Acoustic Panel Shape Memory Constrictions for Adaptive Noise Attenuation

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Solution Overview

Problem

Conventional acoustic panels for aircraft propulsion systems are ineffective at attenuating noise across a wide and variable spectrum of gas turbine engine operating states, as they are typically tuned for specific operating conditions.

Innovation Solution

An acoustic panel system utilizing shape memory materials and magnetic actuation to dynamically adjust the configuration of constrictions within a honeycomb core structure, allowing for adaptive noise attenuation across different frequency bands by altering the size and geometry of apertures between sub-chambers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If acoustic panels are tuned to attenuate noise at a particular gas turbine engine operating state, then noise attenuation efficiency is improved at that specific operating state, but noise attenuation effectiveness deteriorates at other operating states

Engineering Contradiction:
Improvenoise attenuation efficiencyVSAvoidnoise attenuation effectiveness across operating states
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The acoustic panel employs shape memory material constrictions that can dynamically change their configuration between different states. These constrictions can be actuated to alter the chamber geometry, allowing the panel to adapt its acoustic properties to match different engine operating states, thereby maintaining effective noise attenuation across varying conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the physical parameters of the acoustic panel by using shape memory material to modify the constriction geometry. By actuating these constrictions, the panel can alter its resonant frequencies and acoustic impedance to optimize noise attenuation for different operating states, transforming a static structure into a tunable system

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If shape memory material constrictions are used to dynamically adjust chamber configuration, then adaptability across operating states is improved, but device complexity increases

Engineering Contradiction:
Improvenoise attenuation across operating statesVSAvoidacoustic panel structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention replaces complex mechanical actuation systems with a more elegant solution using shape memory materials. These materials inherently possess the ability to change shape in response to thermal or magnetic stimuli, eliminating the need for traditional motors, linkages, and control mechanisms while achieving the same adaptive functionality

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The acoustic panel integrates shape memory material with the structural components of the panel, creating a composite structure where the constriction elements are formed from shape memory alloy or polymer. This integration allows the material itself to provide both structural support and adaptive functionality, reducing overall system complexity

Inventive Principle:
Principle #40Composite materials

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

Enables efficient noise attenuation across a wide range of gas turbine engine operating states by dynamically tuning the acoustic panel's response to changing conditions, effectively reducing noise through phase reversal and destructive interference of sound waves.

Implementation Method 1

The first constriction includes a shape memory material configured to deform between the first configuration and the second configuration when subject to an input

Methodology Applied
Scientific EffectShape memory material deformation: Shape Memory Polymer

Implementation Method 2

The actuator is configured to remotely actuate deformation of the first constriction. The actuator may be configured as or otherwise include an electromagnet

Methodology Applied
Scientific EffectMagnetic actuation: Electromagnet

Implementation Method 3

effectively reducing noise through phase reversal and destructive interference of sound waves

Methodology Applied
Scientific EffectDestructive interference: Interference

Implementation Method 4

An aircraft propulsion system typically includes one or more acoustic panels for attenuating noise generated by a gas turbine engine

Methodology Applied
Scientific EffectAcoustic attenuation: Acoustic Absorption

Data Source

PatentEP4131252B1Acoustic panel with reconfigurable chamber constrictions
Publication Date: 2024.12.18 ROHR INC
  • EP4131252B1 patent drawingFigure 1
  • EP4131252B1 patent drawingFigure 2A~2B
  • EP4131252B1 patent drawingFigure 3A~3B

AI summary

An acoustic panel system (69) is provided that includes a perforated first skin (22), a second skin (23) and a core (24). The core (24) is connected to the perforated first skin (22) and the second skin (23). The core (24) includes a plurality of chambers (46) and a first constriction (52). Each of the chambers (46) extends vertically through the core (24) between the perforated first skin (22) and the second skin (23). The chambers (46) include a first chamber. The first constriction (52) is configured to divide the first chamber into a plurality of fluidly coupled sub-chambers (46A, 46B). The first constriction (52) is configured from or otherwise includes a shape memory material.