Oblique-Cavity Acoustic Panel Bonding for Crush-Resistant Draping
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Solution Overview
Problem
Conventional acoustic panels in aircraft propulsion units face issues with reduced compressive strength due to angled cavities, leading to potential crushing during manufacturing and increased manual labor costs, especially when using automated draping operations.
Innovation Solution
A manufacturing method that includes a second heating step to bond the intermediate structure to the first skin, using a polymerizable adhesive, which increases the compressive strength of the intermediate structure, allowing for automated draping and reducing manufacturing costs without increasing panel mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cavities are angled to reduce footprint and attenuate low frequencies, then acoustic performance is improved, but compressive strength of the intermediate structure deteriorates
Solution Approach 1:
The adhesive material is applied to the first skin before the intermediate structure is placed, and the assembly is heated to polymerize the adhesive in advance. This preliminary bonding action secures the intermediate structure to the first skin before the second skin is added, preventing crushing during subsequent handling and automated draping operations.
2Productivity
If automated draping operations are used to reduce manufacturing cost, then productivity is improved, but the intermediate structure is crushed due to insufficient compressive strength
Solution Approach 1:
The intermediate structure is bonded to the first skin before the automated draping of the second skin. This preliminary bonding provides the necessary structural support to withstand the mechanical pressure (up to 1.5 MPa in geometric singularities) applied during automated draping operations, enabling crush-free manufacturing with automated equipment.
3Strength
If manual draping is used to avoid crushing the intermediate structure, then compressive strength is preserved, but manufacturing cost increases
Solution Approach 1:
By bonding the intermediate structure to the first skin before the second draping operation, the structure gains sufficient compressive strength to withstand automated draping. This eliminates the need for expensive manual draping operations while preserving the intermediate structure's integrity, thereby reducing manufacturing costs.
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 enhances the compressive strength of the intermediate structure from 0.2 MPa to 1.4 MPa, enabling automated draping operations and cost reduction while maintaining panel mass and density.
Implementation Method 1
a second step of heating the assembly formed by the first skin, the adhesive material and the intermediate structure, so as to polymerize the adhesive material
Data Source
AI summary
A method for manufacturing an acoustic panel including a first skin, a second skin and an intermediate structure enclosed between these skins and forming oblique cavities with respect to the latter. The method includes an intermediate polymerization step for fastening the intermediate structure to the first skin in order to increase the compressive strength thereof and in particular to support an automated operation of draping the second skin.