Acoustic Attenuation Panel Manufacturing via Integrated Molding

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Solution Overview

Problem

The manufacturing of ceramic matrix composite (CMC) acoustic attenuation panels for aircraft turbojet engines is complex and costly, requiring separate production and assembly of honeycomb structures and skins, which complicates the process and increases material usage.

Innovation Solution

A method involving draping fibrous reinforcements in a mold, depositing fugitive blocks to define spaces, and infiltrating with a ceramic precursor medium, followed by sintering, which integrates the cellular core and skins simultaneously, eliminating the need for pre-manufactured honeycomb structures and allowing for customizable acoustic properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If separate production and assembly of honeycomb structures and skins is used, then manufacturing precision can be maintained for each component, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvemanufacturing process complexityVSAvoidcomponent fabrication precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent merges the separate manufacturing processes of honeycomb structures and skins into a single integrated molding process. The mold cavity is designed to form both the cellular core and the acoustic attenuation skins simultaneously in one operation, eliminating the need for separate production and assembly steps while maintaining manufacturing precision through controlled molding parameters.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The molding process is designed to perform multiple functions simultaneously: it forms the honeycomb cellular structure, creates the acoustic attenuation skins with specific geometries, and integrates connecting radii for structural attachment. This multi-functional approach reduces device complexity while maintaining the precision needed for each specific component.

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

2Productivity

If separate production and assembly of honeycomb structures and skins is used, then each component can be optimized independently, but manufacturing time and material usage increase

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidmaterial usage
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

By combining the formation of honeycomb structures and skins into a single molding operation, the patent eliminates the need for separate manufacturing cycles and assembly steps. This integration significantly improves productivity by producing complete acoustic attenuation panels in one process while reducing material waste associated with multiple handling and assembly operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The molding process performs preliminary actions by pre-forming the connecting radii and integration features during the initial shaping of the panel. This eliminates the need for subsequent assembly operations and reduces material usage that would otherwise be required for separate components and joining materials.

Inventive Principle:
Principle #10Preliminary action

3Weight of moving object

If traditional acoustic attenuation structures are used, then acoustic performance can be achieved, but weight of the panel increases

Engineering Contradiction:
Improvepanel weightVSAvoidacoustic noise
Core Design Contradiction:
Weight of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent employs composite material structures where the honeycomb cellular core is integrated with acoustic attenuation skins made of suitable materials. This composite approach provides effective acoustic noise attenuation while maintaining low weight, as the cellular structure and thin skins achieve acoustic performance without requiring heavy monolithic materials.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The honeycomb cellular structure serves as a porous material that provides acoustic attenuation through its cell structure. The interconnected cells and walls create acoustic pathways that absorb and dissipate noise energy while maintaining a lightweight construction, eliminating the need for heavier traditional acoustic materials.

Inventive Principle:
Principle #31Porous materials

4Temperature

If ceramic matrix composite materials are used, then high-temperature resistance is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvehigh-temperature resistanceVSAvoidmanufacturing process complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent combines the formation of ceramic matrix composite structures with integrated honeycomb and skin features in a single molding process. This integration simplifies manufacturing by eliminating multiple separate steps that would otherwise be required to handle the complexity of CMC material processing, while still achieving the desired high-temperature resistance.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The molding process performs preliminary shaping and integration of CMC structures before final sintering or heat treatment. This preliminary action reduces manufacturing complexity by establishing the complex geometry and material distribution early, allowing subsequent thermal processing to simply consolidate the structure rather than create it.

Inventive Principle:
Principle #10Preliminary action

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 method simplifies the manufacturing process, reduces material usage, and enhances the acoustic attenuation capabilities of the panels by allowing for in-situ formation of the cellular core and skins, resulting in a lightweight, high-temperature-resistant acoustic panel with improved acoustic performance.

Implementation Method 1

infiltrate, by means of a liquid medium, the precursor of the ceramic phase through said skins and into said at least one space separating said blocks of fugitive material

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

remove the liquid medium by evaporation or polymerization

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

sinter the assembly at a temperature that allows the ceramic oxide material to consolidate and the fugitive material to be removed

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP3325270B1Process for manufacturing an acoustic attenuation panel from a composite material with an oxide ceramic matrix
Publication Date: 2019.05.15 SAFRAN NACELLES
  • EP3325270B1 patent drawingFigure 1
  • EP3325270B1 patent drawingFigure 2~4
  • EP3325270B1 patent drawingFigure 5~8

AI summary

The invention relates to a method for producing an acoustic attenuation panel from a composite material with a ceramic oxide matrix, comprising the following steps: a) draping a plurality of plies in a mould, said plies consisting of fibrous reinforcements comprising fibres of a ceramic material defining a first skin (19) of the acoustic attenuation panel; b) depositing a plurality of blocks (21; 21a, 21b) of a first so-called fugitive material on the first skin, such as to define at least one space (E) between two of the blocks, the corners of the blocks (21; 21a, 21b) being rounded; c) draping a plurality of plies on the surface formed by the blocks, said plies consisting of fibrous reinforcements comprising fibres of a ceramic material, such as to define a second skin (27) of the acoustic attenuation panel; d) using the corners of the blocks (21; 21a; 21b) to define radii for connecting the first and second skins with walls of the honeycomb core of the acoustic panel; e) using a liquid medium to infiltrate the skins (19, 27) and the at least one space (E) separating the blocks of fugitive material with the precursor of the ceramic phase; f) removing the liquid medium by means of evaporation or polymerisation; g) sintering the assembly at a temperature allowing consolidation of the ceramic oxide material and removal of the fugitive material.