Modeling, Simulation and Performance Analysis of Multichannel Mems Piezoelectric Cantilevers for Cochlear Implantable Module

This work presents the enhanced area-efficient Multi-channel MEMS (Micro-Electrical Mechanical System) piezoelectric cantilever device (PCD) for a fully cochlear implantable sensor that works within the audible frequency range of 300-4800 Hz. The sound pressure level (SPL) of 95 dB, 100 dB, and 110 dB input is given in order to resonates the audible frequency range of the device which is placed on the eardrum. This stimulates the auditory nerve via the cochlea to send information to the brain. As a result, the Multi-channel MEMS piezoelectric cantilever device generates the highest potential voltage of 870 mV at 110-dB SPL and is detected under the excitation of 300 Hz. The output parameters such as von Mises stress, displacement, and the complete frequency bandwidth performance are analyzed using COMSOL Multiphysics.

Correction factor of lumped parameter model for linearly tapered piezoelectric cantilever

Distributed parameter model (DPM) gives an accurate representation of the vibration response of piezoelectric cantilevers. Nevertheless, lumped parameter model (LPM) has been widely used because of its simple mathematical representation. However, researchers developed a correction factor for LPM because of its inaccurate power output prediction of the piezoelectric harvesters. The developed correction factors were limited to the rectangular and exponentially tapered piezoelectric beams because the DPM of other shaped beams are rather complicated to derive. This paper presents a correction factor for linearly tapered piezoelectric cantilever beam using a finite element model (FEM) approach. Validation of the developed FEM is accomplished using two analytical models from literature of rectangular and exponentially tapered shapes with tip mass. Results show an excellent agreement between the FEM and the related DPM. The FEM of a linearly tapered piezoelectric cantilever is then built and the error of using the uncorrected LPM for different tapered ratios is investigated. Correction factors of different taper ratios subjected to various tip masses are developed. Comparisons between the corrected LPM and the FEM verify the estimation of the correction factor. Results show that FEM approach can be used to enhance the accuracy of LPM of piezoelectric cantilever harvesters.

Geometry and shape optimization of piezoelectric cantilever energy harvester using COMSOL multiphysics software

In embedded systems that necessarily require a steady source of power and (or) attaches to a sensor(s), there are opportunities to mix small batteries to supply such power. The aim of this research is to optimize the geometry and shape of piezoelectric cantilevers to harvest more power. Several piezoelectric cantilever geometries with various shapes (rectangular, triangular, circular, and trapezoidal cross section) are tested in COMSOL multiphysics simulator to find the best geometry that provides the highest accomplishable power. The most efficient geometry was found to be conferred by the trapezoidal, cross section cantilever. Next, another improvement method was applied to maximize the harvested power of the cantilever by modifying the shape of the trapezoidal cantilever structure through increasing the number of its faces. The results demonstrated that the highest output power (36 mW) was produced by the four faces, trapezoidal cross section design of cantilever.

Horizontally Assembled Trapezoidal Piezoelectric Cantilevers Driven by Magnetic Coupling for Rotational Energy Harvester Applications

Horizontally assembled trapezoidal piezoelectric cantilevers driven by magnetic coupling were fabricated for rotational energy harvester applications. A dodecagonal rigid frame with an attached array of six trapezoidal cantilevers served as a stator for electrical power generation. A rotor disk with six permanent magnets (PMs) interacted magnetically with the counterpart cantilever’s tip-mass PMs of the stator by rotational motion. Each trapezoidal piezoelectric cantilever beam was designed to operate in a transverse mode that utilizes a planar Ag/Pd electrode printed onto lead zirconate titanate (PZT) piezoelectric thick film. The optimized distance between a pair of PMs of the rotor and the stator was evaluated as approximately 10 mm along the same vertical direction to make the piezoelectric cantilever beam most deflectable without the occurrence of cracks. The theoretically calculated resistance torque was maximized at 46 mN·m for the optimized trapezoidal piezoelectric cantilever. The proposed energy harvester was also demonstrated for wind energy harvester applications. Its harvested output power reached a maximum of approximately 22 mW at a wind speed of 10 m/s under a resistive load of 30 kΩ. The output performance of the proposed energy harvester makes it possible to power numerous low-power applications such as smart sensor systems.

Impact-driven piezoelectric energy harvester using a pendulum structure for low-frequency vibration

This study investigates a pendulum ball impact-excited piezoelectric energy harvester (PEH) for low frequency vibration through finite element analysis and experimental verification. This structure can harvest the vibration energy of infrasonic level, which provides a new idea for the energy harvest of low frequency. Experimental results show that for a pendulum ball impact-excited PEH with a 2.5 mm horizontal displacement excitation at 2 Hz, namely the sinusoidal excitation acceleration of 0.04 g, the collision frequency between the pendulum and the cantilevers reaches 10 Hz, and the open-circuit peak voltage of two piezoelectric cantilevers in the collision is 30.1 and 27.1 V respectively. Under the parallel connection of two piezoelectric cantilevers, the open-circuit peak voltage is 15.8 V and a maximum output power of 10.53 μW can be achieved across a 130 kΩ external load resistance. Compared with a single pendulum ball structure, a bi-pendulum ball structure can interact with two cantilever beams in one collision, thereby improving the efficiency of energy collection and reducing the optimal load resistance. A maximum output power of 43 μW can be achieved across a 47 kΩ external load resistance and 2 Hz rotational vibration excitation.

Optimizing Piezoelectric Cantilever Design for Electronic Nose Applications

This work demonstrates a method to optimize materials and dimensions of piezoelectric cantilevers for electronic nose applications via finite element analysis simulations. Here we studied the optimum piezoelectric cantilever configuration for detection of cadaverine, a biomarker for meat ageing, to develop a potential electronic nose for the meat industry. The optimized cantilevers were fabricated, characterized, interfaced using custom-made electronics, and tested by approaching meat pieces. The results show successful measurements of cadaverine levels for meat pieces with different ages, hence, have a great potential for applications within the meat industry shelf-life prediction.