use of fasteners, and prone to corrosion, especially in thin structures, increasing maintenance costs and reducing operational reliability.
Innovation Solution
A method using cold spray powder deposition to join a repair patch with the aircraft structure, eliminating the need for fasteners by forming a groove along the edge and filling it with cold-sprayed powder, ensuring structural integrity and aerodynamic continuity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fastening techniques are used to join repair patch to aircraft structure, then structural integrity is restored, but repair time and complexity increase significantly
Solution Approach 1:
The patent replaces the mechanical fastening system (screws, bolts, rivets) with a cold spray deposition system that uses kinetic energy of sprayed particles to bond the repair patch directly to the substrate. This substitution eliminates the time-consuming steps of drilling, countersinking, and fastener installation while achieving comparable structural integrity through material deposition and bonding.
Solution Approach 2:
The patent extracts and removes the damaged portion of the aircraft structure to create a clean cut-out, eliminating the need for extensive fastening operations. By taking out the damaged area and filling it with deposited material, the repair process avoids the complexity of multiple fasteners and associated preparation steps.
2Shape
If multiple fasteners are installed for flush repair, then aerodynamic constraints are fulfilled, but repair visibility and complexity increase
Solution Approach 1:
The cold spray deposition system replaces the complex multi-fastener mechanical system with a continuous material deposition process. This eliminates the need for multiple discrete fasteners and their associated installation complexity, while the deposited material can be shaped to maintain aerodynamic profiles.
Solution Approach 2:
The patent merges the repair patch material with the surrounding substrate through cold spray deposition, creating a unified, continuous structure. This merging eliminates the discrete fastener elements and their visible traces, resulting in a seamless repair that maintains aerodynamic characteristics without the complexity of multiple connection points.
3Strength
If fastening joints are used for repair, then structural strength is restored, but corrosion risk increases at fastener locations
Solution Approach 1:
The patent replaces the fastening joint system with a cold spray deposition system that creates a continuous, seamless bond between the repair patch and substrate. This eliminates fastener holes and joints that would otherwise serve as corrosion initiation sites, particularly important in humid environments where sealant deterioration could occur.
Solution Approach 2:
The patent addresses the corrosion vulnerability of fastening systems by using cold spray deposition to create a corrosion-resistant repaired structure. The deposited material forms a continuous, sealed surface that prevents moisture ingress and eliminates the corrosion-prone fastener locations, effectively converting the vulnerability of mechanical joints into the advantage of a seamless, corrosion-resistant repair.
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
The method reduces repair time and costs, prevents corrosion, and maintains the aircraft's structural and aerodynamic integrity without visible fasteners, suitable for thin structures like engine air inlets.
Implementation Method 1
The aircraft structure and the repair patch are then joined to each other by using cold spray powder deposition technique, as powder material is cold sprayed into the groove
Data Source
Figure 1a~1c
Figure 1d~1f
Figure 1g~2b
AI summary
Disclosed is a method for repairing a damaged aircraft structure 10, 10'. The method comprises forming a cut-out C in the aircraft structure by removing a portion thereof which includes a damage, and closing the cut-out C with a repair patch 20, whereby a groove G, G' is formed along an edge 20e of the repair patch running along an edge 10e of the aircraft structure at the cut-out. The aircraft structure 10, 10' and the repair patch 20, 20' are joined to each other by cold spraying powder material 40 into the groove G, G'. Further disclosed is a repaired aircraft structure 100 comprising a repair patch 20, 20', an aircraft structure 10, 10' enclosing the repair patch 20, 20', and cold spray deposited powder material 40 joining the aircraft structure 10, 10' and the repair patch 20, 20'.