Honeycomb Acoustic Partition Structure for Broadband Sound Absorption

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Solution Overview

Problem

Existing sound absorption structures in aircraft propulsion systems face challenges such as increased mass, complex manufacturing processes, and difficulty in shaping due to numerous connections, and limited adjustable acoustic attenuation characteristics, particularly when aligning honeycomb structures for optimal performance.

Innovation Solution

A sound absorption structure with a partition system comprising a honeycomb structure interposed between acoustically resistive and reflective layers, featuring partition walls and conduits that split cells into two types of resonators, allowing independent adjustment of acoustic attenuation characteristics, and a hook-shaped tab for easy installation and alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple honeycomb structures are used to attenuate different frequency ranges, then the frequency range of sound attenuation is extended, but the mass of the structure increases and manufacturing complexity increases

Engineering Contradiction:
Improvefrequency range of sound attenuationVSAvoidmass of acoustic absorption structure
Core Design Contradiction:
Adaptability or versatilityVSWeight of stationary object

Solution Approach 1:

The patent divides a single honeycomb structure into multiple functional zones using partition walls. Each zone acts as an independent resonator tuned to different frequency ranges, achieving broadband attenuation without stacking multiple honeycomb structures. The partition walls create separate cavities within the same structural footprint, maintaining low mass while extending frequency coverage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent nests multiple resonator cavities within a single honeycomb structure by using internal partition walls. This creates a nested configuration where multiple functional chambers are contained within one external structure, achieving the effect of multiple structures while maintaining the mass and simplicity of a single unit.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Adaptability or versatility

If multiple honeycomb structures are connected with separation layers and tubes, then two types of resonators are formed, but the manufacturing process becomes more complex and alignment precision is increased

Engineering Contradiction:
Improveresonator typesVSAvoidmanufacturing process complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent segments the internal volume of each honeycomb cell using partition walls, creating distinct resonator chambers within a single continuous structure. This eliminates the need for separate honeycomb structures and their associated connection components, dramatically simplifying manufacturing while maintaining the ability to support multiple resonator types.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges multiple resonator functions into a single honeycomb structure by integrating partition walls that create different cavity configurations within the same structure. This combines what would traditionally require separate structures into one unified component, reducing assembly complexity and improving manufacturing ease.

Inventive Principle:
Principle #5Merging (Combining)

3Stability of the object's composition

If honeycomb structures are connected with links to separation layer, then structural integrity is maintained, but the structure becomes difficult to shape into curved profiles

Engineering Contradiction:
Improvestructural integrityVSAvoidcurved profile capability
Core Design Contradiction:
Stability of the object's compositionVSShape

Solution Approach 1:

The patent merges the partition walls directly with the honeycomb structure walls, creating a monolithic integrated structure. This eliminates separate connection components that would constrain shaping, allowing the entire structure including partitions to be formed as a single curved component, maintaining integrity while enabling complex geometries.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs thin partition walls that can be integrated into curved surfaces, allowing the structure to be formed into aerodynamic shapes. The partition walls are designed as thin elements that maintain structural integrity while conforming to curved profiles, enabling the structure to be shaped without rigid connection constraints.

Inventive Principle:
Principle #30Flexible shells and thin films

4Adaptability or versatility

If partition walls are added within honeycomb cells, then two types of resonators are formed with independent adjustable characteristics, but the device complexity increases

Engineering Contradiction:
Improveacoustic attenuation characteristicsVSAvoidpartition system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by varying the partition wall configurations within different zones of the honeycomb structure. Each zone can have partition walls positioned at different locations with different dimensions, allowing independent tuning of acoustic characteristics for each frequency range while using the same basic partition wall component, thus managing complexity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent achieves independent adjustable acoustic characteristics by changing geometric parameters of the partition walls (position, height, thickness) rather than changing the fundamental structure. This allows tuning of resonator properties through parameter variation of simple partition elements, maintaining device simplicity while achieving high adaptability.

Inventive Principle:
Principle #35Parameter changes

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

Facilitates easier installation and maintenance, reduces structural complexity, and enhances adjustable acoustic attenuation capabilities, enabling effective sound wave absorption across a broader frequency range.

Implementation Method 1

a first Helmholtz type resonator at the level of the cells of the first alveolar structure 12, adapted to attenuate low frequency sound waves

Methodology Applied
Scientific EffectHelmholtz resonance: Helmholtz Resonance

Implementation Method 2

a second % wave type resonator at the level of the cells of the second alveolar structure 14, adapted to attenuate high frequency sound waves

Methodology Applied
Scientific EffectAcoustic resonance: Resonance

Implementation Method 3

an acoustic absorption structure 10 comprises first and second alveolar structures 12, 14 positioned between an acoustically resistive layer 16 in contact with a medium in which acoustic waves propagate and a reflective layer 18

Methodology Applied
Scientific EffectAcoustic absorption: Acoustic Absorption

Data Source

PatentEP4654182A1Sound absorption structure comprising at least one partitioning system positioned in at least one cell to form two types of resonators, method for manufacturing such a structure
Publication Date: 2025.11.26 AIRBUS (SAS)
  • EP4654182A1 patent drawingFigure 1~3
  • EP4654182A1 patent drawingFigure 4~6
  • EP4654182A1 patent drawingFigure 7~8

AI summary

The invention relates to a sound-absorbing structure comprising a honeycomb structure (52) which includes at least one cell (60, 60') delimited by at least one wall (58') and at least one partitioning system (62). The latter comprises at least one subassembly (64, 64') positioned within the cell (60, 60') and designed to divide it into at least two cavities, as well as at least one tab (78, 78') connected to the subassembly (64, 64') and having a hook shape (84) positioned astride one of the first and second end edges (58.1', 58.2') of the wall (58'). This tab (78, 78') facilitates the placement of each partitioning system (62) and its retention within the cell (60, 60'). The invention also relates to an aircraft comprising at least one such structure and a method for assembling such a structure.