Aircraft Acoustic Panel Repair Using Vacuum-Formed Perforation Templates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing repair methods for acoustic panels in aircraft nacelles often diminish the acoustic properties due to misaligned perforations between replacement patches and existing top skins, leading to suboptimal noise attenuation.
Innovation Solution
A method involving the creation of a replacement patch with a core, ramp, and overlap portions, where a maskant is used to blast perforations, a fiberglass ply is used to match the perforation pattern, and the patch is aligned and bonded to the acoustic panel, ensuring accurate alignment and retention of acoustic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If existing repair techniques use overlapping patches without aligned perforations, then the repair process is simple and quick, but the acoustic properties are diminished in the overlap area
Solution Approach 1:
The method creates dimples in the fiberglass ply before bonding to anticipate and accommodate the perforations that will be drilled later. This preliminary action ensures that when perforations are made, they will be properly positioned to align with the existing panel perforations, thus preserving acoustic properties while maintaining a straightforward repair process
Solution Approach 2:
The fiberglass ply acts as an intermediary layer between the patch and the acoustic panel. By creating dimples in this intermediary layer that correspond to the perforation locations, the method ensures proper alignment and transmission of acoustic properties through the repair area without requiring complex alignment procedures
2Manufacturing precision
If perforations are drilled after bonding the patch, then alignment with existing perforations is difficult to achieve, but drilling before bonding risks damaging the bond
Solution Approach 1:
The method performs preliminary actions (creating dimples) in the fiberglass ply before bonding the patch, but delays the actual perforation drilling until after bonding. This sequence allows the patch to be securely attached first, then enables precise drilling of aligned perforations through both the patch and existing panel without compromising the bond
Solution Approach 2:
The method replaces complex mechanical alignment systems with a simpler dimple-based positioning system. The dimples created in the fiberglass ply serve as guides for perforation alignment, eliminating the need for complex jigs or alignment fixtures while ensuring precise perforation alignment with the existing panel
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 effectively repairs acoustic panels by maintaining the original perforation pattern, thereby preserving the acoustic properties and ensuring effective noise attenuation.
Implementation Method 1
The acoustic panel and the fiberglass ply may be placed in a bag, and a vacuum may be created within the bag. The dimples may be created using a pressure differential.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An acoustic panel (300) for an aircraft nacelle may comprise a perforated first skin, a second skin, and a core sandwiched between them. A damaged portion of the perforated first skin may be removed. A fiberglass ply (510) may be coupled to the acoustic panel. A pressure differential may cause the fiberglass ply to form dimples (515) within the perforations of the first skin. The fiberglass ply may be used as a template to drill holes in a replacement patch (400).