Corrugated Acoustic Panel Stiffeners for Edge Loss Reduction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing acoustic panels in gas turbine engines, particularly those with honeycomb cores, suffer from inefficiencies in noise attenuation due to manufacturing processes that result in edge losses, leading to reduced acoustic performance in areas like blocker doors.

Innovation Solution

The use of a corrugated stiffening member in acoustic panels, formed through methods such as stamp forming, to enhance noise attenuation by optimizing the space between the top sheet and backskin, thereby increasing the effective acoustic area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a honeycomb core is used in acoustic panels, then structural support is provided, but manufacturing processes result in edge losses that reduce acoustic performance

Engineering Contradiction:
Improvestructural supportVSAvoidacoustic performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The panel is segmented into distinct functional zones: a honeycomb core region for structural support and a corrugated stiffening member region for acoustic performance. This segmentation allows each zone to be optimized for its specific function without compromising the other, as the corrugated member extends from the edge toward the center to provide acoustic benefits while the honeycomb core maintains structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the panel are given different structural qualities: the honeycomb core provides rigid structural support in the center, while the corrugated stiffening member provides acoustic absorption and edge reinforcement at the periphery. This local differentiation of material properties and structural characteristics allows simultaneous optimization of both structural support and acoustic performance in different locations.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If traditional acoustic panel construction is used, then manufacturing is straightforward, but noise attenuation efficiency is reduced due to edge losses

Engineering Contradiction:
Improvemanufacturing straightforwardnessVSAvoidnoise attenuation efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The corrugated stiffening member introduces a third dimension to the panel structure by creating a curved, wave-like profile that extends from the edge toward the center. This dimensional change increases the effective acoustic path length and surface area without significantly complicating the manufacturing process, as the corrugated shape can be formed using standard molding or forming techniques applied during panel fabrication.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If the space between top sheet and backskin is maximized, then acoustic performance improves, but structural integrity may be compromised

Engineering Contradiction:
Improveacoustic performanceVSAvoidstructural integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The corrugated stiffening member introduces curvature into the panel structure, creating a wave-like profile between the top sheet and backskin. This curvature increases the acoustic path length and effective surface area for noise attenuation while the corrugated shape itself provides structural rigidity. The curved geometry distributes stresses more effectively than a flat structure, maintaining structural integrity even with increased spacing between the sheets.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 corrugated stiffening member enhances noise attenuation by up to 5-10% in areas like blocker doors, improving acoustic efficiency and manufacturing ease while maintaining structural integrity.

Implementation Method 1

The corrugated stiffening member enhances noise attenuation by up to 5-10% in areas like blocker doors, improving acoustic efficiency

Methodology Applied
Scientific EffectAcoustic absorption: Acoustic Absorption

Data Source

PatentEP4144650B1Corrugated acoustic stiffening devices and methods
Publication Date: 2025.11.12 ROHR INC
  • EP4144650B1 patent drawingFigure 1
  • EP4144650B1 patent drawingFigure 2
  • EP4144650B1 patent drawingFigure 3A~3B

AI summary

A method for forming a fiber-reinforced thermoplastic acoustic panel (300) may comprise: stacking plies of thermoplastic composite sheets to a first thickness to form a top sheet (320); stacking plies of thermoplastic composite sheets to a second thickness to form a backskin (330); staking plies of thermoplastic composite sheets to a third thickness to form a stiffening member (312); forming the top sheet (320) in a first contour; forming the backskin (330) in a second contour, the second contour being different from the first contour; forming the stiffening member (312) comprising a shape having a plurality of peaks (314) and troughs (316); bonding the stiffening member (312) to the top sheet (320) and the backskin (330); and perforating the top sheet (320).