Piezoelectric Actuator Non-Uniform Density Stress Alignment
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Solution Overview
Problem
Piezoelectric actuated structural systems face inefficiencies in promoting desired structural Eigenmodes of vibration while minimizing undesired modes, due to uniform actuation distribution, which affects the coupling of actuation forces to displacement fields.
Innovation Solution
The solution involves patterning piezoelectric material with non-uniform area densities and electrical connections to match the stress gradient distribution, ensuring efficient actuation of desired Eigenmodes by coupling actuation forces to areas of greatest stress and curvature, and using flexible members like flexures to allow angular displacement of scanning platforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform piezoelectric material distribution is used, then manufacturing is simplified, but actuation efficiency is reduced due to poor coupling with stress gradients
Solution Approach 1:
The patent applies local quality by varying the area density of piezoelectric material across different regions of the substrate. Specifically, the piezoelectric material is patterned with higher area density in regions of high stress concentration and lower area density in regions of low stress, creating a non-uniform distribution that optimizes the coupling between actuation forces and the displacement field for desired Eigenmodes.
2Productivity
If piezoelectric material area density is increased in high stress regions, then actuation efficiency is improved, but material usage and device complexity increase
Solution Approach 1:
The patent employs parameter changes by systematically varying the area density parameter of the piezoelectric material across the substrate surface. This controlled variation in material distribution parameter allows optimization of actuation efficiency for specific Eigenmodes while managing the overall device complexity through a structured rather than arbitrary pattern.
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 enhances actuation efficiency by aligning piezoelectric material distribution with stress gradients, promoting targeted structural Eigenmodes of vibration while minimizing unwanted modes, thereby optimizing energy transfer and displacement in piezoelectric actuated devices.
Implementation Method 1
An electric field within the piezoelectric film produces a mechanical stress
Data Source
AI summary
A piezoelectric actuated device includes one or more areas of piezoelectric material coupled to a substrate. The piezoelectric material may be placed on regions of the substrate that exhibit the greatest curvature and stress when the device is vibrating according to a desired structural Eigenmode of vibration. The piezoelectric material may have a non-uniform density.