Flextensional Piezoelectric Damper for Broad-Band Vibration Isolation
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Solution Overview
Problem
Existing vibration isolators face limitations in performance, adaptability, and robustness, particularly in efficiently damping vibrations across a wide frequency band, especially at low frequencies and in static resistance, with piezoelectric solutions being less robust and inefficient at low frequencies.
Innovation Solution
A passive vibration damping system using a flextensional structure with a piezoelectric stack and an elastic suspension, combined with a shunt to modify electrical stiffness, effectively transforming mechanical vibrations into electrical energy and dissipating energy for enhanced damping across a broad frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If piezoelectric suspensions are used to convert mechanical energy into electrical energy, then adaptability to operating conditions is improved, but robustness deteriorates and low-frequency damping efficiency is reduced
Solution Approach 1:
The invention combines piezoelectric elements with a flextensional structure made of elastic or flexible material to create a composite system. This composite approach allows the piezoelectric elements to provide adaptability while the flextensional structure provides mechanical robustness and low-frequency damping capability, resolving the contradiction between adaptability and robustness
Solution Approach 2:
The flextensional structure uses flexible walls that can deform under vibration to amplify mechanical motion and transfer it to the piezoelectric elements. This flexible structure maintains robustness while enabling the piezoelectric elements to function effectively across a broader frequency range including low frequencies
2Adaptability or versatility
If piezoelectric stacks are used in passive assemblies, then adaptability is improved, but low-frequency damping efficiency deteriorates due to relative rigidity
Solution Approach 1:
The flextensional structure is designed to resonate at low frequencies, using mechanical vibration principles to amplify low-frequency vibrations. This resonance amplification allows the piezoelectric elements to effectively convert low-frequency mechanical energy into electrical energy, improving low-frequency damping efficiency while maintaining adaptability
Solution Approach 2:
The invention introduces a geometric amplification mechanism where small deformations of the flextensional structure are amplified into larger displacements of the piezoelectric elements. This dimensional transformation enables effective low-frequency damping by converting subtle low-frequency vibrations into sufficient mechanical stress on the piezoelectric elements
3Reliability
If purely mechanical isolators are used to transform mechanical energy into thermal energy, then robustness is improved, but adaptability to operating conditions deteriorates
Solution Approach 1:
The invention replaces the purely mechanical energy dissipation mechanism with an electromechanical conversion system. The piezoelectric elements convert mechanical vibration energy into electrical energy, which is then dissipated through electrical resistance in a shunt circuit. This substitution provides adaptability through electrical control while maintaining the robustness of the mechanical flextensional structure
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 efficient vibration damping over a frequency range from 50 Hz to 20 KHz with attenuation of 40 dB/decade to 60 dB/decade from 500 Hz to 20 KHz, improving upon prior art by increasing robustness and adaptability while maintaining simplicity and cost-effectiveness.
Implementation Method 1
piezoelectric elements stacked along the first axis so as to form a piezoelectric stack, which piezoelectric stack is adapted to produce electrical energy when it is stressed
Implementation Method 2
a means for modifying the electrical stiffness of the piezoelectric stack, which means is a shunt connected to said piezoelectric stack so as to dissipate all or part of the electrical energy produced by the stress applied to said piezoelectric stack
Implementation Method 3
at least one of the fasteners preferably integrates an elastic suspension
Data Source
AI summary
A system for passive damping of mechanical vibrations generated by a vibrating structure supported by a support, including a transducer interposed between the vibrating structure and the support to transform mechanical energy of vibrations into electrical energy. The transducer includes a flextensional structure having a first axis perpendicular to a second axis, a stack of piezoelectric elements adapted to produce electrical energy when stressed, the stack stressed in compression by the flextensional structure along the first axis so that deformation of the structure modifies the compressive stress applied to the stack, two peripheral fasteners are secured to the flextensional structure, each fastener disposed along the second axis, a first fastener for securing the flextensional structure to the vibrating structure, a second fastener for securing the flextensional structure to the support, at least one fastener integrates an elastic suspension, a shunt connected to the piezoelectric stack to dissipate electrical energy.