This paper presents a finite element (FE) model developed using commercial FE software COMSOL to simulate the multiphysical process of pieozoelectric vibration energy harvesting (PVEH), involving the dynamic mechanical and electrical behaviours of piezoelectric macro fibre composite (MFC) on carbon fibre composite structures. The integration of MFC enables energy harvesting, sensing and actuation capabilities, with applications found in aerospace, automotive and renewable energy. There is an existing gap in the literature on modelling the dynamic response of PVEH in relation to real-world vibration data. Most simulations were either semi-analytical MATLAB models that are geometry unspecific, or basic FE simulations limited to sinusoidal analysis. However, the use of representative environment vibration data is crucial to predict practical behaviour for industrial development. Piezoelectric device physics involving solid mechanics and electrostatics were combined with electrical circuit defined in this FE model. The structure was dynamically excited by interpolated vibration data files, while orthotropic material properties for MFC and carbon fibre composite were individually defined for accuracy. The simulation results were validated by experiments with

/pdf/multiphysics-vibration-fe-model-of-piezoelectric-macro-fibre-3qmx8saoks.pdf

Multiphysics vibration FE model of piezoelectric macro fibre composite on carbon fibre composite structures

Nonlinear dynamics of a new energy harvesting system with quasi-zero stiffness

The piezoelectric technique has received extensive attention in an energy harvesting system in the generation of electrical energy through renewable mechanical vibration. In this research paper, a bimorph energy scavenger based on the cantilever beam is designed and optimized to obtain the maximum efficiency. The COMSOL Multiphysics is utilized to design and simulate the proposed model whose output response has been investigated with the variation in the excitation frequency, the thickness of piezoelectric layers and the acceleration. It has been found that the thickness of the piezoelectric layers is the most promising parameter to acquire the maximum harvested energy. Moreover, several trials are also introduced in the simulation based on the resistance values of 20, 40, and 60 Ω. The results show that the output voltage has a positive linear relationship with the resistance and it is maximum at the frequency of 50 Hz, known as the resonant frequency. Many studies have shown quite significant relationships between mechanical vibration and harvested energy. So, the current research has presented a novice approach to optimize the results of an energy harvester. This approach is accomplished by a statistical analysis based on the Taguchi and ANOVA design of experiments.

Design and optimization of bimorph energy harvester based on Taguchi and ANOVA approaches

Optimization of piezoelectric energy harvester (PEH) to convert the ambient vibrational energy into maximum electrical energy has been of continued interest. The integration of the proof mass with the optimum cantilever width significantly enhances the output power of PEH. In this paper, we propose an optimized design of PEH that outperforms the existing AlN-based design in terms of power density. We analytically optimize the design of: 1) cantilever-to-harvester length and 2) cantilever-to-harvester width (proof mass width) ratios for the maximum output power. The optimized harvester is fabricated using a novel integration scheme for the bottom electrode with Au as an interlayer. The Au interlayer is used to grow a good quality of AlN film with piezoelectric coefficients, $d_{33} = 12$ pm/V and $d_{31} = -2.37 $ pm/V. It is found that in order to achieve the optimum output from PEH, the fractional length and width occupied by cantilever are 28%–40% and 38%–45%, respectively. The optimized designs are fabricated using a CMOS compatible process. The maximum power density measured from the fabricated PEHs is found to be 9.36 $\mu $ W/mm3, which is better than the similar reported data. The optimized and compact low-power PEHs reported in this paper have high potential to be integrated with the system on chip (SOC) and other wireless sensor applications.

High Power Density CMOS Compatible Micro-Machined MEMs Energy Harvester

The vast proliferation of wearables and smart sensing devices in the last decade has created an immense demand for new and efficient powering solutions. The research focus has shifted towards developing simple, cost-effective, flexible device topologies capable of capturing kinetic energy associated with the human body. Piezoelectric and triboelectric mechanisms are widely employed to convert biomechanical energy to electrical power due to their inherent merits in terms of affordable designs and high energy conversion efficiencies. In this work, we propose a flexible hybrid generator topology incorporating both piezoelectric and triboelectric mechanisms to achieve high electrical output from human motion. To enhance the efficiency and obtain a symmetric output, dual triboelectric generators are employed, which generate time-multiplexed output across the same set of electrodes. The device displays a characteristic ability to distinguish between different body movements as its output depends on the contact area as well as the pressure generated by the motion. This creates numerous avenues for employing the device in self-powered tactile sensing applications. The unique single substrate design makes the device robust and increases its longevity. The V-shaped prototype having an active area of 3.5 cm × 2 cm, is tested under a wide range of biomechanical stimuli, including touching, tapping, and pressing motions. The practical applications of the proposed device as an add-on patch on fabrics, as an in-sole device, and for powering commercial electronics are demonstrated. Apart from this, the reported generator can also fuel low-power devices from various other day-to-day human activities.

Flexible V-shaped piezoelectric-triboelectric device for biomechanical energy harvesting and sensing

https://cyberleninka.org/article/n/1411991.pdf

Modeling and Simulation of a Piezoelectric Vibration Energy Harvester

This paper presents modification in the thickness profile of bimorph cantilever type piezoelectric vibration energy harvester (PVEH) to achieve uniform stress along the beam length. The thickness profile is obtained by varying the thickness of substrate layer and keeping the thickness of piezoelectric layers constant. Analytical expressions for the cantilever beam displacement, stress on the beam and generated voltage are derived and solved for sinusoidal input excitations. The results from the analytical expressions are validated with that of the finite element (FE) analysis of an identical PVEH. The generated power and stress distribution in the proposed PVEH are compared with that of an equivalent conventional PVEH of uniform thickness. Compared to the conventional PVEH, in the proposed PVEH the generated power is 20% higher for an input acceleration of 0.2g, and the stress on the proposed device is found to be uniformly distributed with the peak stress value reduced significantly by 46%.

Piezoelectric vibration energy harvester with tapered substrate thickness for uniform stress

Micro-Electro-Mechanical-Systems (MEMS) devices and sensors have become an integral part of our daily life. From mobile phones to smart systems, there is a great demand of MEMS devices integrated with electronic circuits. Therefore, the design of an efficient MEMS devices has become of paramount importance. The design tools used in simulation of MEMS devices suffer from various issues, such as accuracy, time complexity, complex geometries etc. which need to be addressed in an efficient manner. Commercial tools used for MEMS device design are very costly and still provide limited scope for research and development. In this paper, a 2D framework is presented to simulate MEMS devices using Finite Element Method (FEM) as the discretization method. The proposed simulator can also be used to incorporate new mathematical models and is envisaged to enable academia and industry to work freely towards delivering efficient MEMS devices. FEM is used to discretize essential device equations, and later analyzed by using a suitable numerical methodology to find the solution. Displacement of a cantilever beam is obtained by using proposed MEMS simulator and is compared with the results obtained using COMSOL.

Sushanta Kundu

Papers

Modeling and Simulation of a Piezoelectric Vibration Energy Harvester

Piezoelectric vibration energy harvester with tapered substrate thickness for uniform stress

Design of a next generation framework for MEMS devices