We propose and experimentally validate a first-principles based model for the nonlinear piezoelectric response of an electroelastic energy harvester The analysis herein highlights the importance of modeling inherent piezoelectric nonlinearities that are not limited to higher order elastic effects but also include nonlinear coupling to a power harvesting circuit Furthermore, a nonlinear damping mechanism is shown to accurately restrict the amplitude and bandwidth of the frequency response The linear piezoelectric modeling framework widely accepted for theoretical investigations is demonstrated to be a weak presumption for near-resonant excitation amplitudes as low as 05 g in a prefabricated bimorph whose oscillation amplitudes remain geometrically linear for the full range of experimental tests performed (never exceeding 025% of the cantilever overhang length) Nonlinear coefficients are identified via a nonlinear least-squares optimization algorithm that utilizes an approximate analytic solution obta

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Nonlinear piezoelectricity in electroelastic energy harvesters: Modeling and experimental identification

Electro-mechanical vibration analysis of functionally graded piezoelectric porous plates in the translation state

This paper investigates the static bending, free vibration, and dynamic response of monomorph, bimorph, and multimorph actuators made of functionally graded piezoelectric materials (FGPMs) under a combined thermal-electro-mechanical load by using the Timoshenko beam theory. It is assumed that all of the material properties of the actuator, except for Poisson's ratio, are position dependent due to a continuous variation in material composition through the thickness direction. Theoretical formulations are derived by employing Hamilton's principle and include the effect of transverse shear deformation and axial and rotary inertias. The governing differential equations are then solved using the differential quadrature method to determine the important performance indices, such as deflection, reaction force, natural frequencies, and dynamic response of various FGPM actuators. A comprehensive parametric study is conducted to show the influence of shear deformation, temperature rise, material composition, slenderness ratio, end support, and total number of layers on the thermo-electro-mechanical characteristics. It is found that FGPM monomorph actuators exhibit the so-called 'non-intermediate' behavior under an applied electric field.

https://iopscience.iop.org/article/10.1088/0964-1726/16/3/028/pdf

Thermo-electro-mechanical characteristics of functionally graded piezoelectric actuators

Now a days, sandwich beams and plates made of functionally graded (FG) materials are widely used in many engineering industries. Therefore, several modeling techniques and solution methods ...

Modeling and analysis of functionally graded sandwich beams: a review

Nonlinear piezoelectric effects in flexural energy harvesters have recently been demonstrated for drive amplitudes well within the scope of anticipated vibration environments for power generation. In addition to strong softening effects, steady-state oscillations are highly damped as well. Nonlinear fluid damping was previously employed to successfully model drive dependent decreases in frequency response due to the high-velocity oscillations, but this article instead harmonizes with a body of literature concerning weakly excited piezoelectric actuators by modeling nonlinear damping with nonconservative piezoelectric constitutive relations. Thus, material damping is presumed dominant over losses due to fluid-structure interactions. Cantilevers consisted of lead zirconate titanate (PZT)-5A and PZT-5H are studied, and the addition of successively larger proof masses is shown to precipitate nonlinear resonances at much lower base excitation thresholds while increasing the influence of higher-order nonlineari...

Nonlinear nonconservative behavior and modeling of piezoelectric energy harvesters including proof mass effects

Vibration analysis of the internal combustion (IC) engine components is extremely helpful in optimizing the design of these components and has direct bearing on the engine life. This paper presents an experimental and numerical modal analysis of IC engine camshaft. The experimental modal analysis of camshaft excited using impact hammer is performed with the help of a laser vibrometer. The signals from the experiments are obtained in the time domain and are later converted into the frequency domain using fast Fourier transformation (FFT) with the help of MATLAB program. The numerical modal analysis is performed using finite element modeling (FEM) software ANSYS Workbench 14.5. The purpose of this experiment is to validate the finite element model of camshaft using the experimental data, so that the same FEM model of camshaft can be used with confidence for more complex boundary conditions or real operating conditions. To achieve this aim, the natural frequencies and mode shapes of camshaft obtained through experiment and FEM are compared. The methodology presented and the results are useful in optimizing the design of camshaft to be used in IC engine.

Experimental Investigation Using Laser Vibrometer and Finite Element Modeling for Modal Analysis of Camshaft

Piezoelectric vibrating shell is the major component of the various equipments related to mechanical, nuclear, aeronautical and aerospace engineering. Shells especially exhibit certain effects that are not present in beams or even in plates. Analysis of vibrational characteristics of functionally graded piezoelectric circular cylindrical shell is quit complex than beams and plates. This is because the coupling of vibration of shell between the three directions can no longer be neglected. Dynamic analysis of FGPM continuum is quite complex, due to the synchronization of electric and mechanical terms. Closed form solution for complex FGPM model by analytical method is quite a tedious task. Approximation method provides an alternate path for solving such kind of problems. Paper contains free vibration analysis of a full three dimensional FGPM cylindrical shell model excited under d15 effect. Shear piezoelectric coupling coefficient d15 is much higher than the other piezoelectric coefficients d31 or d33. Rayleigh–Ritz, an approximation method, is used to obtain the eigenvectors and eigenfrequencies for FGPM cylindrical shell. Orthogonal polynomial functions are used with Rayleigh–Ritz method to formulate the linear eigenvalue problem. Higher order polynomials are generated by Gram–Schmidt method. MATLAB 2015a Symbolic Toolbox is used for calculation and obtained solution is validated using commercial finite element software COMSOL Multiphysics 2014.

Sandeep Kumar Parashar

Papers

Experimental Investigation Using Laser Vibrometer and Finite Element Modeling for Modal Analysis of Camshaft

On Free Vibration Analysis of FGPM Cylindrical Shell Excited Under d 15 Effect