A Linear-Element Coupled Nonlinear Energy Harvesting System

Author(s):  
Shengxi Zhou ◽  
Daniel J. Inman ◽  
Junyi Cao

This paper presents a linear-spring coupled nonlinear energy harvesting system, which contains linear piezoelectric energy harvesters coupled by linear springs. Although every element of the system is linear, the system will present nonlinear characteristics when it is subjected to excitations because of the geometric nonlinearity induced by coupled motions. Three non-uniform cross-section linear harvesters with the same total length and the different thickness are selected to form the proposed system. Based on Euler-Bernoulli beam assumptions and the geometrical relationship among each element, a detailed modeling process of the proposed system is presented. In order to verify the broadband characteristics, the comparison of the proposed system and its linear counterparts is provided. Under harmonic excitations, the proposed system has much better energy harvesting capacity compared with its linear counterparts. What’s more, the energy harvesting performance of the proposed system is a little better than its linear counterparts under random excitations. The results demonstrate that the advantage of the proposed system is enhanced along with increased excitation level. In addition, such non-magnetic nonlinear energy harvesting system can be used in the areas where magnets are forbidden, such as inside the human body.

2014 ◽  
Vol 953-954 ◽  
pp. 655-658 ◽  
Author(s):  
Guang Qing Shang ◽  
Hong Bing Wang ◽  
Chun Hua Sun

Energy harvesting system has become one of important areas of ​​research and develops rapidly. How to improve the performance of the piezoelectric vibration energy harvester is a key issue in engineering applications. There are many literature on piezoelectric energy harvesting. The paper places focus on summarizing these literature of mathematical modeling of piezoelectric energy harvesting, ranging from the linear to nonlinear, from early a single mechanical degree to piezoaeroelastic problems.


2009 ◽  
Vol 79-82 ◽  
pp. 103-106 ◽  
Author(s):  
Li Hua Tang ◽  
Yao Wen Yang

Accurate modeling and computer aided simulation is advantageous during the design stage of a piezoelectric energy harvesting system. In this paper, system-level finite element modeling (FEM) of a cantilevered piezoelectric energy harvester with a resistor is conducted using ANSYS. Considering that practical energy harvesting circuit includes nonlinear electrical elements, which is beyond the modeling capability of ANSYS, an equivalent circuit modeling (ECM) method is proposed to address the problem. After the parameters of equivalent circuit are identified, system-level simulation is conducted in SPICE software.


Author(s):  
Virgilio J Caetano ◽  
Marcelo A Savi

Energy harvesting from ambient vibration through piezoelectric devices has received a lot of attention in recent years from both academia and industry. One of the main challenges is to develop devices capable of adapting to diverse sources of environmental excitation, being able to efficiently operate over a broadband frequency spectrum. This work proposes a novel multimodal design of a piezoelectric energy harvesting system to harness energy from a wideband ambient vibration source. Circular-shaped and pizza-shaped designs are employed as candidates for the device, comparing their performance with classical beam-shaped devices. Finite element analysis is employed to model system dynamics using ANSYS Workbench. An optimization procedure is applied to the system aiming to seek a configuration that can extract energy from a broader frequency spectrum and maximize its output power. A comparative analysis with conventional energy harvesting systems is performed. Numerical simulations are carried out to investigate the harvester performances under harmonic and random excitations. Results show that the proposed multimodal harvester has potential to harness energy from broadband ambient vibration sources presenting performance advantages in comparison to conventional single-mode energy harvesters.


Author(s):  
Sumin Seong ◽  
Christopher Mullen ◽  
Soobum Lee

This paper presents reliability-based design optimization (RBDO) and experimental validation of the purely mechanical nonlinear vibration energy harvester we recently proposed. A bi-stable characteristic was embodied with a pre-stressed curved cantilever substrate on which piezoelectric patches were laminated. The curved cantilever can be simply manufactured by clamping multiple beams with different lengths or by connecting two ends of the cantilever using a coil spring. When vibrating, the inertia of the tip mass activates the curved cantilever to cause snap-through buckling and makes the nature of vibration switch between two equilibrium positions. The reliability-based design optimization study for maximization of power density and broadband energy harvesting performance is performed. The benefit of the proposed design in terms of excellent reliability, design compactness, and ease of implementation is discussed. The prototype is fabricated based on the optimal design result and energy harvesting performance between the linear and nonlinear energy harvesters is compared. The excellent broadband characteristic of the purely mechanical harvester will be validated.


2013 ◽  
Vol 52 (10S) ◽  
pp. 10MB03 ◽  
Author(s):  
Hyun Jun Jung ◽  
Daniel Song ◽  
Seong Kwang Hong ◽  
Yooseob Song ◽  
Tae Hyun Sung

Author(s):  
Jesse J. French ◽  
Colton T. Sheets

Wind energy capture in today’s environment is often focused on producing large amounts of power through massive turbines operating at high wind speeds. The device presented by the authors performs on the extreme opposite scale of these large wind turbines. Utilizing vortex induced vibration combined with developed and demonstrated piezoelectric energy harvesting techniques, the device produces power consistent with peer technologies in the rapidly growing field of micro-energy harvesting. Vortex-induced vibrations in the Karman vortex street are the catalyst for energy production of the device. To optimize power output, resonant frequency of the harvester is matched to vortex shedding frequency at a given wind speed, producing a lock-on effect that results in the greatest amplitude of oscillation. The frequency of oscillation is varied by altering the effective spring constant of the device, thereby allowing for “tuning” of the device to specific wind environments. While localized wind conditions are never able to be predicted with absolute certainty, patterns can be established through thorough data collection. Sampling of local wind conditions led to the design and testing of harvesters operating within a range of wind velocities between approximately 4 mph and 25 mph. For the extremities of this range, devices were constructed with resonant frequencies of approximately 17 and 163 Hz. Frequency variation was achieved through altering the material composition and geometry of the energy harvester. Experimentation was performed on harvesters to determine power output at optimized fluid velocity, as well as above and below. Analysis was also conducted on shedding characteristics of the device over the tested range of wind velocities. Computational modeling of the device is performed and compared to experimentally produced data.


Author(s):  
Saman Farhangdoust ◽  
Claudia Mederos ◽  
Behrouz Farkiani ◽  
Armin Mehrabi ◽  
Hossein Taheri ◽  
...  

Abstract This paper presents a creative energy harvesting system using a bimorph piezoelectric cantilever-beam to power wireless sensors in an IoT network for the Sunshine Skyway Bridge. The bimorph piezoelectric energy harvester (BPEH) comprises a cantilever beam as a substrate sandwiched between two piezoelectric layers to remarkably harness ambient vibrations of an inclined stay cable and convert them into electrical energy when the cable is subjected to a harmonic acceleration. To investigate and design the bridge energy harvesting system, a field measurement was required for collecting cable vibration data. The results of a non-contact laser vibrometer is used to remotely measure the dynamic characteristics of the inclined cables. A finite element study is employed to simulate a 3-D model of the proposed BPEH by COMSOL Multiphasics. The FE modelling results showed that the average power generated by the BPEH excited by a harmonic acceleration of 1 m/s2 at 1 Hz is up to 614 μW which satisfies the minimum electric power required for the sensor node in the proposed IoT network. In this research a LoRaWAN architecture is also developed to utilize the BPEH as a sustainable and sufficient power resource for an IoT platform which uses wireless sensor networks installed on the bridge stay cables to collect and remotely transfer bridge health monitoring data over the bridge in a low-power manner.


Author(s):  
Yangyang Zhang ◽  
Bingwei Lu ◽  
Chaofeng Lü ◽  
Xue Feng

Self-powered implantable devices with flexible energy harvesters are of significant interest due to their potential to solve the problem of limited battery life and surgical replacement. The flexible electronic devices made of piezoelectric materials have been employed to harvest energy from the motion of biological organs. Experimental measurements show that the output voltage of the device mounted on porcine left ventricle in chest closed environment decreases significantly compared to the case of chest open. A restricted-space deformation model is proposed to predict the impeding effect of pleural cavity, surrounding tissues, as well as respiration on the efficiency of energy harvesting from heartbeat using flexible piezoelectric devices. The analytical solution is verified by comparing theoretical predictions to experimental measurements. A simple scaling law is established to analyse the intrinsic correlations between the normalized output power and the combined system parameters, i.e. the normalized permitted space and normalized electrical load. The results may provide guidelines for optimization of in vivo energy harvesting from heartbeat or the motions of other biological organs using flexible piezoelectric energy harvesters.


2008 ◽  
Vol 20 (5) ◽  
pp. 625-632 ◽  
Author(s):  
Yonas Tadesse ◽  
Shujun Zhang ◽  
Shashank Priya

In this study, we report a multimodal energy harvesting device that combines electromagnetic and piezoelectric energy harvesting mechanism. The device consists of piezoelectric crystals bonded to a cantilever beam. The tip of the cantilever beam has an attached permanent magnet which, oscillates within a stationary coil fixed to the top of the package. The permanent magnet serves two purpose (i) acts as a tip mass for the cantilever beam and lowers the resonance frequency, and (ii) acts as a core which oscillates between the inductive coils resulting in electric current generation through Faraday's effect. Thus, this design combines the energy harvesting from two different mechanisms, piezoelectric and electromagnetic, on the same platform. The prototype system was optimized using the finite element software, ANSYS, to find the resonance frequency and stress distribution. The power generated from the fabricated prototype was found to be 0.25 W using the electromagnetic mechanism and 0.25 mW using the piezoelectric mechanism at 35 g acceleration and 20 Hz frequency.


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