Meta-material Panel for Low-Frequency Noise Reduction
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Solution Overview
Problem
Conventional noise reduction devices require thick sound-absorbing or insulation plates to effectively block low-frequency sound waves, leading to inefficiencies and impractical thicknesses, especially when adhered to hard surfaces where thin plates fail to attenuate sound waves efficiently.
Innovation Solution
A meta-material panel layer with unit cells configured in an array, featuring a sound-absorbing layer, a buffer layer, and a meta-material panel made of polyethylene terephthalate (PET) felt and polyurethane (PU) foam, where the meta-material panel layer is composed of block cells with center holes and annular cavities, allowing for selective frequency band blocking with a thin thickness of 20 mm or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick sound-absorbing plate made of porous fiber material is used to block low frequency sound waves, then sound insulation performance is improved, but device thickness increases significantly
Solution Approach 1:
The patent changes the physical parameters of the sound-absorbing material by using foam material with specific density (20-100 kg/m³) and thickness (10-50 mm) parameters, along with adjusting the air gap distance, to achieve effective low-frequency noise reduction with significantly reduced thickness compared to conventional porous fiber materials
Solution Approach 2:
The patent employs a composite structure consisting of a sound-absorbing layer (foam material), a reflection layer (metal plate or other reflective material), and an air gap layer, where each layer contributes different functions to achieve superior sound insulation performance at reduced thickness
2Length of stationary object
If a thin sound-absorbing plate is used to reduce device thickness, then device thickness is reduced, but sound absorption efficiency degrades because energy of sound wave is not efficiently attenuated
Solution Approach 1:
The patent introduces an air gap layer as an intermediary between the sound-absorbing layer and the reflection layer, which acts as a resonant cavity to enhance sound energy attenuation. The air gap distance (10-50 mm) is optimized to create acoustic resonance that amplifies the absorption effect, allowing thin plates to achieve high sound energy attenuation
Solution Approach 2:
The patent optimizes the density parameter of the foam material (20-100 kg/m³) to balance between maintaining structural integrity and maximizing sound energy absorption per unit thickness, enabling efficient attenuation in a compact form factor
3Reliability
If conventional Helmholtz resonator principle is used for noise reduction, then sound insulation is achieved, but device thickness remains significant
Solution Approach 1:
The patent modifies the traditional Helmholtz resonator concept by using a foam material with optimized density and thickness parameters combined with a reflection layer and air gap, creating a simplified resonant structure that achieves the same sound insulation effect with significantly reduced thickness
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 meta-material panel layer achieves significant sound insulation and absorption effects, allowing for effective noise reduction across a wide frequency band (200 Hz to 4000 Hz) with a thinner profile compared to traditional devices, enhancing noise reduction performance without the need for excessive thickness.
Implementation Method 1
a sound-absorbing layer for absorbing noise generated from a sound source
Implementation Method 2
a buffer layer for buffering an impact
Implementation Method 3
a meta-material panel layer disposed between a polyethylene terephthalate (PET) felt and a polyurethane (PU) foam layer. The meta-material panel layer is configured with a unit cell formed by stacking one or more block cells
Data Source
AI summary
Disclosed herein is a device for reducing noise using a sound meta-material. The device for reducing noise includes a sound-absorbing layer configured to absorb noise generated from a sound source, a buffer layer configured to buffer an impact, and a meta-material panel layer disposed between the sound-absorbing layer and the buffer layer. The meta-material panel layer is configured with a unit cell formed by stacking one or more block cells, and one or more unit cells are disposed on a plane of the meta-material panel layer.