Aircraft Sound Absorption Element With Interconnected Honeycomb Cells

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Solution Overview

Problem

Existing sound absorption elements for aircraft components, such as engine nacelles, do not provide adequate noise dampening performance and are not manufactured in a simple or economical manner.

Innovation Solution

A sound absorption element comprising a sandwich structure with a permeable face-sheet, a reflective back-sheet, and a honeycomb layer with interconnected cells, where each group of cells is acoustically independent, enhancing noise dampening by allowing sound waves to resonate and cooperate within the cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional sound absorption elements are used in aircraft components, then manufacturing simplicity is maintained, but noise dampening performance is insufficient

Engineering Contradiction:
Improvenoise dampening performanceVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sound absorption element is divided into multiple cells (first cells and second cells) separated by partition walls, with each cell type having specific functions. This segmentation allows different regions to handle different aspects of sound absorption, improving overall performance while maintaining a systematic structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the element have different properties: first cells are configured for specific acoustic functions while second cells have different configurations. The partition walls and communication holes are strategically placed to create local variations in acoustic impedance, enhancing noise dampening at different frequencies and locations

Inventive Principle:
Principle #3Local quality

2Reliability

If complex sound absorption structures are implemented, then noise dampening performance improves, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveacoustic insulation performanceVSAvoidmanufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Multiple functional elements are combined into a single integrated structure: the partition walls serve both as cell separators and as mounting surfaces for communication holes; the face-sheet integrates perforations and raised portions; the back-sheet combines reflective surfaces with structural support. This merging reduces the number of separate components and assembly steps

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The partition walls serve multiple functions: they define cell boundaries, provide mounting surfaces for communication holes, and create the structural framework for the entire element. The face-sheet simultaneously provides structural integrity, acoustic entry points through perforations, and flow management through raised portions

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 proposed solution significantly improves noise dampening performance by allowing sound waves to resonate and cooperate within the cells, providing better acoustic insulation while being manufactured in a cost-effective and straightforward manner.

Implementation Method 1

allowing sound waves to resonate and cooperate within the cells

Methodology Applied
Scientific EffectSound wave resonance: Resonance

Implementation Method 2

sound absorption element comprising a sandwich structure with a permeable face-sheet, a reflective back-sheet, and a honeycomb layer with interconnected cells

Methodology Applied
Scientific EffectAcoustic absorption: Acoustic Absorption

Implementation Method 3

a reflective back-sheet

Methodology Applied
Scientific EffectSound wave reflection: Reflection

Data Source

PatentEP2788601B1Element for sound absorption mounted on aircraft components
Publication Date: 2019.03.13 LEONARDO SPA
  • EP2788601B1 patent drawingFigure 1
  • EP2788601B1 patent drawingFigure 2
  • EP2788601B1 patent drawingFigure 3

AI summary

Element (26) for sound absorption, in particular intended for being mounted on components of aircrafts, such as engine nacelles. The element comprises a face-sheet (28), which is, at least in a region thereof, acoustically permeable, a substantially sound-reflective back- sheet (30) and a honeycomb layer (32), "sandwiched" between the face-sheet (28) and the back-sheet (30) and defining a mesh structure which has a plurality of hollow cells (34, 34') laterally neighboring one another. Said cells (34, 34') are adapted to make the sound waves that enter through the face-sheet (28) and are reflected by said back-sheet (30) resonate inside their side walls. The element (26) has a passage (36) that connects together a group of said cells (34, 34'), thereby causing them to acoustically cooperate with one another.