Dynamic Vibration Absorber

About: Dynamic Vibration Absorber is a research topic. Over the lifetime, 4764 publications have been published within this topic receiving 49429 citations.

Investigation and optimization of nonlinear pendulum vibration absorber for horizontal vibration suppression of damped system

Abstract: Summary Nonlinear pendulum vibration absorber is investigated in this paper to control resonance peak of linear primary system with horizontal vibrations subjected to forced and motion excitations Pendulum vibration absorbers have been utilized as tuned mass damper for many years, but by this knowledge, nonlinear analysis of this problem has not been investigated anywhere Harmonic balance (HB) method is used to solve nonlinear differential equations and analyze the stability of their results Optimum damping and natural frequency ratios are derived by minimizing the maximum steady-state response of primary system with numerical optimization The presented analysis shows that the pendulum absorber design based on linear model resulting in a small area around the original frequency for vibration absorption For linear pendulum design, with a small deviation from the linear range, the amplitude of initial system greatly increased, and its performance will fall sharply But if the design is based on a nonlinear pendulum with larger amplitude of motion, the resulting design will have a higher accuracy In this paper, responses with inferior periods are inspected beside main period one Different methods are used for optimized nonlinear pendulum Finally, system robustness and chance of bifurcation will be predicted Copyright © 2015 John Wiley & Sons, Ltd

On the Vibration Isolation of Flexible Structures

Abstract: Although the study of vibration isolation has a very long history, when an isolated structure is so flexible that it cannot be properly approximated with a rigid body or a single-degree-of-freedom model, its vibration isolation brings about some new questions and problems. By transforming the dynamic equation of motion of the coupled structure formed by the isolator and the isolated structure into the modal space and following the tradition of studying features of the vibration transmissibility across the isolator, questions and problems associated with the flexible structure vibration isolation are studied. It is found from the study that a lower isolation frequency and a higher damping level can both increase the isolation effectiveness, the isolated structure is a vibration absorber to the isolator, and a combination of the vibration isolation and the vibration attenuation can be more effective in mitigating the vibration. A numerical example of the whole spacecraft vibration isolation has proved the above conclusions.

Proportional and derivative control for steady-state vibration mitigation in a piecewise linear beam system

Abstract: A control using Proportional and/or Derivative feedback (PD-control) is applied on a piecewise linear beam system with a flushing one-sided spring element for steady-state vibration amplitude mitigation. Two control objectives are formulated: (1) minimize the transversal vibration amplitude of the midpoint of the beam at the frequency where the first harmonic resonance occurs, (2) achieve this in a larger (low) excitation frequency range, where the lowest nonlinear normal mode dominates the response. Experimentally realizable combinations of PD-control are evaluated for both control objectives. Eventually objective (1) is realized by applying proportional control only, whereas derivative control is selected to realize objective (2). The vibration reduction that is achieved in simulations and validated by experiments is very significant for both objectives. Current results obtained with active PD-control are compared with earlier results obtained using a passive dynamic vibration absorber.

Optimization of an acoustic black hole vibration absorber at the end of a cantilever beam

Abstract: Structures whose thickness follow a power law profile exhibit the “acoustic black hole” (ABH) effect and can be used for effective vibration reduction. However, it is difficult to know a priori what constitutes the best design. A new block matrix formulation of the transfer matrix method is developed for use in the optimization of an ABH vibration absorber at the end of a cantilever beam. Results indicate that introduction of the ABH significantly alters the dynamics of the beam, which must be considered in determining the optimal design for a given vibration reduction problem.Structures whose thickness follow a power law profile exhibit the “acoustic black hole” (ABH) effect and can be used for effective vibration reduction. However, it is difficult to know a priori what constitutes the best design. A new block matrix formulation of the transfer matrix method is developed for use in the optimization of an ABH vibration absorber at the end of a cantilever beam. Results indicate that introduction of the ABH significantly alters the dynamics of the beam, which must be considered in determining the optimal design for a given vibration reduction problem.

Selectively tuned vibration absorber

Abstract: A selectively tuned vibration absorber comprising a stack of viscoelastic polymer damping plates, secured together with spacers at both ends and having metal tuning weights attached onto the topmost plate in the stack. The apparatus is secured to the low frequency drive unit of an in-wall loudspeaker with a metal mounting plate between the vibration absorber and the low frequency drive unit. Both ends of the vibration absorber are cantilevered over a tuning mounting plate centered between the ends of the unit, the degree of cantilever and the mass in the metal weights added to the topmost damping plate being variable such that the vibration absorber may be tuned to resonate at the fundamental resonance frequency of the low frequency drive unit.