Cabin Air Compressor Inlet Damping With Viscoelastic Constrained Layers

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Solution Overview

Problem

Existing aircraft cabin air compressor inlets generate high vibration and noise levels, leading to excessive noise and increased aircraft weight due to bulky and inefficient vibration and noise-control components that cannot withstand vibration frequencies and temperature ranges.

Innovation Solution

A damping mechanism using a viscoelastic material (VEM) layer coupled to a structural substrate with a constraining layer to apply shear force, reducing vibration and noise while maintaining lightweight and efficient performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If bulky vibration and noise-control components are used, then vibration and noise levels are reduced, but aircraft weight increases

Engineering Contradiction:
Improvevibration and noise levelsVSAvoidaircraft weight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The patent applies a thin-film damping treatment consisting of multiple layers (including viscoelastic damping layers and constraining layers) directly onto the compressor inlet housing. This flexible thin-film approach provides effective vibration and noise control without the bulk and weight of traditional vibration control components, directly resolving the contradiction between noise reduction and weight reduction.

Inventive Principle:
Principle #30Flexible shells and thin films

2Object-affected harmful factors

If traditional damping components are used, then vibration control is achieved, but they cannot withstand vibration frequencies and temperature ranges

Engineering Contradiction:
Improvevibration controlVSAvoidwithstand vibration frequencies and temperature ranges
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent employs a multi-layer composite damping structure comprising viscoelastic damping layers, constraining layers, and adhesive layers. This composite material system is specifically designed to withstand the extreme vibration frequencies and temperature ranges encountered in aircraft engine environments, overcoming the limitations of traditional single-material damping components.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent utilizes the temperature-dependent properties of viscoelastic materials, which change their damping characteristics across different temperature ranges. By selecting materials with appropriate transition temperatures and configuring multiple layers, the system adapts to maintain effective vibration control across the full operating temperature range of the aircraft engine.

Inventive Principle:
Principle #35Parameter changes

3Strength

If stiff vibration control components are used, then structural support is provided, but they are not configured to withstand vibration frequencies

Engineering Contradiction:
Improvestructural supportVSAvoidwithstand vibration frequencies
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies flexible thin-film damping treatments that can conform to and move with the structural components rather than rigidly constraining them. This flexible approach allows the damping treatment to effectively counteract vibration frequencies while maintaining compatibility with the underlying structural support, avoiding the problems of stiff components that cannot withstand vibration.

Inventive Principle:
Principle #30Flexible shells and thin films

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

Effectively dampens vibrations and noise in aircraft cabin air compressor inlets, balancing noise reduction with weight and efficiency, and adapting to various environmental conditions.

Implementation Method 1

a damping element including a viscoelastic material (VEM) layer coupleable to the structural substrate of the aircraft

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Implementation Method 2

the VEM layer configured to dampen a vibration of the structural substrate

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 3

a constraining layer coupled to the VEM layer, the constraining layer configured to apply a shear force to the VEM layer

Methodology Applied
Scientific EffectShear force: Shear Stress

Data Source

PatentEP3499082B1Methods and systems for damping a cabin air compressor inlet
Publication Date: 2025.08.06 THE BOEING CO
  • EP3499082B1 patent drawingFigure 1
  • EP3499082B1 patent drawingFigure 2
  • EP3499082B1 patent drawingFigure 3

AI summary

A panel (300) includes a structural substrate (310) and a damping element (320) including a viscoelastic material (VEM) layer (330) coupleable to the structural substrate of the aircraft, and a constraining layer (340) coupled to the VEM layer. The VEM layer is configured to dampen a vibration of the structural substrate. The constraining layer is configured to apply a shear force to the VEM layer.