Sandwich Component Vibration Damping with Porous Protective Layer

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Solution Overview

Problem

Sandwich components used in applications like aircraft cabins suffer from low vibration absorptivity, leading to increased noise levels due to the transmission of vibrations, and existing vibration damping solutions can degrade over time, affecting mechanical properties.

Innovation Solution

Incorporating viscoelastic layers between the core and cover layers, with additional porous layers attached to prevent penetration of core layer edges, maintaining damping effectiveness and minimizing weight increase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If vibration damping layers comprising viscoelastic material are included in sandwich structures, then vibration absorptivity is improved, but the layers may be penetrated by core layer edges during manufacturing and use, causing degradation of damping performance over time

Engineering Contradiction:
Improvevibration transmissionVSAvoidstability of vibration absorptivity
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

A porous layer with higher compressive strength is introduced as an intermediary between the core layer and the viscoelastic damping layer. This porous layer acts as a protective mediator that prevents the sharp edges of the core layer cells from penetrating into the viscoelastic material, thereby maintaining the integrity and long-term effectiveness of the damping layer without compromising vibration absorption performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The porous layer is positioned in advance between the core layer and viscoelastic damping layer to provide preliminary protection. This prior cushioning structure prevents direct contact and potential penetration between the core edges and the damping material during both manufacturing compression and subsequent service loading, ensuring stable damping performance from the outset.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If porous layers with higher compressive strength are added to protect viscoelastic layers, then penetration prevention is improved, but device complexity and manufacturing steps increase

Engineering Contradiction:
Improveprotection of viscoelastic layerVSAvoidnumber of layers
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A porous layer made of compressible porous material is used to provide protection against penetration. The porous structure allows this layer to be compressible enough to accommodate manufacturing processes while maintaining sufficient compressive strength to prevent edge penetration into the viscoelastic damping layer, balancing protection needs with manufacturing feasibility.

Inventive Principle:
Principle #31Porous materials

3Reliability

If multiple layers are added to improve vibration damping stability, then damping effectiveness is maintained, but weight increases

Engineering Contradiction:
Improvestability of vibration absorptivityVSAvoidweight of sandwich component
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The porous protective layer is applied locally only at the interfaces between the core layer and viscoelastic damping layer, rather than throughout the entire sandwich structure. This localized approach provides targeted protection where penetration risks exist while minimizing the overall weight increase associated with adding protective layers.

Inventive Principle:
Principle #3Local quality

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 solution provides stable high vibration absorptivity over time without compromising mechanical properties, effectively reducing noise transmission and maintaining structural integrity.

Implementation Method 1

vibration damping layers typically comprising a viscoelastic material, such as an elastomeric material, have been included in the sandwich structures

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Implementation Method 2

Such vibration damping layers convert a portion of the vibration energy into heat

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Data Source

PatentEP2636514B1Sandwich component
Publication Date: 2020.04.29 AIRBUS OPERATIONS GMBH
  • EP2636514B1 patent drawingFigure 1
  • EP2636514B1 patent drawingFigure 2
  • EP2636514B1 patent drawingFigure 3

AI summary

The present invention relates to sandwich component and a method for producing such sandwich component. In addition to a viscoelastic layer (8) disposed between a honeycomb-like core layer (2) and one of two cover layers (3) of the sandwich component (1, 1') a porous layer (9) is provided which is attached the viscoelastic layer (8) at the side of the viscoelastic layer (8) facing away from the cover layer (3) between which and the core layer (2) the viscoelastic layer (8) is disposed. The porous layer (9) has a higher compressive strength than the viscoelastic layer (8). The sandwich panel may be produced by forming a corresponding layered structure including the layers of the sandwich panel (1, 1') and subsequently applying heat and/or pressure to said layered structure in order to produce the sandwich component (1, 1').