Planar Piezoelectric Actuator with Inclined Fibers for Shear Movement
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Solution Overview
Problem
Existing piezoelectric actuators with a rectangular flat design have a limited amplitude of angular distortion, restricting their effectiveness in applications requiring significant shear movement, such as in aeronautics for adapting aerodynamic elements.
Innovation Solution
A piezoelectric actuator with a sandwich structure featuring piezoelectric fibers inclined at an angle between 2° and 40°, filled with an incompressible elastic material, and integrated with non-deformable elements and a rigid glue system to enhance angular distortion and force transmission, allowing for greater shear movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the angle of inclination of piezoelectric fibers is increased to 45° to transmit shear movement, then the rigidity and force transmission are improved, but the angular distortion amplitude is limited to approximately 1200 μdef
Solution Approach 1:
The patent changes the inclination angle parameter of piezoelectric fibers from the conventional 45° to a range of 0° to 30°, which fundamentally alters the deformation mechanism. This parameter change enables the actuator to achieve angular distortions greater than twice those of traditional 45° designs while maintaining force transmission capability through the optimized angle range
Solution Approach 2:
The patent employs a composite structure combining piezoelectric fibers with an incompressible elastic material matrix and non-deformable elements. This composite approach allows the flexible fiber assembly to achieve large angular distortions while the rigid non-deformable elements ensure effective force transmission to the electrode layers, resolving the contradiction between amplitude and strength
2Strength
If rigid layers with high shear strength are used to transmit shear movement, then the force transmission is improved, but mechanical losses increase due to shear strength in the glue layers
Solution Approach 1:
The patent changes the mechanical properties parameter of the matrix material from rigid (high shear strength) to incompressible elastic (low shear modulus). This parameter change reduces mechanical losses by minimizing shear resistance in the matrix while maintaining effective force transmission through the optimized fiber inclination and non-deformable element structure
Solution Approach 2:
The patent substitutes the traditional rigid glue layer shear transmission mechanism with a new mechanism based on piezoelectric fiber elongation and direct bonding to non-deformable elements. This substitution eliminates the need for shear strength in intermediate glue layers, thereby reducing mechanical losses while maintaining force transmission capability
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 achieves angular distortions greater than twice that of traditional designs, with improved force transmission and reduced mechanical losses, enabling more significant deformation and efficient force application in the shear direction.
Implementation Method 1
at least one active layer comprising piezoelectric fibers parallel to one another and inclined with respect to the direction, the active layer being placed between at least two layers carrying electrodes disposed so as to be able to cause on command a variation in length of the fibers
Implementation Method 2
the spaces between piezoelectric fibers in the active layer are filled with an incompressible elastic material with a dielectric strength greater than that of the fibers
Implementation Method 3
the ends of each of the fibers are adhesively bonded to the non-deformable elements by means of a rigid glue
Data Source
AI summary
An actuator providing a large shear movement in a chosen direction. The angle of inclination of the fibers relative to the chosen direction is larger than 2° and smaller than 40°; the spaces between the piezoelectric fibers of the active layer are filled with an incompressible elastic material; the active layer comprises at least two dimensionally stable elongate elements parallel to the chosen direction; the ends of each fiber are adhesively bonded to said dimensionally stable elements using a rigid adhesive; and said dimensionally stable elements are adhesively bonded, by a rigid adhesive, to said electrode-bearing layers.