Aircraft Acoustic Panel With Nested Honeycomb Elements
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Solution Overview
Problem
Conventional acoustic attenuation panels for aircraft engine nacelles face challenges in adapting to varying noise frequencies without increasing weight and size, particularly when dealing with lower frequency noise from fans of larger diameter and reduced rotation speed.
Innovation Solution
The acoustic panel incorporates transverse recesses with elongated acoustic elements of different shapes and materials, which are fixed within the panel to enhance sound absorption across a broader frequency range without significantly increasing bulk or weight, utilizing a combination of sound-absorbing materials and structures like honeycomb or foam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the thickness of the cellular structure is increased to absorb lower frequency noise, then the sound absorption capability is improved, but the weight and size of the panel increase
Solution Approach 1:
The patent embeds acoustic elements within the cellular structure of the panel. These elements are nested inside the existing honeycomb cells, allowing the panel to absorb lower frequency noise without increasing the overall panel thickness. The acoustic elements are positioned within the cellular structure's internal volume, effectively utilizing the existing space to enhance sound absorption capabilities across a broader frequency range while maintaining the original panel dimensions and weight.
2Adaptability or versatility
If the thickness of the cellular structure is increased to absorb lower frequency noise, then the sound absorption capability is improved, but the surface area and drag increase
Solution Approach 1:
The acoustic elements are nested within the existing cellular structure, allowing the panel to maintain its original external dimensions and surface area while enhancing sound absorption. This nesting approach enables the panel to absorb lower frequency noise without increasing the overall panel size or drag characteristics.
3Adaptability or versatility
If acoustic elements are added to the panel to broaden frequency absorption, then the sound absorption capability is improved, but the complexity of the panel structure increases
Solution Approach 1:
The patent combines the acoustic elements with the existing cellular structure by embedding them within the honeycomb cells. This merging approach integrates the noise absorption function into the structural framework of the panel, allowing the same structural elements to serve dual purposes: maintaining panel integrity and absorbing sound across a broad frequency range. The acoustic elements are positioned to work synergistically with the cellular structure rather than adding separate, complex systems.
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 design effectively absorbs a wider range of noise frequencies with minimal weight and size increase, improving noise attenuation while maintaining structural integrity and aerodynamic efficiency.
Implementation Method 1
a plate (2) made of a sound-absorbing material (3)
Implementation Method 2
acoustic elements (8) which are elongated to extend down in to the recesses (7)
Data Source
AI summary
An acoustic panel (1) includes a plate (2) made of an acoustic absorbing material (3), as well as a resistive skin (4) and a backing skin (6) arranged respectively on both sides of the plate (2), the acoustic panel (1) including acoustic elements (8) able to carry out an acoustic absorption, each of them being arranged in a housing (7) provided in the plate (2) with an opening (9) in front of the resistive skin (4). The combination of the plate (2) and the acoustic elements (8) allows to combine the sound attenuation properties of these two types of elements and to increase the frequency range of sounds that can be attenuated by the acoustic panel (1), without increasing the dimension.