Evaluation of Analytical and Finite Element Modeling on Coupled Field Dynamics of Piezoelectric Cantilever Bimorph Harvester

2013 ◽  
Vol 284-287 ◽  
pp. 1846-1850 ◽  
Author(s):  
Long Zhang ◽  
Keith A. Williams ◽  
Zheng Chao Xie

As the portable electronics and wireless sensors continue to be minimized in size and power consumption, the energy harvesting from the surrounding environment has become a potential major or supplementary power source for those devices. As an energy harvesting option for converting the mechanical vibrations to the electrical energy, the structure-electricity field coupled piezoelectric materials have relatively high conversion efficiency, light weight and small size, making them preferable for wireless sensor networks and portable electronics. In this paper, the modeling work on coupled field dynamics of the piezoelectric cantilevered bimorph (PCB) energy harvester is presented, in terms of structure tip displacement and open-circuit electrical potential generated through harmonic excitation. First, a single degree of freedom (SDOF) analytical model is presented for predicting the tip displacement of the PCB structure, and then a finite element (FE) model is created to simulate the tip displacement and open-circuit voltage of the PCB structure. Then, both the analytical and finite element models are compared against the laboratory experimental results. The comparison shows that the FE model has a better agreement with the experimental result than the analytical model. Based on the evaluation, these two models could be adopted as design tools in different cases.

Author(s):  
Alok Ranjan Biswal ◽  
Tarapada Roy ◽  
Rabindra Kumar Behera

The current article deals with finite element (FE)- and genetic algorithm (GA)-based vibration energy harvesting from a tapered piezolaminated cantilever beam. Euler–Bernoulli beam theory is used for modeling the various cross sections of the beam. The governing equation of motion is derived by using the Hamilton's principle. Two noded beam elements with two degrees of freedom at each node have been considered in order to solve the governing equation. The effect of structural damping has also been incorporated in the FE model. An electric interface is assumed to be connected to measure the voltage and output power in piezoelectric patch due to charge accumulation caused by vibration. The effects of taper (both in the width and height directions) on output power for three cases of shape variation (such as linear, parabolic and cubic) along with frequency and voltage are analyzed. A real-coded genetic algorithm-based constrained (such as ultimate stress and breakdown voltage) optimization technique has been formulated to determine the best possible design variables for optimal harvesting power. A comparative study is also carried out for output power by varying the cross section of the beam, and genetic algorithm-based optimization scheme shows the better results than that of available conventional trial and error methods.


Author(s):  
José Renato M. de Sousa ◽  
Carlos Magluta ◽  
Ney Roitman ◽  
George C. Campello

This work focuses on the structural analysis of a damaged 9.13″ flexible pipe to pure and combined axisymmetric loads. A set of experimental tests was carried out considering one up to ten broken wires in the outer tensile armor of the pipe and the results obtained are compared to those provided by a previously presented finite element (FE) model and a traditional analytical model. In the experimental tests, the pipe was firstly subjected to pure tension and, then, the responses to clockwise and anti-clockwise torsion superimposed with tension were investigated. In these tests, the induced strains in the outer armor were measured. Moreover, the axial elongation of the pipe was monitored when the pipe is subjected to tension, whilst the twist of the pipe was measured when torsion is imposed. The experimental results pointed to a slight decrease in the stiffness of the pipe with the increasing number of broken wires and, furthermore, a redistribution of forces among the intact wires of the damaged layer with high stress concentration in the wires close to the damaged ones. Both theoretical models captured these features, but, while the results obtained with the FE model agreed well with the experimental measurements, the traditional analytical model presented non-conservative results. Finally, the results obtained are employed to estimate the load capacity of the pipe.


Author(s):  
V. S. N. Ranjith Kumar ◽  
S. Kumar ◽  
G. Pal ◽  
Tushar Shah

Design of high-performance power lines with advanced materials is indispensable to effectively eliminate losses in electrical power transmission and distribution (T&D) lines. In this study, aluminum conductor composite core with carbon nanostructure (ACCC–CNS) coating in a multilayered architecture is considered as a novel design alternative to conventional aluminum conductor steel-reinforced (ACSR) transmission line. In the multiphysics approach presented herein, first, electrothermal finite element analysis (FEA) of the ACSR line is performed to obtain its steady-state temperature for a given current. Subsequently, the sag of the ACSR line due to self-weight and thermal expansion is determined by performing thermostructural analysis employing an analytical model. The results are then verified with those obtained from the FEA of the ACSR line. The electrothermal finite element (FE) model and the thermostructural analytical model are then extended to the ACCC–CNS line. The results indicate that the ACCC–CNS line has higher current-carrying capacity (CCC) and lower sag compared to those of the ACSR line. Motivated by the improved performance of the ACCC–CNS line, a systematic parametric study is conducted in order to determine the optimum ampacity, core diameter, and span length. The findings of this study would provide insights into the optimal design of high-performance overhead power lines.


Author(s):  
R. P. Hennessy ◽  
G. G. Adams ◽  
N. E. McGruer

This paper presents a finite element method approach for modeling a thermal-electrical-mechanical coupled-field contact comprised of an elastic hemisphere and an elastic half space. The goal of this model is to develop a fundamental understanding of the behavior of a multi-physics contact with a particular interest in the contact area. The results from the model illustrate a clear difference in contact behavior between force control and displacement control in the presence of an applied electrical potential. It is shown that, while Hertzian contact theory can be used to accurately predict the behavior of the contact under force control, a new relationship must be established to accurately predict the behavior of the contact under displacement control. This relationship can be applied to RF MEMS switch contact bumps as well as macro scale electrical contacts.


Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7370
Author(s):  
Asan G. A. Muthalif ◽  
Abdelrahman Ali ◽  
Jamil Renno ◽  
Azni N. Wahid ◽  
Khairul A. M. Nor ◽  
...  

Mechanical energy is the most ubiquitous form of energy that can be harvested and converted into useful electrical power. For this reason, the piezoelectric energy harvesters (PEHs), with their inherent electromechanical coupling and high-power density, have been widely incorporated in many applications to generate power from ambient mechanical vibrations. However, one of the main challenges to the wider adoption of PEHs is how to optimize their design for maximum energy harvesting. In this paper, an investigation was conducted on the energy harvesting from seven piezoelectric patch shapes (differing in the number of edges) when attached to a non-deterministic laminated composite (single/double lamina) plate subjected to change in fiber orientation. The performance of the PEHs was examined through a coupled-field finite element (FE) model. The plate was simply supported, and its dynamics were randomized by attaching randomly distributed point masses on the plate surface in addition to applying randomly located time-harmonic point forces. The randomization of point masses and point force location on a thin plate produce non-deterministic response. The design optimization was performed by employing the ensemble-responses of the electrical potential developed across the electrodes of the piezoelectric patches. The results present the optimal fiber orientation and patch shape for maximum energy harvesting in the case of single and double lamina composite plates. The results show that the performance is optimal at 0° or 90° fiber orientation for single-lamina, and at 0°/0° and 0°/90° fiber orientations for double-lamina composites. For frequencies below 25 Hz, patches with a low number of edges exhibited a higher harvesting performance (triangular for single-lamina/quadrilateral for double-lamina). As for the broadband frequencies (above 25 Hz), the performance was optimal for the patches with a higher number of edges (dodecagonal for single-lamina/octagonal for double-lamina).


Author(s):  
Vu Quang Viet ◽  
Hoang Ha ◽  
Pham Thai Hoan

In this study, the ultimate bending moment of circular concrete-filled double skin steel tubes (CFDSTs) was investigated. A CFDSTs made of two concentric circular steel tubes with concrete infill and M16 shear connector system was fabricated. The four-point bending test of the 10 m long CFDST consisting of outer and inner steel tubes with 914.4 mm and 514.4 mm in diameter, respectively, was carried out and the ultimate bending moment of the CFDST was investigated. A finite element (FE) simulation of the CFDSTs subjected to bending was developed using the commercial software ABAQUS and the accuracy of the developed FE model was verified by comparing to the experimental result. The ultimate bending moment of CFDSTs was then evaluated with respect to different concrete infill compressive strengths and yield strengths of the steel tubes. The corresponding design ultimate bending moments of the CFDST with regard to the design codes AISC and EC4 were also computed. The results revealed that EC4 and AISC can accurately predict the ultimate moment capacities of the CFDST with shear connector. Keywords: ultimate bending moment; concrete-filled double skin tube; shear connector system; finite element analysis. Received 19 November 2018, Revised 04 January 2019, Accepted 04 January 2019


Author(s):  
Qingzhen Lu ◽  
Zhixun Yang ◽  
Jun Yan ◽  
Hailong Lu ◽  
Jinlong Chen ◽  
...  

Umbilical is an important equipment in the subsea production to supply a connection between the floater and the subsea well. Analyzing strength and fatigue behaviors under bending is a key requirement to assure safety. An analytical model is proposed for predicting the bending behavior of a steel tube wounded helically around a frictionless cylinder. A full three-dimensional (3D) finite element (FE) model of an umbilical is developed by considering the frictions and contacts among its components. The numerical results of the bending stress of a steel tube were validated against that of the analytical model. The impacts of friction coefficients on the bending stress, contact pressure, and friction stress have been further investigated by the established FE model.


Author(s):  
R. D. Palhade ◽  
V. B. Tungikar ◽  
G. M. Dhole ◽  
S. M. Kherde

Transmission of high power at high voltages over very long distances has become very imperative. At present, throughout the globe, this task performed by overhead transmission lines. The dual task of mechanically supporting and electrically isolating the live phase conductors from the support tower is performed by insulators. The electrical potential, field and temperature distribution along the insulators governs the possible effects, which is quite detrimental to the system. However, a reliable data on electrical potential, field and temperature distribution in commonly employed insulators are rather scarce or access individually for thermal or electrical load only. Considering this, the present work has made an attempt to study accurately, thermal and electrical characteristics of 11 kV single cap and pin type ceramic disc distribution insulator assembly used for high voltage transmission. The coupled field thermo electrical finite element by using commercially available FEM software Ansys-11 is employed for the required field computations. This new set of ANSYS coupled-field elements enables users to accurately and efficiently analyze thermoelectric devices. This paper review the finite element formulation, which in addition to Joule heating, includes Seebeck, Peltier, Thomson effects and electrical load, i. e. by considering thermal and electric loads acting simultaneously. The Electrical voltage, electrical field and temperature distribution is deduced and compared with various other/individual analyses.


2019 ◽  
Vol 17 (06) ◽  
pp. 1950012
Author(s):  
Guangwei Meng ◽  
Liheng Wang ◽  
Qixun Zhang ◽  
Shuhui Ren ◽  
Xiaolin Li ◽  
...  

A coupled thermal–electrical–mechanical inhomogeneous cell-based smoothed finite element method (CICS-FEM) is presented for the multi-physics coupling problems, the displacements, the electrical potential and the temperature are obtained by combining the modified Wilson-[Formula: see text] method. By introducing the gradient smoothing technique into the FE model, the system stiffness of the model is reduced. In addition, due to the absence of mapping, CICS-FEM is insensitive to mesh distortion. Curves and contour plots of displacements, electrical potential and temperature of three FGP structures are given in the article. The results shows that CICS-FEM possesses several advantages: (i) insensitive to mesh distortion; (ii) reduce the system stiffness; (iii) convergent and accuracy; (iv) efficient than FEM when the results are at the same accuracy.


2014 ◽  
Vol 894 ◽  
pp. 167-171 ◽  
Author(s):  
Khairul Salleh Basaruddin ◽  
Naoki Takano

This study presents a prediction of apparent elastic moduli of vertebral trabecular bone using the homogenization method. A micro-finite element (FE) model of trabecular bone was reconstructed from a sequential of cross-section micro-CT image by converting bone voxels to brick elements. Eight regions of interest (ROIs) were extracted from two lumbar vertebra bone specimens of healthy and osteoporotic. The homogenization method and finite element method was employed to analyze the microscopic trabecular bone. Bone tissue property was modeled as orthotropy material considering the biological apatite (BAp) crystallite orientation. This research focuses on the effect of morphological difference between healthy and osteoporotic bones to the apparent elastic moduli. The change of degree of anisotropy was also discussed. Comparison of the calculated Youngs moduli in vertical axis with Keyak et al.s experimental result showed good agreement and proved the reliability of the numerical model.


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