Marek Borowiec

Performance of a piezoelectric energy harvester driven by air flow

A turbulent wind source for possible energy harvesting is considered. To increase the amplitude of vibration, we apply a magnetopiezoelastic oscillator having a double well Duffing potential. The output voltage response of the system for different level of wind excitations is analyzed. The energy harvesting appeared to be the most efficient for the conditions close to the stochastic resonance region where the potential barrier was overcame.

Energy harvesting by two magnetopiezoelastic oscillators with mistuning

We examine an energy harvesting system of two magnetopiezoelastic oscillators coupled by electric circuit and driven by harmonic excitation. We focus on the effects of synchronization and escape from a single potential well. In the system with relative mistuning in the stiffness of the harvesting oscillators, we show the dependence of the voltage output for different excitation frequencies.

ENERGY HARVESTING IN PIEZOELASTIC SYSTEMS DRIVEN BY RANDOM EXCITATIONS

The inverted elastic beam is proposed as an energy harvester. The beam has a tip mass and piezoelectric layers which transduce the bending strains induced by the stochastic horizontal displacement into electrical charge. The efficiency of this nonlinear device is analyzed, focusing on the region of stochastic resonance where the beam motion has a large amplitude. Increasing the noise level allows the motion of the beam system to escape from single well oscillations and thus generate more power.

Phase locking and rotational motion of a parametric pendulum in noisy and chaotic conditions

The effect of noise on the rotational mode of a pendulum which is excited kinematically in vertical direction has been analysed. We have shown that for weak noise, transitions from the oscillations to rotations and vice versa are possible. For stronger noise, the rotational solution as an independent synchronized mode vanishes. When searching for the rotational motion we observed an intermittent transition to chaos induced by noise.

Nonlinear Response of an Oscillator with a Magneto-Rheological Damper Subjected to External Forcing

This paper examines the dynamics of a single degree of freedom nonlinear model, representing a quarter of an automobile with a semi-active, nonlinear suspension. Assuming that the kinematic excitation caused by the road surface profile is harmonic, the principal resonance and frequency entrainment are obtained for regions of the model parameters. Changing the excitation frequency and road profile amplitude we analyze possible chaotic vibrations and bifurcations of the system.

Noise Effected Energy Harvesting in a Beam with Stopper

An autonomous system of energy supplier to low power devices or wireless sensors is one of the most important motivations for energy harvesting based on ambient mechanical vibrations. In traditional approach, harvesters were based on a linear mechanical resonator combined with an electro-mechanical transducer working in the resonance region, i.e. in a relatively small range of frequencies. Here, we study a frequency broadband nonlinear resonator with impact characteristics with the aim of increasing the range of operativity of the system. The excitations are modeled by kinematic forcing possessing periodic and stochastic components, motivated by realistic ambient conditions. We show how the noise component of the excitation influences the stability of the solution.

Energy Harvesting in a Nonlinear Cantilever Piezoelastic Beam System Excited by Random Vertical Vibrations

The vertical elastic beam with vertical ambient excitation is proposed as an energy harvester. The beam has a tip mass and piezoelectric patches which transduce the bending strains induced by the stochastic force caused by vertical kinematic forcing into electrical charge. We focus on the region with a fairly large amplitude of voltage output where the beam overcomes the potential barrier. Increasing the noise level allows the transition from single well oscillations to inter-well stochastic jumps with more power generation.

Dynamic Response of a Pendulum-Driven Energy Harvester in the Presence of Noise

This paper presents time- and frequency-domain analyses of a previously reported wave energy harvesting system in the presence of noise. The energy harvester comprises a pendulum that drives two DC generators connected electrically in series. A mechanical model of the wave energy harvester is developed and simulated in Matlab. The output voltage and output power of the energy harvester is evaluated and compared for two input signal types: a deterministic case and a stochastic case. The latter consists of a white noise random excitation source that is bounded in amplitude at a fixed standard deviation. Simulation results indicate that a stochastic input signal shows considerable influence on the output characteristics of the energy harvester. The simulation models developed in this paper can be used to complement the design of resonant frequency tuning electronics for energy harvesting systems.

Vertical beam modal response in a broadband energy harvester

We examined energy harvesting using a vertical composite laminate beam with an additional moving mass subjected to kinematic harmonic excitation. The gravity effect and the moving tip mass applied to the system cause considerable changes in effective spring-mass characteristics of the bending beam. Simultaneously, we observed dynamical beam damping by an additional degree of freedom and non-linear effects including friction between the moving mass and the beam structure. The experiments were performed on the beam excited kinematically by a shaker, while beam velocity measurements were made by a scanning laser vibrometer. We applied modal analysis in the limit of a fairly low excitation level. The selected modal vibrations are illustrated by corresponding output time series.

Multiple Solutions and Corresponding Power Output of Nonlinear Piezoelectric Energy Harvester

Energy harvesting is used for an increasing number of small electronic devices and sensors in various applications. Ambient sources of vibration are exploited to provide low levels of power to devices where battery replacement is difficult. One of the simplest concepts for energy harvesting from mechanical vibrations is based on a linear mechanical resonator combined with a piezoelectric transducer. In this case, mechanical energy scavenged from mechanical stress or strain is transferred to electrical voltage. However, such devices work most efficiently in the vicinity of a resonant frequency and it is difficult to tune them in the presence of variable ambient conditions. On the other hand, nonlinear devices seem to be more effective in such conditions due to the broader frequency spectrum of their response. In this paper, we analyse the dynamics of a nonlinear flexible beam with a piezoelectric layer and a magnetic tip mass under the harmonic excitation. The additional magnets define system multistability, including a tristable configuration. The resonant curves and basins of attraction are predicted and can be helpful in choosing the optimal values of the system parameters.