Active Membrane-Type Acoustic Metamaterial for Tunable Sound Attenuation
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Solution Overview
Problem
Existing sound attenuation panels can only attenuate a narrow band of frequencies and lack the ability to adjust their frequency range, limiting their effectiveness in real-life scenarios where sound attenuation needs may change.
Innovation Solution
The development of membrane-type acoustic metamaterials with an acoustically transparent planar rigid frame and flexible material divided into individual cells, each equipped with an electromagnetic or electrostatic response unit that can modify the resonant frequency by applying electric voltage or current, allowing for active control of sound attenuation across a broader frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single panel with fixed weights is used, then the structure is simple and easy to manufacture, but it can only attenuate a narrow band of frequencies and lacks adjustability
Solution Approach 1:
The patent applies the dynamics principle by transforming the static weight configuration into a dynamic, adjustable system. Electromagnetic actuators are integrated into each cell to enable real-time modification of the resonant frequency by adjusting the magnetic force applied to the weights. This allows the sound attenuation frequency to be dynamically tuned according to different noise control requirements, resolving the contradiction between fixed structure simplicity and frequency adaptability.
Solution Approach 2:
The patent implements parameter changes by modifying the resonant frequency parameter through electromagnetic actuation. By changing the magnetic force parameter applied to the weights, the resonant frequency of each cell can be adjusted, thereby changing the sound attenuation characteristics. This enables the panel to adapt to different frequency ranges without requiring physical reconfiguration, resolving the contradiction between structural simplicity and frequency versatility.
2Adaptability or versatility
If multiple panels with different weights are stacked to increase attenuation bandwidth, then the frequency coverage is improved, but the overall structure becomes more complex and heavier
Solution Approach 1:
The patent applies dynamics by enabling a single panel to dynamically adjust its attenuation characteristics through electromagnetic actuation. Instead of stacking multiple fixed panels, one adjustable panel can cover a broad frequency range by modifying the resonant frequency of its cells in real-time. This reduces the overall weight while maintaining or expanding the attenuation bandwidth, resolving the contradiction between bandwidth coverage and weight.
Solution Approach 2:
The patent implements multi-functionality by designing each cell to perform multiple functions: sound attenuation at different frequencies, and potential active noise cancellation. The electromagnetic actuators enable each cell to adapt its resonant frequency to match different target frequencies, making a single panel capable of replacing multiple specialized panels. This reduces the total weight and complexity while achieving broad frequency coverage.
3Adaptability or versatility
If multiple panels with different weights are stacked to increase attenuation bandwidth, then the frequency coverage is improved, but the device complexity increases
Solution Approach 1:
The patent applies dynamics by transforming the static multi-panel configuration into a dynamic single-panel system. Each cell in the panel is equipped with electromagnetic actuators that enable real-time adjustment of resonant frequency. This dynamic capability allows a single panel to achieve the same broad frequency coverage as multiple stacked panels, thereby reducing structural complexity while maintaining attenuation bandwidth.
Solution Approach 2:
The patent implements merging by combining the functions of multiple fixed panels into a single adjustable panel. The electromagnetic actuation system integrates the frequency-selection capability that previously required separate panels into a unified, controllable system. This consolidation reduces the number of components and simplifies the overall structure while maintaining or enhancing the attenuation bandwidth through active control.
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
This solution enables the active manipulation of sound waves, including phase modulation and switching, with tunable eigenfrequencies up to 70 Hz and significant sound transmission loss, enhancing the adaptability and effectiveness of sound attenuation panels in dynamic environments.
Implementation Method 1
Each cell has a weight fixed to the membrane. The planar geometry of each said individual cell, the flexibility of said flexible material and the weights establish a base resonant frequency of said sound attenuation. One or more of the cells having an electromagnetic or electrostatic response unit configured to modify the resonant frequency of the cell.
Implementation Method 2
One or more of the cells having an electromagnetic or electrostatic response unit configured to modify the resonant frequency of the cell.
Implementation Method 3
The planar geometry of each said individual cell, the flexibility of said flexible material and the weights establish a base resonant frequency of said sound attenuation.
Implementation Method 4
locally resonant sonic materials (LRSM) act as membrane-type acoustic metamaterials (MAMs). The MAMs are able to provide a shield or sound barrier against one or more particular frequency ranges as a sound attenuation panel.
Data Source
AI summary
Sound attenuation is performed using a sound attenuation panel using an electromagnetic or electrostatic response unit to modify resonance. The sound attenuation panel has an acoustically transparent planar, rigid frame divided into a plurality of individual cells configured for attenuating sound. In one configuration, each cell has a weight fixed to the membrane. The planar geometry of each said individual cell, the flexibility of the membrane, and the weight establish a base resonant frequency for sound attenuation. The electromagnetic or electrostatic response unit is configured to modify the resonant frequency of the cell.