Acoustic Septum Caps with Variable Depth Control

Solution Overview

Problem

Existing acoustic structures with honeycomb cells require multiple adhesive applications to achieve multiple degrees of acoustic freedom, leading to increased weight and potential alteration of physical properties, as well as difficulties in inserting septum caps due to adhesive buildup.

Innovation Solution

A set of planar acoustic inserts with varying septum depth control portions are used, allowing for septum portions to be located at different depths within honeycomb cells while the anchoring portions are bonded at the same depth using a single adhesive application, forming an acoustic structure with multiple degrees of freedom.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple adhesive applications are used to achieve multiple degrees of acoustic freedom, then acoustic performance is improved, but weight increases and manufacturing complexity increases

Engineering Contradiction:

Improveacoustic damping propertiesVSAvoidweight

Core Design Contradiction:

Adaptability or versatilityVSWeight of stationary object

Solution Approach 1:

The acoustic insert is segmented into distinct functional zones: an anchoring zone with adhesive application area at a first depth, and a damping zone with acoustic damping material at a second depth. This segmentation allows each zone to perform its specific function independently, enabling multiple acoustic degrees of freedom while using only a single adhesive application, thus avoiding the weight increase associated with multiple adhesive layers.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If multiple adhesive applications are used to achieve multiple degrees of acoustic freedom, then acoustic performance is improved, but device complexity increases

Engineering Contradiction:

Improveacoustic damping propertiesVSAvoidmanufacturing complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The acoustic insert is segmented into distinct functional zones: an anchoring zone with adhesive application area at a first depth, and a damping zone with acoustic damping material at a second depth. This segmentation allows each zone to perform its specific function independently, enabling multiple acoustic degrees of freedom while using only a single adhesive application, thus avoiding the weight increase associated with multiple adhesive layers.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The acoustic damping material is pre-positioned within the insert at the second depth before the insert is installed into the honeycomb cell. This preliminary positioning of the damping material eliminates the need for subsequent adhesive applications at different depths, simplifying the manufacturing process while maintaining multiple acoustic degrees of freedom.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If multiple adhesive applications are used to achieve multiple degrees of acoustic freedom, then acoustic performance is improved, but adhesive buildup occurs causing insertion difficulties

Engineering Contradiction:

Improveacoustic damping propertiesVSAvoidinsertion difficulty

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The acoustic damping material is pre-positioned within the insert at the second depth before the insert is installed into the honeycomb cell. This preliminary positioning of the damping material eliminates the need for subsequent adhesive applications at different depths, simplifying the manufacturing process while maintaining multiple acoustic degrees of freedom.

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 approach reduces noise attenuation complexity and weight, while maintaining the structural integrity and acoustic performance of the honeycomb, by enabling multiple acoustic damping properties with a single adhesive dip, thus enhancing the efficiency of noise reduction in sources like aircraft engines.

Implementation Method 1

acoustic damping structures (acoustic treatments) to the structure of the noise source

Methodology Applied

Scientific EffectAcoustic damping: Damping

Implementation Method 2

acoustic resonators that contain relatively thin acoustic materials or grids that have millions of holes that create acoustic impedance to the sound energy

Methodology Applied

Scientific EffectAcoustic resonance: Resonance

Data Source

PatentEP3295455B1Acoustic structures with multiple degrees of freedom

Publication Date: 2022.06.08 HEXCEL CORP

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AI summary

An acoustic structure having multiple degrees of acoustic freedom for reducing noise generated from a source. Acoustic septum caps, which are an integral part of the acoustic structure, include depth control portions that can be varied in width so that the septum portions of different septum caps can be located at different depths within the acoustic structure to provide an acoustic structure having multiple degrees of acoustic freedom even though the acoustic septum caps are anchored at the same depth within the structure.