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Non-Linear Piezoelectric Actuator with a Preloaded Cantilever Beam
摘要： Piezoelectric actuation is widely used for the active vibration control of smart structural systems, and corresponding research has largely focused on linear electromechanical devices. This paper investigates the design and analysis of a novel piezoelectric actuator that uses a piezoelectric cantilever beam with a loading spring to produce displacement outputs. This device has a special nonlinear property relating to converting between kinetic energy and potential energy, and it can be used to increase the output displacement at a lower voltage. The system is analytically modeled with Lagrangian functional and Euler–Lagrange equations, numerically simulated with MATLAB, and experimentally realized to demonstrate its enhanced capabilities. The model is validated using an experimental device with several pretensions of the loading spring, therein representing three interesting cases: a linear system, a low natural frequency system with a pre-buckled beam, and a system with a buckled beam. The motivating hypothesis for the current work is that nonlinear phenomena could be exploited to improve the effectiveness of the piezoelectric actuator’s displacement output. The most practical configuration seems to be the pre-buckled case, in which the proposed system has a low natural frequency, a high tip displacement, and a stable balanced position.
关键词： piezoelectric,cantilever,Hamilton’s principle,actuator,pretension,transducer
更新于2025-09-19 17:15:36
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Frequency characteristics of a GPL-reinforced composite microdisk coupled with a piezoelectric layer
摘要： This is the ?rst research on the frequency analysis of a graphene nanoplatelet composite (GPLRC) microdisk in the framework of a numerical-based generalized differential quadrature method. The stresses and strains are obtained using the higher-order shear deformable theory. Rule of mixture is employed to obtain varying mass density, thermal expansion, and Poisson’s ratio, while module of elasticity is computed by modi?ed Halpin–Tsai model. Governing equations and boundary conditions of the GPLRC microdisk covered with piezoelectric layer are obtained by implementing Hamilton’s principle. Regarding perfect bonding between the piezoelectric layer and core, the compatibility conditions are derived. In addition, due to the existence of piezoelectric layer, Maxwell’s equation is derived. The results show that outer-to-inner ratio of radius (Ro/Ri), ratios of length scale and nonlocal to thickness (l/h and μ/h), ratio of piezoelectric to core thickness (hp/h), applied voltage, and GPL weight fraction (gGPL) have signi?cant in?uence on the frequency characteristics of the GPLRC microdisk. Another important consequence is that in addition to the nonlinear indirect effects of applied voltage on the natural frequency of the GPLRC microdisk covered with piezoelectric for each speci?c value of Ro/Ri, the impact of the Ro/Ri on the natural frequency is indirect. A useful suggestion of this research is that, for designing the GPLRC circular microplate at the low value of the Ro/Ri should be more attention to the gGPL and Ro/Ri, simultaneously.
关键词： Higher-order shear deformable theory,Halpin–Tsai model,Microdisk,Piezoelectric layer,Hamilton’s principle,Maxwell’s equation,Generalized differential quadrature method,Frequency analysis,Graphene nanoplatelet composite (GPLRC)
更新于2025-09-19 17:13:59
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Piezoelectric Disc Transformer Modeling Utilizing Extended Hamilton's Principle
摘要： Piezoelectric transformers (PTs) are resonant electromechanical voltage conversion devices used in a variety of applications including voltage boosting and galvanic isolation. They offer advantages over electromagnetic voltage transformers (EMTs), including high energy density as well as the potential for monolithic fabrication, making them well suited to small-scale microelectromechanical (MEMS) applications. Among various PT topologies, circular discs lend themselves to microfabrication, and are considered here. In order to gain fundamental understanding of disc PT dynamics, this work applies the Extended Hamilton’s Principle of variational calculus to the piezoelectric electric enthalpy, using cylindrical coordinates, in order to derive electromechanical constitutive equations for bulk disc transformers. The use of the Hamilton approach in this work supports the integration of mechanical tethers that physically support the disc, allowing the model to be applied to device designs that are compatible with monolithic microfabrication from sheets of bulk piezoelectric material. Using the integrated model, voltage gain (output voltage / input voltage) is predicted as a function of multiple variables including electrode area ratio, device size, load impedance, and is compared against finite element numerical and experimental prototype results for verification. Prototype 4mm diameter tethered disc PTs on the order of .002cm3, two orders smaller than the bulk PT literature, were fabricated to validate the proposed model, and had peak voltage gains over 2.
关键词： Extended Hamilton’s Principle,Piezoelectric transformers,voltage conversion,MEMS,microfabrication
更新于2025-09-10 09:29:36