Energy harvesting dynamic vibration absorber under random vibration

Author(s):  
S. Dipak ◽  
M. Rajarathinam ◽  
S. F. Ali
2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Xiaoling Jin ◽  
M. Z. Q. Chen ◽  
Zhilong Huang

This paper concentrates on the random vibration suppression of a regular straight beam by using an inerter-based dynamic vibration absorber. For a wideband random point-driven straight beam with an inerter-based dynamic vibration absorber, the distribution of mean-square velocity response along the axis of the straight beam as well as the mean kinetic energy of the whole beam are first analytically derived through the classical linear random vibration theory. Two optimization objectives are established to determine the optimal design parameters: (1) minimizing the maximal mean-square velocity along the axis of the straight beam, which corresponds to the maximal mean kinetic energy density along the axis and (2) minimizing the mean kinetic energy of the whole beam. Numerical search gives the optimal location and the associated optimal parameters of the inerter-based dynamic vibration absorber. Numerical results for a simply supported straight beam illustrate the better performance of an inerter-based dynamic vibration absorber than a traditional dynamic vibration absorber. Parametric sensitivity studies for the robustness analysis of the beam response to deviations from the optimal parameters are conducted. The optimal location locates on the force-excited point, while the suboptimal location locates on its symmetry position. Furthermore, the optimal and suboptimal locations remain invariable regardless of the upper cutoff frequency of band-limited noise, which is fairly important to the location optimization of the inerter-based dynamic vibration absorber.


2013 ◽  
Vol 80 (4) ◽  
Author(s):  
Shaikh Faruque Ali ◽  
Sondipon Adhikari

Energy harvesting is a promise to harvest unwanted vibrations from a host structure. Similarly, a dynamic vibration absorber is proved to be a very simple and effective vibration suppression device, with many practical implementations in civil and mechanical engineering. This paper analyzes the prospect of using a vibration absorber for possible energy harvesting. To achieve this goal, a vibration absorber is supplemented with a piezoelectric stack for both vibration confinement and energy harvesting. It is assumed that the original structure is sensitive to vibrations and that the absorber is the element where the vibration energy is confined, which in turn is harvested by means of a piezoelectric stack. The primary goal is to control the vibration of the host structure and the secondary goal is to harvest energy out of the dynamic vibration absorber at the same time. Approximate fixed-point theory is used to find a closed form expression for optimal frequency ratio of the vibration absorber. The changes in the optimal parameters of the vibration absorber due to the addition of the energy harvesting electrical circuit are derived. It is shown that with a proper choice of harvester parameters a broadband energy harvesting can be obtained combined with vibration reduction in the primary structure.


Author(s):  
Agathoklis Giaralis

Abstract This paper examines the performance of a regenerative dynamic vibration absorber, dubbed energy harvesting-enabled tuned mass-damper-inerter (EH-TMDI), for vibration suppression and energy harvesting in white noise excited damped linear primary structures. Single-degree-of-freedom (SDOF) structures under force and base excitations are studied as well as multi-degree-of-freedom (MDOF) structures under correlated random forces. The EH-TMDI includes an electromagnetic motor (EM), behaving as a shunt damper, sandwiched between a secondary mass and an inerter element connected in series. The latter element resists relative acceleration through a constant termed inertance which is readily scalable in actual inerter devices. In this regard, attention is herein focused on gauging the available energy for harvesting by the EM and the displacement variance of the primary structure as the inertance increases through comprehensive parametric investigations. This is supported by adopting inertance-dependent tuning formulae for the EH-TMDI stiffness and damping properties and closed-form expressions for the response of white-noise excited EH-TMDI-equipped SDOF and MDOF systems derived through random vibration theory. It is found that lightweight EH-TMDIs, having 1% the mass of the primary structure, achieve simultaneously improved vibration suppression and energy harvesting performance as inertance amplifies. For SDOF structures with grounded inerter, the improvement rate is higher for reduced inherent structural damping and increased EM shunt damping. For MDOF structures with non-grounded inerter, improvement rate is higher as the primary structure flexibility between the two EH-TMDI attachment points increases.


Author(s):  
M Rajarathinam ◽  
Shaikh Faruque Ali

Abstract An energy harvesting dynamic vibration absorber is studied to suppress undesirable vibrations in a host structure as well as to harvest electrical energy from vibrations using piezoelectric transduction. The present work studies the feasibility of using vibration absorber for harvesting energy under random excitation and in presence of parametric uncertainties. A two degrees of freedom model is considered in the analytical formulation for the host along with the absorber. A separate equation is used for energy generation from piezoelectric material. Two studies are reported here, (i) with random excitation where the base input is considered to be Gaussian; (ii) parametric uncertainty is considered with harmonic excitation. Under random base excitation the analytical results show that, with the proper selection of parameters, harvested electrical energy can be increased along with the reduction in vibration of the host structure. Graphs are reported showing trade-off between harvested energy and vibration control. Whereas, Monte Carlo simulations are carried out to analyze the system with parametric uncertainty. This showed that the mean harvested power decreases with an increase in uncertainties in the natural frequency as well as damping ratio. In addition, optimal electrical parameters for obtaining maximum power for the case of uncertain parameters are also reported in this study.


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