Investigation of an electrostatically actuated imperfect circular microplate under transverse pressure for pressure sensor applications

In this paper, we present static and dynamic analysis of an electrostatically actuated imperfect circular microplate under transverse pressure. In modelling of the microplate, we have included both von Kármán geometric and electrostatic force nonlinearities in the development of the equation of motion. The equation of motion has been solved using Galerkin based reduced order modelling technique. The developed reduced order model has been first validated by comparing it with finite element simulation results. Further, the effects of imperfection as initial curvature and uniform transverse pressure have been investigated on the static and dynamic characteristics of the electrostatically actuated circular microplate. We have also investigated the effects of imperfection and applied DC voltage on the pressure sensitivity of the circular microplate. We have found that both imperfection and electrostatic load are responsible for appreciable variations in sensitivity. This detailed investigation is useful to design an imperfect micro pressure sensor.

Frequency characteristics of a viscoelastic graphene nanoplatelet–reinforced composite circular microplate

This is the first research on the frequency analysis of a graphene nanoplatelet composite circular microplate in the framework of a numerical-based generalized differential quadrature method. Stresses and strains are obtained using the higher order shear deformation theory. The microstructure is surrounded by a viscoelastic foundation. Rule of the mixture is used to obtain varying mass density and Poisson’s ratio, whereas the module of elasticity is computed by a modified Halpin–Tsai model. Governing equations and boundary conditions of the graphene nanoplatelet composite circular microplate are obtained by implementing Hamilton’s principle. The results show that outer to inner radius ratio [Formula: see text], ratios of length scale and nonlocal to thickness ( l/ h and [Formula: see text]), and graphene nanoplatelet weight fraction [Formula: see text] have significant influence on the frequency characteristics of the graphene nanoplatelet composite circular microplate. Another necessary consequence is that by increasing the value of [Formula: see text], the distribution of the displacement field extends from radial to tangent direction, especially in the lower mode numbers; this phenomenon appears much more remarkable. A useful suggestion of this research is that for designing the graphene nanoplatelet composite circular microplate at a low value of [Formula: see text], [Formula: see text] and [Formula: see text] should be given more attention, simultaneously. An interesting result which has come down from the article is that the effect of [Formula: see text] on the dimensionless frequency of the structure is really dependent on the value of C d.

Nonlinear Static and Dynamic Behavior of an Imperfect Circular Microplate Under Electrostatic Actuation

In this article, we investigate the nonlinear static and dynamic behavior of a clamped circular microplate in presence of imperfections. By taking in account the von Kàrmàn nonlinearity, the geometrical imperfections lead to a significant delay in static pull-in occurrence. Numerical simulations are performed in the frequency domain to study the dynamic behavior under primary resonance. A parametric analysis is conducted with respect to actuation voltages and initial deflection in order to capture the competition between hardening and softening behavior. Interestingly, we show that a geometric imperfection can change the type of nonlinear response from softening to hardening. In practice, the imperfection can be functionalized to enhance the performances of capacitive micromachined ultrasonic transducers.

Analysis of Thermoelastic Damping in Bilayered Circular Microplate Resonators

Predicting thermoelastic damping is essential in the design of the next generation of layered composite microresonators. We present an analytical model for thermoelastic damping in circular microplates using the framework developed by Bishop and Kinra. The thermoelastic damping spectrum will exhibit two distinct peaks when the thermal conductivity of the substrate is much greater or less than that of the film. Increment of the thickness of a layer with the bigger Zener’s modulus will increase the peak damping.

Thermoelastic Damping in Laminated Composite Circular Microplate Resonators

High quality factor is an essential requirement in the design of microsensors used for sensing and communications applications. In previous works, some analytical models have been developed for thermoelastic damping in monolayer structure and multi-layered beam. This paper proposes a new model for thermoelastic damping in symmetric, three-layered, laminated, microplate resonators. Our approach utilizes the analytical framework developed by Bishop and Kinra and Gaussian curvature. The effect of volume fraction is numerically calculated. It is noticed that the maximum damping is determined by volume fraction, which is independent of the single layer thickness. The thinner plate is, the higher frequency is that reach the maximum damping.