Compound Acoustic Black Hole Damper for Low-Power Vibration Control
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Solution Overview
Problem
Conventional structural dampers incorporating acoustic black holes (ABHs) face sub-optimal damping effects, require powerful actuators that can cause damage, and degrade over time due to exposure to contaminants and lack of support, limiting their broad application.
Innovation Solution
A structural damper comprising a first and second ABH with an actuator applying a controlled actuating force, optionally with sensors and controllers to manage vibration, flexural waves, and acoustic radiation, enhancing damping performance and reducing actuator size and degradation risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional structural dampers with ABHs are used, then damping effect is provided, but the damping effect is sub-optimal and powerful actuators are required
Solution Approach 1:
The single ABH structure is segmented into a compound ABH comprising a first ABH and a second ABH positioned at different locations. This segmentation allows the system to achieve superior damping effectiveness by targeting multiple vibration modes simultaneously, reducing the power requirements of individual actuators while maintaining overall damping performance.
Solution Approach 2:
The invention transitions from a single-point damping approach to a multi-dimensional approach by positioning actuators at different spatial locations (first ABH and second ABH). This dimensional expansion enables more comprehensive vibration control across different modes and frequencies, improving damping effectiveness without requiring excessive actuator power at any single location.
2Reliability
If powerful actuators are used to provide sufficient damping, then damping performance is improved, but damage or deterioration of ABHs may occur
Solution Approach 1:
By segmenting the damping function across multiple ABHs and actuators, the force requirements for each actuator are reduced. This prevents any single actuator from applying excessive force that could damage the ABH structure, while the combined effect of multiple actuators maintains overall damping performance.
Solution Approach 2:
Each actuator in the compound ABH system operates with optimized local force application tailored to specific vibration modes. This localized quality control ensures that actuators apply only the necessary force at specific locations, avoiding excessive forces that could compromise ABH structural integrity while maintaining effective damping.
3Productivity
If structural dampers are exposed to environment, then damping function is provided, but performance degrades over time due to contaminants and lack of support
Solution Approach 1:
The ABHs are nested within a support structure that provides protection from environmental contaminants. This nested configuration allows the damping function to be maintained while shielding the sensitive ABH regions and actuators from degradation, ensuring long-term performance stability without compromising damping effectiveness.
Solution Approach 2:
The support structure provides beforehand protection against environmental degradation before contaminants can damage the ABHs and actuators. This preventive cushioning approach maintains the damping function over time by protecting the components from harmful environmental exposure, ensuring reliable long-term operation.
4Reliability
If ABH thickness reduces to zero for ideal damping, then wave reflection is eliminated, but structural strength is compromised
Solution Approach 1:
The ABH structure is segmented into multiple regions (first ABH and second ABH) with different thickness profiles. This segmentation allows each region to be optimized for specific functions: some regions can achieve near-zero thickness for ideal wave attenuation, while other regions maintain sufficient thickness for structural strength, achieving both goals simultaneously through distributed design.
Solution Approach 2:
Different regions of the compound ABH structure have locally optimized thickness characteristics. The first ABH and second ABH can have different thickness profiles tailored to their specific locations and functions, allowing zero-thickness regions for optimal damping where structurally permissible, and thicker regions where structural strength is required, achieving both wave attenuation and structural integrity.
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 solution provides improved damping effectiveness, reduces actuator size, and extends the structural damper's lifespan by protecting the actuator and ABHs from environmental degradation, enabling broader application in various structures.
Implementation Method 1
The acoustic black hole effect is typically achieved by introducing a power law taper into a beam or plate that changes the thickness over a set distance. This change in thickness profile causes the flexural waves propagating along the direction of the ABH to decrease in wave speed.
Implementation Method 2
The flexural wave speed cf (x), decreases as the taper height decreases as: cf (x) = √(2E/ρs) × h(x)^(n-2)/2 × ω^1/2
Implementation Method 3
an actuator provided in contact with the first ABH and second ABH, wherein the actuator is configured to apply an actuating force to the first ABH and the second ABH
Implementation Method 4
it is often necessary to design a product that is both lightweight and a low noise structure. However, this results in a conflict between reducing the weight and increasing the sound radiation from the structure.
Data Source
AI summary
According to the present disclosure, there is provided a structural damper for providing damping of a primary structure, the structural damper comprising: a first acoustic black hole, ABH; a second ABH; and an actuator provided in contact with the first ABH and second ABH, wherein the actuator is configured to apply an actuating force to the first ABH and the second ABH.