Monopole-Dipole Scatterers for Complete Flexural Wave Absorption
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Solution Overview
Problem
Traditional sound absorption methods fail to effectively reduce flexural waves, which are the root cause of airborne noise, as they primarily target radiated sound and vibration rather than the waves themselves.
Innovation Solution
A system utilizing a pair of scatterers, including a monopole and a dipole scatterer, mounted at the same location on a structure, with resonant frequencies matching the flexural wave, each absorbing 50% of the wave energy, resulting in a combined 100% absorption when both are used.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If traditional sound absorbing materials are installed to reduce airborne noise, then airborne noise is reduced, but the flexural wave (root cause) is not significantly impacted
Solution Approach 1:
The patent introduces monopole and dipole scatterers as intermediary elements that couple the airborne acoustic field with the structural flexural wave field. These scatterers act as mediators that transfer energy from the flexural wave to the acoustic field, enabling direct targeting of the root cause rather than just the symptom
Solution Approach 2:
The patent replaces traditional mechanical damping approaches with acoustic resonance-based scatterers. Instead of using mechanical damping materials applied to the structure, the system uses acoustic scatterers that exploit resonance phenomena to convert flexural wave energy into acoustic energy that can be absorbed
2Loss of energy
If damping materials are applied to reduce vibration, then some vibration reduction is achieved, but complete flexural wave absorption is not realized
Solution Approach 1:
The patent employs resonance-based mechanical vibration principles where monopole and dipole scatterers are tuned to resonate at specific frequencies matching the flexural wave. This resonant coupling enables efficient energy transfer and absorption that surpasses conventional damping materials
Solution Approach 2:
The patent changes the approach from passive damping to active resonance by tuning the scatterer parameters (mass, stiffness, damping) to match the flexural wave frequency characteristics. This parameter matching enables resonant absorption rather than broadband damping
3Reliability
If high-mass structures are added to prevent vibration passage, then vibration transmission is reduced, but the system becomes more complex and heavy
Solution Approach 1:
The patent changes from mass-based vibration isolation to resonance-based absorption. By adjusting the scatterer parameters (mass, stiffness, damping coefficients) to match the flexural wave frequency, effective vibration control is achieved without adding significant mass to the structure
Solution Approach 2:
The patent uses resonant vibration of the scatterers to achieve vibration isolation effects. The monopole and dipole scatterers resonate at frequencies matching the flexural wave, creating strong coupling that prevents vibration transmission without requiring high mass
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 system achieves complete absorption of flexural waves by leveraging the resonant properties of monopole and dipole scatterers, effectively reducing structural vibrations and associated noise.
Implementation Method 1
The monopole scatterer and the dipole scatterer may have resonant frequencies similar to the flexural wave acting upon the structure
Implementation Method 2
Flexural waves, sometimes called bending waves, deform the structure transversely as they propagate
Data Source
AI summary
Disclosed are systems and devices for absorbing flexural waves. In one example, a pair of scatterers for absorbing a flexural wave acting on a structure includes a monopole scatterer and a dipole scatterer configured to be mounted to the structure at the same location.