scholarly journals Enhanced Energy Harvesting of Flexural Waves in Elastic Beams by Bending Mode of Graded Resonators

2021 ◽  
Vol 8 ◽  
Author(s):  
Jacopo Maria De Ponti ◽  
Luca Iorio ◽  
Emanuele Riva ◽  
Francesco Braghin ◽  
Alberto Corigliano ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Natural Frequencies ◽  
Elastic Beam ◽  
Flexural Waves ◽  
Vibration Energy Harvesting ◽  
Micro Fabrication ◽  
Wave Propagation Direction ◽  
Practical Applications ◽  
Bending Mode ◽  
Definition Of

We show efficient elastic energy transfer and wave confinement through a graded array of resonators attached to an elastic beam. Experiments demonstrate that flexural resonators of increasing lengths allow to reduce wave scattering and to achieve the rainbow effect with local wavefield amplifications. We show that the definition of a monotonically decreasing distribution of the natural frequencies of the resonators along the wave propagation direction, is the preferable choice to increase the energy efficiency of the system. The proposed configuration is suitable for micro-fabrication, envisaging practical applications for micro-scale vibration energy harvesting.

scholarly journals Analysis of Double Elastic Steel Wind Driven Magneto-Electric Vibration Energy Harvesting System

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7364
Author(s):  
Yi-Ren Wang ◽  
Ming-Ching Chu
Keyword(s):  
Energy Harvesting ◽  
Electric Energy ◽  
Elastic Beam ◽  
Electrical Energy ◽  
Vibration Energy ◽  
Vibration Energy Harvesting ◽  
Concentrated Load ◽  
Single Beam ◽  
Piezoelectric Patch ◽  
Energy Harvesting System

This research proposes an energy harvesting system that collects the downward airflow from a helicopter or a multi-axis unmanned rotary-wing aircraft and uses this wind force to drive the magnet to rotate, generating repulsive force, which causes the double elastic steel system to slap each other and vibrate periodically in order to generate more electricity than the traditional energy harvesting system. The design concept of the vibration mechanism in this study is to allow the elastic steel carrying the magnet to slap another elastic steel carrying the piezoelectric patch to form a set of double elastic steel vibration energy harvesting (DES VEH) systems. The theoretical DES VEH mechanism of this research is composed of a pair of cantilever beams, with magnets attached to the free end of one beam, and PZT attached to the other beam. This study analyzes the single beam system first. The MOMS method is applied to analyze the frequency response of this nonlinear system theoretically, then combines the piezoelectric patch and the magneto-electric coupling device with this nonlinear elastic beam to analyze the benefits of the system’s converted electrical energy. In the theoretical study of the DES VEH system, the slapping force between the two elastic beams was considered as a concentrated load on each of the beams. Furthermore, both SES and DES VEH systems are studied and correlated. Finally, the experimental data and theoretical results are compared to verify the feasibility and correctness of the theory. It is proven that this DES VEH system can not only obtain the electric energy from the traditional SES VEH system but also obtain the extra electric energy of the steel vibration subjected to the slapping force, which generates optimal power to the greatest extent.

Vibration Modeling of Arc-Based Cantilevers for Energy Harvesting Applications

2014 ◽  
Vol 1 (1-2) ◽  
Author(s):  
Daniel J. Apo ◽  
Mohan Sanghadasa ◽  
Shashank Priya
Keyword(s):  
Energy Harvesting ◽  
Low Frequency ◽  
Substrate Thickness ◽  
Cantilever Beams ◽  
Vibration Energy Harvesting ◽  
Low Frequency Vibration ◽  
Vibration Model ◽  
Bending Mode ◽  
Out Of Plane ◽  
Tip Mass

AbstractCantilever beams are widely used for designing transducers for low-frequency vibration energy harvesting. However, in order to keep the dimensions within reasonable constraints, a large tip mass is generally required for reducing the resonance frequency below 100 Hz which has adverse effect on the reliability. This study provides a breakthrough toward realizing low-frequency micro-scale transduction structures. An analytical out-of-plane vibration model for standalone arc-based cantilever beams was developed that includes provisions for shear and rotary inertia, multidirectional arcs, and multiple layers. The model was applied to a multilayered cantilever beam (10-mm wide and 0.1-mm thick) composed of three arcs, and the results indicate that the fundamental bending mode of the beam was 38 Hz for a silicon substrate thickness of 100 μm. The model was validated with modal experimental results from an arc-based cantilever made out of aluminum.

scholarly journals DEFINITION OF KINEMATICS OF DEFORMATION BASED ON SPLINE-APPROXIMATIONS

2020 ◽  
pp. 101-107
Author(s):  
Roman Sivak
Keyword(s):  
Function Approximation ◽  
Elastic Beam ◽  
Experimental Information ◽  
Random Errors ◽  
Polynomial Splines ◽  
Current Function ◽  
Practical Applications ◽  
Definition Of ◽  
Current Lines ◽  
Fixed System

It is suggested to use smoothing cubic spline functions to approximate the current functions. The structure of the selected functional provides the minimum curvature of the spline and the smallest deviation of the spline from the function smoothed at the nodes. The necessary correlation between these requirements is provided by the choice of weights. The algorithm for approximating the current function is implemented by moving from a grid created by current lines and auxiliary lines to a rectangular grid. To reduce the effect of random errors of experimental information on the current line, a smoothing algorithm with a given accuracy was used. The current function is interpolated from the physical grid to the calculated one. The flow velocities were approximated to calculate the strain rates. To estimate the accuracy of the calculations, it is proposed to use the deviation from the incompatibility condition. The main disadvantage is that their behavior around a point determines their behavior as a whole. In this regard, other approaches to the approximation free of this deficiency have been developed in recent years. One such approach that has proven itself well in both theoretical and practical applications is the use of so-called splines. Splines are called functions that are glued together from different pieces of polynomials by a fixed system. The simplest example is broken. Splines naturally occur in many mechanical problems. For example, the spline shape has an elastic beam with point loads. Among the splines, polynomial splines glued together from pieces of polynomials play the most important role. The development of the theory of such splines and their popularization were facilitated by I. Schoenberg's work. Polynomial splines are beginning to be used in many application problems related to function approximation.

Resolution and measurement in the scanning electron microscope

1987 ◽  
Vol 45 ◽  
pp. 534-537 ◽  
Author(s):  
Michael T. Postek
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Engineering Design ◽  
Resolving Power ◽  
Practical Applications ◽  
Instrument Resolution ◽  
Accurate Definition ◽  
Definition Of ◽  
Scanning Electron ◽  
Better Than

The term ultimate resolution or resolving power is the very best performance that can be obtained from a scanning electron microscope (SEM) given the optimum instrumental conditions and sample. However, as it relates to SEM users, the conventional definitions of this figure are ambiguous. The numbers quoted for the resolution of an instrument are not only theoretically derived, but are also verified through the direct measurement of images on micrographs. However, the samples commonly used for this purpose are specifically optimized for the measurement of instrument resolution and are most often not typical of the sample used in practical applications.SEM RESOLUTION. Some instruments resolve better than others either due to engineering design or other reasons. There is no definitively accurate definition of how to quantify instrument resolution and its measurement in the SEM.

scholarly journals Experiment Investigation of Bistable Vibration Energy Harvesting with Random Wave Environment

2021 ◽  
Vol 11 (9) ◽  
pp. 3868
Author(s):  
Qiong Wu ◽  
Hairui Zhang ◽  
Jie Lian ◽  
Wei Zhao ◽  
Shijie Zhou ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Energy Harvesting ◽  
Cantilever Beam ◽  
Large Scale ◽  
Low Frequency ◽  
Vibration Energy ◽  
Random Wave ◽  
Periodic Signal ◽  
Vibration Energy Harvesting ◽  
Motion Activity

The energy harvested from the renewable energy has been attracting a great potential as a source of electricity for many years; however, several challenges still exist limiting output performance, such as the package and low frequency of the wave. Here, this paper proposed a bistable vibration system for harvesting low-frequency renewable energy, the bistable vibration model consisting of an inverted cantilever beam with a mass block at the tip in a random wave environment and also develop a vibration energy harvesting system with a piezoelectric element attached to the surface of a cantilever beam. The experiment was carried out by simulating the random wave environment using the experimental equipment. The experiment result showed a mass block’s response vibration was indeed changed from a single stable vibration to a bistable oscillation when a random wave signal and a periodic signal were co-excited. It was shown that stochastic resonance phenomena can be activated reliably using the proposed bistable motion system, and, correspondingly, large-scale bistable responses can be generated to realize effective amplitude enlargement after input signals are received. Furthermore, as an important design factor, the influence of periodic excitation signals on the large-scale bistable motion activity was carefully discussed, and a solid foundation was laid for further practical energy harvesting applications.

Genetic algorithm- and finite element-based design and analysis of nonprismatic piezolaminated beam for optimal vibration energy harvesting

2015 ◽  
Vol 230 (14) ◽  
pp. 2532-2548 ◽  
Author(s):  
Alok Ranjan Biswal ◽  
Tarapada Roy ◽  
Rabindra Kumar Behera
Keyword(s):  
Genetic Algorithm ◽  
Finite Element ◽  
Energy Harvesting ◽  
Output Power ◽  
Governing Equation ◽  
Optimization Technique ◽  
Vibration Energy ◽  
Fe Model ◽  
Vibration Energy Harvesting ◽  
Real Coded Genetic Algorithm

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.

scholarly journals Response Identification in a Vibration Energy-Harvesting System with Quasi-Zero Stiffness and Two Potential Wells

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3926
Author(s):  
Joanna Iwaniec ◽  
Grzegorz Litak ◽  
Marek Iwaniec ◽  
Jerzy Margielewicz ◽  
Damian Gąska ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Recurrence Plot ◽  
Piezoelectric Transducers ◽  
Vibration Energy ◽  
Vibration Energy Harvesting ◽  
Potential Wells ◽  
Frequency Responses ◽  
Voltage Output ◽  
Quantification Analysis ◽  
Energy Harvesting System

In this paper, the frequency broadband effect in vibration energy harvesting was studied numerically using a quasi-zero stiffness resonator with two potential wells and piezoelectric transducers. Corresponding solutions were investigated for system excitation harmonics at various frequencies. Solutions for the higher voltage output were collected in specific branches of the power output diagram. Both the resonant solution synchronized with excitation and the frequency responses of the subharmonic spectra were found. The selected cases were illustrated and classified using a phase portrait, a Poincaré section, and recurrence plot (RP) approaches. Select recurrence quantification analysis (RQA) measures were used to characterize the discussed solutions.

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