A highly efficient simulation technique for piezoelectric energy harvesters

This paper presents a new numerical technique which is aimed at obtaining fast and accurate simulations of piezoelectric beams, used in inertial energy harvesting MEMS. The execution of numerical analyses is greatly important in order to predict the actual behaviour of MEMS device and to carry out the optimization process on the basis of Design of Experiments (DOE) techniques. In this paper, a refined, yet simple, model is proposed with reference to the multi-physics problem of piezoelectric energy harvesting by means of laminate cantilevers. The proposed model is calibrated and validated with reference to 3D finite element analyses

On the application of piezolaminated composites to diaphragm micropumps

This paper deals with the numerical simulation of piezolaminated microplates adopted as actuators in micropumps. The performances of piezoelectric actuation is critically assessed by means of comparisons with devices based on the electrostatic force

Experimental verification of a bridge-shaped, nonlinear vibration energy harvester

This paper reports a comprehensive modeling and experimental characterization of a bridge shaped nonlinear energy harvester. A doubly clamped beam at large deflection requires stretching strain in addition to the bending strain to be geometrically compatible, which stiffens the beam as the beam deflects and transforms the dynamics to a nonlinear regime. The Duffing mode non-linear resonance widens the frequency bandwidth significantly at higher frequencies than the linear resonant frequency. The modeling includes a nonlinear measure of strain coupled with piezoelectric constitutive equations which end up in nonlinear coupling terms in the equations of motion. The main result supports that the power generation is bounded by the mechanical damping for both linear and nonlinear harvesters. Modeling also shows the power generation is over a wider bandwidth in the nonlinear case. A prototype is manufactured and tested to measure the power generation at different load resistances and acceleration amplitudes. The prototype shows a nonlinear behavior with well-matched experimental data to the modeling

On the application of piezolaminated composites to diaphragm muicropumps

This paper deals with the numerical simulation of piezolaminated microplates adopted as actuators in micropumps. The performances of piezoelectric actuation are critically assessed by means of comparisons with devices based on the electrostatic force. In order to perform accurate simulations of the micropump behavior, the theory of laminates is adopted, account taken of the piezoelectric coupling. Both static and dynamic analyses have been performed, in order to obtain information on the optimal configuration for the micropump

Numerical simulations of piezoelectric effects

This paper is focused on the numerical simulation of piezoelectric effects, in view of their application in MEMS harvesters and actuators. In order to obtain a fast and accurate prediction of dynamic behavior, a simple 1-DOF model has been introduced for thin piezoelectric beams. The validation of the model has been carried out by comparison with full 3D simulations via commercial codes

Experimental verification of a bridge-shaped, non-linear vibration energy harvester

This paper reports the modeling and a first experimental characterization of a bridge-shaped doubly clamped nonlinear energy harvester. The doubly clamped beam at large deflection induces stretching strain in the layers in addition to the bending strain, which stiffens the beam as the beam deflects and transforms the dynamics to the nonlinear regime widening the frequency bandwidth. The sectional behavior of the bridge-beam has been studied through the Classical Lamination Theory (CLT) specifically modified to introduce the piezoelectric coupling and nonlinear Green-Lagrange strain tensor. A lumped parameter model has been built through separation of variables method, this results in coupled motion equations which include additional non-common terms originating from a correct analysis of piezoelectrics coupling in nonlinear strain context. The model has been validated through tests on a mesoscale prototype. The prototype consists of a Macro Fiber Composite (MFC, Smart-material) piezoelectric patch glued on a thin aluminum layer and a lead proof mass is attached at mid span. The beam is doubly clamped on an aluminum support. The device is tested in open circuit and the frequency response is measured at different acceleration amplitudes. Despite of the fact that the resulting high mechanical damping reduces the oscillation amplitude, the experimental data show a significant nonlinear behavior. These results are compared to the modeling showing good accordance

Modelling of a bridge-shaped nonlinear piezoelectric energy harvester.

Piezoelectric MicroElectroMechanical systems (MEMS) energy harvesting is an attractive technology for harvesting small magnitudes of energy from ambient vibrations. Increasing the operating frequency bandwidth of such devices is one of the major issues for real world applications. A MEMS-scale doubly clamped nonlinear beam resonator is designed and developed to demonstrate very wide bandwidth and high power density. In this paper a first complete theoretical discussion of nonlinear resonating piezoelectric energy harvesting is provided. The sectional behaviour of the beam is studied through the Classical Lamination Theory (CLT) specifically modified to introduce the piezoelectric coupling and nonlinear Green-Lagrange strain tensor. A lumped parameters model is built through Rayleigh-Ritz Method and the resulting nonlinear coupled equations are solved in the frequency domain through the Harmonic Balance Method (HBM). Finally, the influence of external load resistance on the dynamic behaviour is studied. The theoretical model shows that the power generation of nonlinear resonant harvesters is spread out on a wider bandwidth but it is theoretically bounded by the mechanical damping of the dynamic system as for linear resonating harvesters

Modeling of a bridge-shaped nonlinear piezoelectric energy harvester

Piezoelectric microelectromechanical systems (MEMS) energy harvesting is an attractive technology for harvesting small energy from ambient vibrations. Increasing the operating frequency bandwidth of such devices is one of the major challenges to be solved for real-world applications. A MEMS-scale doubly clamped nonlinear beam resonator has demonstrated very wide bandwidth and high-power density among the energy harvesters reported. In this paper, a first complete theoretical discussion of nonlinear resonance-based piezoelectric energy harvesting is provided. The sectional behavior of the beam has been studied through the Classical Lamination Theory (CLT) specifically modified to introduce the piezoelectric coupling and nonlinear Green-Lagrange strain tensor. A lumped parameter model has been built through Rayleigh???Ritz method and the resulting nonlinear coupled equations have been solved in the frequency domain through the Harmonic Balance Method (HBM). Finally, the influence of external load resistance on the dynamic behavior has been studied. The theoretical model shows that nonlinear resonant harvesters have much wider power bandwidth than that of linear resonators but their maximum power is still bounded by the mechanical damping as is the case for linear resonating harvester

Numerical simulations of piezoelectric MEMS energy harvesters

The application of piezoelectric materials in MEMS energy harvesters is continuously increasing, with the immediate corollary of a fundamental need for improved computational tools in order to optimize the performances at the design level. In this paper, a refined, yet simple model is proposed with the aim of providing fast and insightful solutions to the multi-physics problem of piezoelectric energy harvesting. The main objective is to retain a simple structural model (Euler-Bernoulli beam), with the inclusion of effects connected to the actual threedimensional shape of the device. A thorough presentation of the analytical model is presented, along with its validation by comparison with the results of full 3D computations

Modelling of a bridge-shaped nonlinear piezoelectric energy harvester

Piezoelectric MicroElectroMechanical Systems (MEMS) energy harvesting is an attractive technology for harvesting small magnitudes of energy from ambient vibrations. Increasing the operating frequency bandwidth of such devices is one of the major issues for real world applications. A MEMS-scale doubly clamped nonlinear beam resonator is designed and developed to demonstrate very wide bandwidth and high power density. In this paper a first complete theoretical discussion of nonlinear resonating piezoelectric energy harvesting is provided. The sectional behaviour of the beam is studied through the Classical Lamination Theory (CLT) specifically modified to introduce the piezoelectric coupling and nonlinear Green-Lagrange strain tensor. A lumped parameter model is built through Rayleigh-Ritz Method and the resulting nonlinear coupled equations are solved in the frequency domain through the Harmonic Balance Method (HBM). Finally, the influence of external load resistance on the dynamic behaviour is studied. The theoretical model shows that nonlinear resonant harvesters have much wider power bandwidth than that of linear resonators but their maximum power is still bounded by the mechanical damping as is the case for linear resonating harvesters