Elastic Metasurface Acoustic Shield for Vibration Isolation
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Solution Overview
Problem
Current vibration isolation systems are often bulky and heavy, and they have limited success in reducing or eliminating acoustic vibrations, particularly in engineered systems and habitable spaces.
Innovation Solution
The use of a metasurface-based acoustic shield with locally resonant units that create extreme phase gradients, implementing a generalized Snell's law to achieve total internal reflection and block vibrational waves across interfaces, forming a subwavelength sound-hard barrier that attenuates vibrational waves regardless of the angle of incidence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive vibration isolation materials and mechanical linkages are used to absorb and damp mechanical waves, then vibration isolation is achieved, but the system becomes bulky and adds significant weight and volume
Solution Approach 1:
The patent changes the fundamental parameters of the isolation system by transitioning from bulk materials to metasurface structures with engineered phase gradients. The phase gradient parameter dφ/dx is specifically controlled to achieve total internal reflection, enabling thin-profile isolation structures that maintain effectiveness without the bulk weight of traditional materials
Solution Approach 2:
The patent replaces traditional mechanical vibration isolation systems with an acoustic metasurface approach that uses phase-modulated interfaces. Instead of relying on mechanical damping materials, the system uses controlled phase gradients at interfaces to reflect vibrational waves, substituting a physics-based wave control mechanism for bulk mechanical absorption
2Reliability
If traditional vibration isolation systems are deployed to reduce acoustic vibrations, then some vibration reduction is achieved, but the success is limited in many applications
Solution Approach 1:
The patent applies local quality by creating spatially varying phase gradients at different interfaces. Each interface has a specifically tailored phase gradient dφ/dx that is adapted to the local requirements of the application, allowing the same metasurface structure to be optimized for different frequency ranges and vibration scenarios through localized parameter adjustment
Solution Approach 2:
The patent segments the vibration isolation function into multiple independent interfaces, each with its own phase gradient control. This segmentation allows the system to handle different vibration modes and frequency ranges independently, improving overall adaptability across diverse applications by addressing specific vibration problems at each interface
3Reliability
If bulk vibration isolation materials are used to block vibrational waves, then vibration attenuation is achieved, but the device complexity and volume increase significantly
Solution Approach 1:
The patent achieves high attenuation in a thin profile by changing from material-based absorption to parameter-based wave control. By precisely controlling the phase gradient parameter dφ/dx at each interface, the system achieves total internal reflection of vibrational waves without requiring the volume of bulk absorption materials
Solution Approach 2:
The patent transitions from three-dimensional bulk material isolation to two-dimensional interface-based phase modulation. The vibration isolation function is achieved at the interface plane rather than through volumetric materials, reducing the problem from a 3D material selection issue to a 2D phase gradient design problem, thereby minimizing the required volume
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 approach provides effective vibration isolation by substantially attenuating vibrational waves within a specific frequency band, acting as a compact and efficient sound-hard barrier that can significantly reduce or eliminate unwanted mechanical energy transmission to sensitive devices.
Implementation Method 1
a first locally resonant unit embedded along the first interface, the first locally resonant unit controlling a first phase gradient
Implementation Method 2
implementing a generalized Snell's law to achieve total internal reflection and block vibrational waves
Implementation Method 3
Active vibration isolation involves sensors and actuators that produce disruptive interference that cancels-out incoming vibration
Implementation Method 4
Passive vibration isolation makes use of materials and mechanical linkages that absorb and damp these mechanical waves
Data Source
AI summary
An acoustic shield for protecting a vibrational sensitive device includes a first unit cell and a second unit cell. The first unit cell includes a first locally resonant unit. The first locally resonant unit controls a first phase gradient and the first unit cell includes a first surface. The second unit cell includes a second surface proximate to the first surface. The second unit cell includes a second locally resonant unit embedded along the second interface. The second locally resonant unit controls a second phase gradient. The first phase gradient is different from the second phase gradient. The first unit cell and the second unit cell comprise a super cell. The acoustic shield is configured such that a vibrational wave from a first side of the super cell to a second side of the super cell is substantially attenuated.