Carbon Nanotube Composite Layer for Vibration Abatement
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Solution Overview
Problem
Conventional composite structures used in aerospace and vehicles face challenges in reducing noise transmission while maintaining strength, weight, and cost efficiency, and also require additional measures for thermal and electrical conductivity.
Innovation Solution
A composite layer comprising an elastomeric polymer matrix with dispersed carbon nano tubes is used to convert bending waves into shear waves, reducing noise radiation and enhancing thermal and electrical conductivities, thereby addressing the challenges of noise reduction and conductivity without increasing weight or complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional composite panels use light weight materials such as graphite-epoxy or aluminum face sheets with honeycomb core, then weight is reduced and strength is improved, but acoustic radiation efficiency increases because transverse and shear wave speeds exceed the speed of sound in air
Solution Approach 1:
The patent applies composite materials by integrating a viscoelastic damping layer between the face sheets and honeycomb core of the composite panel. This multi-layer composite structure combines the lightweight properties of graphite-epoxy or aluminum face sheets with the acoustic damping properties of the viscoelastic material, achieving both weight reduction and noise control simultaneously
Solution Approach 2:
The patent changes the physical parameters of the composite panel by introducing a viscoelastic layer with specific loss factors (tan δ) ranging from 0.05 to 0.50. This material parameter selection optimizes the conversion of supersonic bending waves to subsonic shear waves, reducing acoustic radiation while maintaining the structural integrity and lightweight characteristics of the original composite panel
2Object-generated harmful factors
If damping material or noise control material is added to the composite panel to provide sound and vibrational energy absorption, then acoustic radiation is reduced, but weight, cost, and complexity increase
Solution Approach 1:
The patent employs a thin viscoelastic damping layer (0.5mm to 5mm thick) as a flexible intermediate structure between the rigid face sheets and honeycomb core. This thin film approach provides effective acoustic damping without adding significant weight, unlike traditional bulky damping tiles or fiberglass blankets that require manual installation and add considerable mass
Solution Approach 2:
The patent merges the structural core (honeycomb) with the damping function by sandwiching the viscoelastic material within the composite panel structure itself, between the face sheets and core. This integration eliminates the need for separate damping treatments and reduces overall system complexity, while the lightweight nature of the viscoelastic layer avoids significant weight penalties compared to conventional noise control materials
3Object-generated harmful factors
If conventional composite structures use non-conductive elements such as damping material, fiberglass blanket, and acoustic foam, then noise control is achieved, but thermal and electrical conductivities deteriorate requiring extensive additional measures
Solution Approach 1:
The patent changes the electrical and thermal conductivity parameters of the composite panel by replacing traditional non-conductive damping materials with a viscoelastic layer that can be formulated with conductive fillers or carbon-based materials. This allows the damping layer to simultaneously provide acoustic damping and maintain acceptable electrical conductivity for grounding and static dissipation requirements in aerospace applications
Solution Approach 2:
The patent uses composite materials within the viscoelastic damping layer by incorporating conductive particles, fibers, or carbon nanotubes into the polymer matrix. This creates a multi-functional composite damping material that provides both acoustic energy absorption and electrical/thermal conduction pathways, eliminating the need for separate metallic wire mesh or grounding layers typically required with conventional non-conductive damping 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
The composite layer significantly reduces acoustic radiation by converting supersonic bending waves into sub-sonic shear waves, improving energy transmission loss by 10-15 dB and enhancing thermal and electrical conductivities, thus providing a lightweight, cost-effective solution for noise abatement and conductivity.
Implementation Method 1
converting supersonic bending waves into sub-sonic shear waves
Implementation Method 2
enhancing thermal and electrical conductivities
Implementation Method 3
enhancing thermal and electrical conductivities
Data Source
AI summary
Methods for vibration and acoustic abatement. The methods comprise providing a substrate with a composite layer deposited thereon, the substrate receiving a vibration energy sufficient to provide at least one bending wave therein, and converting at least a portion of the vibration energy sufficient to cause the at least one bending wave to at least one shear wave in at least a portion of the composite layer. The composite layer comprises an elastomeric polymer matrix comprising carbon nano tubes dispersed or distributed therein. Articles with the composite layer comprising carbon nano tubes disposed thereon are also disclosed and described.