Acoustic Panel Edge Jointing with Unobstructed Cell Openings
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Solution Overview
Problem
Existing methods for joining acoustic panels in aircraft nacelles block sound wave openings, reducing the effective acoustic area and sound attenuation capability, as foaming adhesives and mechanical joints obstruct cell openings and prevent sound wave penetration.
Innovation Solution
A joining system using thin, imperforate edge strips and blind fasteners to connect acoustic panels, ensuring that cell openings remain unobstructed, with the strips covering cell wall openings and the fasteners securing the panels without blocking sound wave pathways.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If foaming adhesive is used to join acoustic panel edges, then the panels are connected together, but the adhesive blocks cell openings and reduces sound attenuation capability
Solution Approach 1:
The joining function is extracted from the adhesive material itself and transferred to a separate mechanical fastening system (blind fasteners). This allows the adhesive to be replaced by a method that does not block cell openings, thereby preserving sound attenuation capability while maintaining joint strength.
Solution Approach 2:
Blind fasteners are introduced as an intermediary joining mechanism that connects panels through the outer skin without interfering with the inner skin or cell openings. This mediator enables structural connection while leaving the acoustic pathway unobstructed.
2Strength
If mechanical joints with inner plates are used to connect acoustic panels, then the panels are securely joined, but the inner plate blocks openings in the inner skin and prevents sound wave entry
Solution Approach 1:
The inner plate component that blocks sound pathways is completely removed from the design. The joining function is extracted and relocated to blind fasteners that attach only to the outer skin, eliminating the conflict between structural connection and acoustic performance.
Solution Approach 2:
The joining mechanism is moved from the inner dimension (inner skin level) to the outer dimension (outer skin level). Blind fasteners engage with the outer skin structure, placing the joining action in a different spatial dimension that does not interfere with sound wave propagation through the inner skin openings.
3Stability of the object's composition
If conventional joining methods are used, then panels are connected along longitudinal seams, but openings and cells proximate to the joint are blocked
Solution Approach 1:
The joining system is designed with local differentiation: blind fasteners are positioned specifically at the outer skin level away from cell openings, while cell openings in the inner skin remain locally unobstructed. This localized arrangement maintains connection stability where needed while preserving acoustic area where required.
Data Source
AI summary
The invention includes a joint assembly for connecting first and second longitudinal edges of portions of an acoustic barrel or panel having an open cell core, a perforated inner skin, and an outer skin. The joint assembly includes at least one strip covering a plurality of openings in walls of cells along the first and second longitudinal edges. The strip is separate from the inner and outer skins. A plate includes a first portion connected to the outer skin proximate to the first longitudinal edge, and a second portion connected to the outer skin proximate to the second longitudinal edge.