scholarly journals Frequency-Adaptable Tuned Mass Damper Using Metal Cushions

Vibration ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 77-90
Author(s):  
Sebastian Rieß ◽  
William Kaal ◽  
Kristian Herath
Keyword(s):  
Dynamic Properties ◽  
Temperature Stability ◽  
Tuned Mass Damper ◽  
Nonlinear Springs ◽  
Input Amplitude ◽  
Damping Characteristics ◽  
Mass Damper ◽  
Viscous Mass ◽  
Amplitude Dependency ◽  
Stiffness And Damping

A frequency-adaptable tuned mass damper (FATMD) using metal cushions as tuneable stiffness components is presented. The dynamic properties of the cushions with respect to stiffness and damping are investigated experimentally in this context. The natural frequency of the experimental FATMD is found to be dependent on the precompression of the metal cushions, which behave like nonlinear springs, yielding an adjustable frequency range from 67 to 826 Hz. As the precompression is increased, the stiffness increases while the damping characteristics decrease, the effect of which was quantified using a viscous mass damper model as a first approximation. Measurements have been carried out under five different excitation amplitudes to investigate the amplitude dependency of the resonance frequency. The FATMD was largely unaffected by changes in input amplitude. It was concluded that metal cushions show great potential for use in FATMDs, surpassing the utility of elastomers, especially with respect to their temperature stability.

Dynamic Identification of 280mm Diameter Tilting Pad Journal Bearings: Test Results and Measurement Uncertainties Assessment of Different Designs

2020 ◽  
Author(s):  
Riccardo Ferraro ◽  
Alice Innocenti ◽  
Mirko Libraschi ◽  
Michele Barsanti ◽  
Enrico Ciulli ◽  
...  
Keyword(s):  
High Performance ◽  
Dynamic Properties ◽  
Journal Bearings ◽  
Turbulent Regime ◽  
Dynamic Identification ◽  
Damping Characteristics ◽  
Flexible Rotors ◽  
Tilting Pad ◽  
Stiffness And Damping ◽  
Tilting Pad Journal Bearings

Abstract Tilting pad journal bearings (TPJBs) are crucial elements in turbomachinery applications providing stiffness and damping characteristics that determine rotor system dynamic behavior. Hence, a correct design and an accurate dynamic properties prediction is fundamental for the successful industrial operation of rotating machinery. Current design trends in turbomachinery aiming at higher efficiency and power through weight optimization and higher operating speeds determine the development of large flexible rotors that are particularly important from the rotordynamic standpoint. The dynamic feasibility of this type of machine relies on bearing stiffness and damping characteristics that must be predicted with a certain level of confidence in order to increase the accuracy of the expected rotordynamic behaviour and avoid unpredicted vibration issues when rotors are operated. Furthermore, large centrifugal compressors commonly used in Liquified Natural Gas (LNG) applications make the bearings operate at very high peripheral speed where the transition from laminar to turbulent regime occurs, increasing the necessity of predictions accuracy. In this paper a test campaign on different large TPJB solutions operating in turbulent lubrication regime has been performed on a dedicated test rig designed for investigations on large size high-performance oil bearings. In the present work both static performance and dynamic identification of the tested TPJB solutions are presented and compared to numerical model predictions. The results of an uncertainty quantification, performed to validate the experimental results, are also shown.

Improvement of tuned mass damper by using rotational inertia through tuned viscous mass damper

2013 ◽  
Vol 56 ◽  
pp. 2149-2153 ◽  
Author(s):  
Hernán Garrido ◽  
Oscar Curadelli ◽  
Daniel Ambrosini
Keyword(s):  
Tuned Mass Damper ◽  
Rotational Inertia ◽  
Mass Damper ◽  
Viscous Mass

Estimation of Dynamic Properties of Tuned Mass Damper in Service

2021 ◽  
Vol 25 (2) ◽  
pp. 49-54
Author(s):  
Jae-Seung Hwang ◽  
◽  
Si-Yun Kim ◽  
Seung-Woo Lee
Keyword(s):  
Dynamic Properties ◽  
Tuned Mass Damper ◽  
Mass Damper

A hybrid approach for parameter optimization of multiple tuned mass dampers in reducing floor vibrations due to occupant walking: Theory and parametric studies

2017 ◽  
Vol 20 (8) ◽  
pp. 1232-1246 ◽  
Author(s):  
Ruotian Xu ◽  
Jun Chen ◽  
Xinqun Zhu
Keyword(s):  
Dynamic Properties ◽  
Damping Ratio ◽  
Hybrid Approach ◽  
Tuned Mass Damper ◽  
Dynamic Responses ◽  
Optimization Approach ◽  
Tuned Mass Dampers ◽  
Mass Damper ◽  
Floor Vibrations ◽  
Multiple Tuned Mass Dampers

This article presents a hybrid approach for determining optimal parameters of multiple tuned mass dampers to reduce the floor vibration due to human walking. The proposed approach consists of two parts. The first one is a partial mode decomposition algorithm to efficiently calculate dynamic responses of the coupled floor–multiple tuned mass damper system subjected to moving walking loads. The second one is an adaptive genetic simulated annealing method for the optimization of multiple tuned mass damper parameters. To establish optimization, certain variables must be considered. These include the mass, natural frequency, and damping ratio of each tuned mass damper in a multiple tuned mass damper system. The objective is to minimize floor responses and remove unreasonable requirements, such as uniform mass distribution and symmetric distribution of the tuned mass damper frequency. The proposed hybrid approach has successfully been applied to optimize the multiple tuned mass damper system to reduce the vibration of a long-span floor with closely spaced modes. By the hybrid approach, an extensive parametric study has been carried out. The results show that different walking load models and uncertainties in the dynamic properties of the floor and each tuned mass damper itself can affect the overall performance of the multiple tuned mass damper system. The proposed hybrid optimization approach is very effective and the resulting multiple tuned mass damper system is robust in reducing floor vibrations under various conditions.

scholarly journals A parametric study of a tower controlled by a pendulum tuned mass damper: beam modelling

2018 ◽  
Vol 211 ◽  
pp. 14006
Author(s):  
Gino B. Colherinhas ◽  
Maura A. M. Shzu ◽  
Suzana M. Avila ◽  
Marcus V. G. de Morais
Keyword(s):  
Parametric Study ◽  
Structural Control ◽  
Structural Model ◽  
Tuned Mass Damper ◽  
Fe Model ◽  
Genetic Optimization ◽  
Mass Damper ◽  
Element Type ◽  
Stiffness And Damping Coefficient ◽  
Stiffness And Damping

This paper models a tower with a passive Pendulum Tuned Mass Damper (PTMD) with Finite Elements (FE) using the resources and capabilities of commercial software ANSYS. Although structural control of high and slender towers using PTMDs are widely studied in literature, it was not found yet studies modelling the PTMD with ANSYS. This FE model is called by a routine coded in MATLAB to find the relation between the mass, length, stiffness, and damping coefficient of the pendulum in function of the high vibration amplitudes at the top of the tower (defined as a beam element type). This parametric study of the dynamic behaviour of the PTMD + FE beam structural model is analysed and its results are compared to a genetic optimization developed in other researches to find the best pendulum parameters.

PROPERTIES OF AN INTERCONNECTED HYDRO-PNEUMATIC SUSPENSION SYSTEM

1995 ◽  
Vol 19 (4) ◽  
pp. 383-396 ◽  
Author(s):  
P.J. Liu ◽  
S. Rakheja ◽  
A.K.W. Ahmed
Keyword(s):  
Dynamic Properties ◽  
The Body ◽  
Ride Quality ◽  
Quality Performance ◽  
Fundamental Properties ◽  
Damping Characteristics ◽  
Load Carrying ◽  
Body Roll ◽  
Pneumatic Suspension ◽  
Stiffness And Damping

The static and dynamic properties of a vehicle suspension comprising hydraulic struts interconnected in the roll plane are investigated. The fundamental properties of the interconnected suspension are investigated and compared to those of the unconnected suspensions with and without the anti-roll bar, in terms of load-carrying capacity, suspension rate, roll stiffness as well as damping characteristics. The anti-roll performance of the interconnected suspension is analyzed for excitations encountered during directional manoeuvres. The ride quality performance is evaluated for excitations occurring at tire-road interface. It is concluded that the interconnected hydro-pneumatic suspension with inherent enhanced roll stiffness and damping characteristics can significantly restrict the body roll motion to achieve improved roll stability of a vehicle.

Prediction of Solutions of the Duffing System with Tuned Mass Damper

2020 ◽  
Vol 22 (4) ◽  
pp. 983-990
Author(s):  
Konrad Mnich
Keyword(s):  
Dynamical System ◽  
Duffing Oscillator ◽  
Probabilistic Approach ◽  
Nonlinear Dynamical System ◽  
Tuned Mass Damper ◽  
Nonlinear Dynamical ◽  
Duffing System ◽  
Mass Damper ◽  
Basin Stability ◽  
Stability Concept

AbstractIn this work we analyze the behavior of a nonlinear dynamical system using a probabilistic approach. We focus on the coexistence of solutions and we check how the changes in the parameters of excitation influence the dynamics of the system. For the demonstration we use the Duffing oscillator with the tuned mass absorber. We mention the numerous attractors present in such a system and describe how they were found with the method based on the basin stability concept.

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