A Comparative Study on the Primary System Response and Energy Harvesting from Linear and Nonlinear Tuned Vibration Absorbers

Author(s):  
P. V. Rasil Raj ◽  
B. Santhosh
2009 ◽  
Vol 62 (6) ◽  
Author(s):  
Lari Kela ◽  
Pekka Vähäoja

This article gathers together the most recent articles of adjustable tuned vibration absorbers. The tuned vibration absorber was invented over 100 years ago, and its adjustability is also already well-known. However, concentration of this review was only on articles published since the year 2000 in peer reviewed journals, except from certain elementary books and some previous review articles in order to keep up with the current events in this broad field. First a brief inspection of the theory of tuned vibration absorbers (TVAs) is presented. After that mechanical TVAs are presented more carefully. In the same chapter the following are also handled: virtual absorbers, absorbers with adjustable damping, and Helmholtz resonators. Own chapter is allocated for multiple TVAs whose idea is to replace adjustability by adding several TVAs to primary system to damp out vibrations in the wide frequency band. The review section is completed by presenting smart material TVAs, which include, e.g., piezoelectric materials, shape-memory alloys, electrorheological and magnetorheological materials of fluids. An adjustable Helmholtz resonator in a low pressure hydraulic system is presented in Sec. 5. Experiments verify the efficiency of the damping character of the adjustable Helmholtz resonator whose resonant frequency can be varied.


Actuators ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 119
Author(s):  
Luis Gerardo Trujillo-Franco ◽  
Gerardo Silva-Navarro ◽  
Francisco Beltran-Carbajal ◽  
Eduardo Campos-Mercado ◽  
Hugo Francisco Abundis-Fong

A solution of the vibration attention problem on a flexible structure from a dynamic vibration absorption perspective is experimentally and numerically studied in this article. Linear and nonlinear dynamic vibration absorbers are properly implemented on a primary structure of n degrees of freedom through a modal decomposition analysis and using the tuning condition when the primary system has one single degree of freedom. A time-domain algebraic identification scheme for on-line modal parameter estimation of flexible structures is presented. A fast frequency estimation of harmonic excitation force is also obtained. A Hilbert transform analysis of the frequency response function for the case of nonlinear dynamic vibration absorption is introduced. In this way, influence of this particular passive nonlinear control device on system dynamic response can be determined. The proposed approach is validated on an harmonically perturbed building-like structure, which is discretized in a finite number of degrees of freedom. The flexible structure is subjected to resonant operational conditions, and coupled to a pendulum vibration absorber configured as a tuned mass damper as well as an autoparametric system.


2019 ◽  
Vol 460 ◽  
pp. 114874 ◽  
Author(s):  
Aditya Suryadi Tan ◽  
Jimmy Aramendiz ◽  
Kanu Hughan Ross ◽  
Thomas Sattel ◽  
Alexander Fidlin

Author(s):  
Hieu Nguyen ◽  
Hamzeh Bardaweel

The work presented here investigates a unique design platform for multi-stable energy harvesting using only interaction between magnets. A solid cylindrical magnet is levitated between two stationary magnets. Peripheral magnets are positioned around the casing of the energy harvester to create multiple stable positions. Upon external vibration, kinetic energy is converted into electric energy that is extracted using a coil wrapped around the casing of the harvester. A prototype of the multi-stable energy harvester is fabricated. Monostable and bistable configurations are demonstrated and fully characterized in static and dynamic modes. Compared to traditional multi-stable designs the harvester introduced in this work is compact, occupies less volume, and does not require complex circuitry normally needed for multi-stable harvesters involving piezoelectric elements. At 2.5g [m/s2], results from experiment show that the bistable harvester does not outperform the monostable harvester. At this level of acceleration, the bistable harvester exhibits intrawell motion away from jump frequency. Chaotic motion is observed in the bistable harvester when excited close to jump frequency. Interwell motion that yields high displacement amplitudes and velocities is absent at this acceleration.


2006 ◽  
Vol 06 (02) ◽  
pp. 269-284 ◽  
Author(s):  
SUNNY K. GEORGE ◽  
K. SHANKAR

The distribution of vibrational energy in members of a complex structure with tuned absorbers attached at the joints and subjected to dynamic loading is studied. The concept of power flows through the structure is used to determine the time-averaged energy levels of each member in the structure. The power flows are calculated using the time-averaged product of force and velocity at the input and coupling points (joints) of a general structure made of axially vibrating rods. The receptance approach is used to calculate the coupling forces and velocities in the structure. By balancing the input power against the dissipated powers, the time-averaged energy levels in members are determined. The main criteria studied here is the reduction in the frequency-averaged vibrational energy level of a member when an absorber is attached, expressed as a percentage compared to the case where there are no absorbers. The concept is first illustrated with a simple model of 2 axially vibrating rods with an absorber attached to the joint. Next, a more complex structure comprising 8 rods with arbitrary orientations and several absorbers attached to junctions is studied. The effect of activating absorbers at various locations on reducing the energy levels of certain members is examined. It is possible to estimate the usefulness of the absorber with respect to any member by determining the percentage reduction of energy level for that member.


Author(s):  
Hashem Ashrafiuon

Abstract This paper presents the effect of foundation flexibility on the optimum design of vibration absorbers. Flexibility of the base is incorporated into the absorber system equations of motion through an equivalent damping ratio and stiffness value in the direction of motion at the connection point. The optimum values of the uncoupled natural frequency and damping ratio of the absorber are determined over a range of excitation frequencies and the primary system damping ratio. The design parameters are computed and compared for the rigid, static, and dynamic models of the base as well as different levels of base flexibility.


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