Bimorph Disk Actuator Composite Ring Design
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Solution Overview
Problem
Current piezoelectric actuators for synthetic jets, such as unimorph and bimorph topologies, face inefficiencies due to significant strain energy being used to bend metallic substrates or passive outer rings, reducing the energy available for air puff generation, limiting the performance of synthetic jets in active flow control applications.
Innovation Solution
A bimorph disk actuator design featuring standard piezoceramic disks with customizable composite rings around the substrate, allowing for adjustable stiffness to optimize performance indicators like displacement, force, and resonant frequency, by varying the composite ring thickness and material properties, thereby matching the requirements of synthetic jets without needing custom piezoceramic disks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metallic substrate is used in unimorph topology to provide structural support, then the actuator has sufficient mechanical strength, but a significant amount of piezoelectric induced strain energy is consumed to bend the stiff metallic substrate, reducing the energy available for air puff generation
Solution Approach 1:
The patent removes the metallic substrate from the actuator structure, extracting the harmful element that consumed excessive strain energy. The bimorph actuator uses only piezoceramic wafers bonded together with a thin layer of epoxy and Kapton, eliminating the stiff metallic substrate that caused energy loss while maintaining sufficient structural integrity through the ceramic-epoxy-ceramic construction.
Solution Approach 2:
The patent employs composite materials by bonding two piezoceramic wafers together with a thin layer of epoxy and Kapton encapsulation. This composite structure provides the necessary mechanical strength without the excessive stiffness of metallic substrates, allowing efficient energy transfer to generate air puffs while maintaining structural integrity.
2Stability of the object's composition
If a passive outer ring is added to the bimorph actuator to provide structural support, then the actuator maintains its shape, but the outer ring consumes additional strain energy and reduces the overall performance of the synthetic jet
Solution Approach 1:
The patent removes the passive outer ring from the bimorph actuator structure, extracting the element that was consuming additional strain energy. The actuator achieves sufficient structural stability through the bonded piezoceramic wafers and thin encapsulation layer without requiring an energy-consuming outer ring, thereby improving overall synthetic jet performance.
3Reliability
If custom piezoceramic disks are manufactured to optimize actuator performance, then the performance indicators (displacement, force, resonant frequency) can be precisely matched, but the manufacturing cost and complexity increase significantly
Solution Approach 1:
The patent achieves performance optimization by changing geometric parameters (wafer dimensions, bonding layer thickness, encapsulation thickness) rather than manufacturing custom piezoceramic disks. This allows precise matching of performance indicators like displacement, force, and resonant frequency using standard off-the-shelf piezoceramic wafers, significantly reducing manufacturing cost and complexity.
Solution Approach 2:
The patent segments the actuator into distinct functional components: standard piezoceramic wafers for actuation, thin epoxy layer for bonding, and Kapton encapsulation for protection. This segmentation allows each component to be optimized independently, with standard wafers providing reliable performance and the bonding/encapsulation layers fine-tuning the overall actuator characteristics without requiring custom ceramic manufacturing.
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 design enhances the efficiency of synthetic jets by directing strain energy towards air flow generation, improving airflow at the same voltage, and reducing manufacturing costs by using standard piezoceramic disks and inexpensive composite materials, thus improving aerodynamic efficiency and reducing operational costs.
Implementation Method 1
Due to the converse piezoelectric effect, the applied electric field causes stresses and mechanical deformation through the thickness of the plate
Implementation Method 2
corresponding stresses and mechanical deformation occur in the plane of the plate due to the Poisson effect
Data Source
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Figure 5~6
AI summary
A bimorph disk actuator is disclosed including a substrate formed from a substrate composite material and having a first substrate surface and a second substrate surface, a first piezoceramic disk rigidly connected to the first substrate surface of the substrate, a second piezoceramic disk rigidly connected to the second substrate surface of the substrate, and a first composite ring formed from a first ring composite material, rigidly connected to the first substrate surface and surrounding the first piezoceramic disk. A second composite may be rigidly connected to the second substrate surface and surrounding the second piezoceramic disk. A method and apparatus for forming the bimorph disk actuator are also disclosed.