Comparative numerical studies of electromechanical finite element vibration power harvester approaches of a piezoelectric unimorph

Abstract

Emerging micro-power harvester research using smart material components shows viable self-powered devices capable of capturing mechanical motion and converting it into useful electrical energy that can be further used to supply electrical voltage into rechargeable power storage via a power management electronic circuit. The micro-power harvesters using piezoelectric materials cover a wide range of applications for powering thin film battery technology and wireless sensor systems that can be used to monitor the health condition of machines and infrastructure and biomedical implant devices. This research focuses on the development of a novel numerical direct method technique with non-orthonormality based on the electromechanical vector transformation for modelling the selfpowered cantilevered piezoelectric unimorph beam under input base excitation. The proposed finite element piezoelectric unimorph beam equations were formulated using Hamiltonian's principle for formulating the global matrices of electromechanical dynamic equations based on the electromechanical vector transformation that can be further employed to derive the electromechanical frequency response functions. This numerical technique was modelled using electromechanical discretisation consisting of mechanical and electrical discretised elements due to the electrode layers covering the surfaces of the piezoelectric structure, giving the single voltage output. The reduced equations are based on the Euler-Bernoulli beam assumption for designing the typical power harvesting device. The proposed finite element models were also compared with orthonormalised electromechanical finite element response techniques, giving accurate results in the frequency domains.

Mechanical frequency up-conversion for sub-resonance, low-frequency vibration harvesting

“…Harvesting ambient vibration energy is an increasingly attractive research area due to the ubiquity of this energy source in everyday life (Beeby et al, 2006; Warman et al, 2013). Of particular interest is harvesting vibration energy from human motion (Saha et al, 2008) for powering portable and remote systems (Pancharoen et al, 2014)…”

Modelling and Optimization of Orientated Beam with Tip Mass for Vibration Energy Harvesting using Piezoelectric Patches

“…The importance to find the natural frequency is to obtain maximum output. The validation of the model is given in Tables 2 and 3 The MatLab programme is validated with material and geometrical properties of literature paper [3] and [5] and comparison of natural frequencies of unimorph piezoelectric energy harvester beam without tip mass and with tip mass at [4] is shown in Fig. 3.…”

“…Research of piezoelectric elements in energy conversion applications necessitates a thorough understanding of solid mechanics and geometrical shapes [2]. Researchers have focused on analytical and numerical studies of unimorph and bimorph beam which forms the basis for the study of energy harvesting [3][4][5] due to its compatibility and ease of applications. Authors have studied experimentally, the effect of orientation of beam by attaching harvester to human leg and concluded that optimum results are obtained for 70 o orientation of harvester with reference to coordinate system [6].…”