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1

Behaviour of a torsional vibration viscous damper in the event of a damper fluid shortage

Chmielowiec Andrzej, Michajłyszyn Adam, Homik Wojciech

Polish Maritime Research

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2023

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nr 2

105--113

EN

This article presents the analysis of a damping fluid deficiency in a torsional vibration viscous damper. The problem is analysed both qualitatively and quantitatively. Experimental results are presented, showing what happens to the damper in a situation where the design of the housing is inadequate and the inertia forces prevent the formation of an oil film. In addition, the article deals with the problem of the proper design of the oil channel and the dimensions required to enable the damper to operate reliably. The results of the article may be useful to the constructors of torsional vibration viscous dampers for marine engines.

2

Optimal retrofit strategy using viscous dampers between adjacent RC and SMRFs prone to earthquake‑induced pounding

Asgarkhani N., Kazemi F., Jankowski R.

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 1

art. no. e7, 2023

EN

Nowadays, retrofitting-damaged buildings is an important challenge for engineers. Finding the optimal placement of Viscous Dampers (VDs) between adjacent structures prone to earthquake-induced pounding can help designers to implement VDs with optimizing the cost of construction and achieving higher performance levels for both structures. In this research, the optimal placement of linear and nonlinear VDs between the 3-story, 5-story, and 9-story Steel and RC Moment-Resisting Frames (SMRFs and RC MRFs) is investigated. It is shown that the pounding phenomenon can significantly affect the seismic performance capacities of buildings during earthquakes, and using VDs can improve the seismic limit-state capacities of buildings for retrofitting purposes. For this goal, the seismic limit-state capacities of both colliding structures were assessed using Incremental Dynamic Analysis (IDA) assuming Near-fault Pulse-Like, Near-fault No-Pulse, and Far-Fault seismic records suggested by FEMA-P695. To perform IDAs, structures were modeled according to the seismic codes using a developed algorithm in Matlab and OpenSees software with the ability to remove a collapsed structure during the analysis. The results present an optimal placement for using VDs between structures and also compare the possible conditions to implement VDs. Using these results, engineers can approximately predict the seismic performance levels of both structures prone to earthquake-induced pounding and their final performance after retrofitting. Finally, retrofitting modification factors were proposed to help designers to predict the limit-state performance levels of retrofitted colliding structures without involving complicated and time-consuming analyses.

3

Numerical studies of suspension system with double spring loaded using the force pulse

Krason W., Wysocki J.

Journal of KONES

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2018

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Vol. 25, No. 1

241--248

EN

The forced vibration of a dependent rear suspension model of the two-axle vehicle, equipped with a 3D model of a double spring and a viscous shock absorber is the subject of consideration. The clearance between the master and auxiliary springs is a specificity of the double suspension construction. Dynamic analysis of such a system has been performed by forcing with different forms of force pulses using the fixed base of force 10 kN. Three different time runs (two trapezoidal and one triangular model) are used as the force impulses. Modelling and analysis taking into consideration contact problems have been developed using the MSC.Software package with a special use of Patran pre-processor and Nastran solver. A finite element method (FEM) has been used in numerical analysis of the suspension model with geometric nonlinearities, viscous damping [9] and time-varying load. The boundary conditions of numerical models correspond to a spring support in the real vehicle suspension. The non-periodic damped vibrations and damped free vibrations of the simplified suspension system are investigated during numerical analysis. Selected results of the model tests have been presented in the form of the timings of the accelerations of the spring elements and of the forces in the suspension damper.

4

Dobór tłumików wiskotycznych do tłumienia drgań skrętnych wałów korbowych silników spalinowych

Jagiełowicz-Ryznar C.

Autobusy : technika, eksploatacja, systemy transportowe

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2018

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R. 19, nr 6

482--485, CD

PL

W pracy przedstawiono metodę doboru tłumika wiskotycznego na podstawie badania współczynnika tłumienia wiskotycznego tłumika drgań skrętnych. Podstawą metody są pomiary wymuszonych drgań skrętnych wału pomiarowego z tłumikiem na specjalnym stanowisku badawczym. Na podstawie wzoru teoretycznego uwzględniając wyniki pomiarów drgań wyznaczono współczynnik tłumienia.

EN

The method of viscous damper fitting, on the base of damping factor of viscous torsion damper, was presented in this paper. The measurements of forced torsional vibration of measuring shaft with damper, on the special test bench are the basis of the method. According to the theoretical formula, including the results of the vibrations measuring, the damping coefficient was determined.

5

The evaluation of the reduction of seismic response of adjacent structures using viscous damper joints

Malek H. K., Emami K.

Advances in Science and Technology. Research Journal

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2017

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Vol. 11, no 3

31--47

EN

This study examines the effects of common viscose damper on the behavior of adjacent reinforced concrete structures. For this purpose, three reinforced concrete buildings with 3, 5 and 7 floors and a regular plan were selected and were compared in two cases with and without viscous dampers at the seams. They are designed based on discussions of Buildings Regulations 2800 and the 6 and 9 issues of Iranian National Building Regulations. Those buildings that were under the analysis of accelerograms of Bam, Mangil and El Centro, are then analyzed with nonlinear modal time history. The accelerograms before applied to the structures are scaled based on the 2800 Regulations. Those buildings were modeled by SAP2000 finite element modeling software. Linear behavior of structural components of said structure and the non-linear behavior of viscous dampers were modeled. Finally, the seismic response of the buildings includes the base shear force, up to a maximum lateral acceleration of seismic classes. Classes for both with and without the viscous damper have been extracted and compared. The results showed the reduction in relative lateral displacement, maximum acceleration and base cut applied to a structure in the presence of viscous dampers between two structures. This decline is not even in the direction that the viscous damper is viewed as significant.

6

The impact of complex forcing on the viscous torsional vibration damper’s work in the crankshaft of the rotating combustion engine

Jagiełowicz-Ryznar C.

International Journal of Applied Mechanics and Engineering

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2016

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Vol. 21, no. 4

1017--1023

EN

The numerical calculations results of torsional vibration of the multi-cylinder crankshaft in the serial combustion engine (MC), including a viscous damper (VD), at complex forcing, were shown. In fact, in the MC case the crankshaft rotation forcings spectrum is the sum of harmonic forcing whose amplitude can be compared with the amplitude of the 1st harmonic. A significant impact, in the engine operational velocity, on the vibration damping process of MC, may be the amplitude of the 2nd harmonic of a forcing moment. The calculations results of MC vibration, depending on the amplitude of the 2nd harmonic of the forcing moment, for the first form of the torsional vibration, were shown. Higher forms of torsional vibrations have no practical significance. The calculations assume the optimum damping coefficient VD, when the simple harmonic forcing is equal to the base critical velocity of the MC crankshaft.

7

Badania wiskotycznych tłumików drgań skrętnych wału korbowego silnika spalinowego

Jagiełowicz-Ryznar C.

Przegląd Mechaniczny

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2015

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nr 5

35--38

PL

W artykule przedstawiono problematykę sprawdzenia przydatności do dalszej eksploatacji wiskotycznych tłumików drgań skrętnych. Na specjalnie utworzonym stanowisku badawczo-pomiarowym ustalono charakterystyki amplitudowo-częstotliwościowe, na podstawie których oceniono stan techniczny tłumików.

EN

The usefulness testing of the viscous torsional vibration dampers to the further exploitation is the issue of this paper. On the specially created research work station the amplitude-frequency characteristics, being the base to assess the dampers technical

8

Proposal of a new group of magnetorheological dampers

Minorowicz B., Stefański F.

Przegląd Elektrotechniczny

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2014

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R. 90, nr 7

263--267

EN

The article presents a construction and testing of a new family of magnetorheological dampers. The work began with testing currently used solutions, which exist inter alia in vibratory machines for example in washing machines. Basis on this job required damping parameters were obtained and then these parameters were used as input data in new devices designing process. A distinguishing feature of newly designed dampers is considerably reduction of volume of smart liquid in comparison to existing solutions described in the literature.

PL

W artykule przedstawiono budowę i badania nowej rodziny tłumików magnetoreologicznych. Prace rozpoczęto od przeprowadzenia badań obecnie wykorzystywanych konstrukcji tłumików wiskotycznych, które stosowane są między innymi w maszynach wibracyjnych na przykład w pralkach automatycznych. W wyniku przeprowadzonych badań ustalono wymagane parametry tłumienia i użyto ich, jako danych wejściowych w procesie projektowania nowego urządzenia. Charakterystyczną cechą nowo zaprojektowanych tłumików jest znacznie zmniejszenie objętości stosowanych cieczy inteligentnych w stosunku do istniejących rozwiązań, opisanych w literaturze.

9

Metryka wiskotycznego tłumika drgań skrętnych

Homik W.

Zeszyty Naukowe Akademii Marynarki Wojennej

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2013

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R. 54 nr 1 (192)

55--66

PL

W artykule opisano zagadnienia związane z procesem wzbudzania drgań skrętnych układów napędowych jednostek pływających, a także metody ich tłumienia. Skoncentrowano się głównie na metodzie pośredniej — zastosowaniu tłumika wiskotycznego, opisując jego „metrykę” zawierającą podstawowe parametry konstrukcyjne, fizyczne oraz charakterystyki amplitudowo-częstotliwościowe.

EN

In this paper discussed are the problems concerned with the induction of torsional vibrations in the ships drive systems as well as dampingmethods. The main focus of attentions is the indirect method an application of viscotic damper through its ‘certificate description’, which includes the basic construction and physical parameters and amplitude-frequency characteristics

10

Application of the polynomial chaos approximation to a stochastic parametric vibrations problem

Brząkała A.

Archives of Civil and Mechanical Engineering

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2013

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Vol. 13, no. 2

220--228

EN

In the paper the application of the polynomial chaos expansion in case of parametric vibrations problem is presented. Hitherto this innovative approach has not been applied to such a stochastic problem. The phenomenon is described by a nonlinear ordinary differential equation with periodic coefficients. It can be observed among others in cable-stayed bridges due to periodic excitation caused by a deck or a pylon. The analysis is focused on a real situation for which the problem of parametric resonance was observed (a cable of the Ben–Ahin bridge). The characteristic of the viscous damper is considered as a log-normal random variable. The results obtained by the use of the polynomial chaos approximations are compared with the ones based on the Monte Carlo simulation. The convergence of both methods is discussed. It is found that the polynomial chaos yields a better convergence then the Monte Carlo simulation, if resonant vibrations appear.

11

Analysis of vibrations of the simplified model of the suspension system with a double spring and a fluid damper

Krasoń W., Wysocki J.

Journal of KONES

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2011

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Vol. 18, No. 1

311-316

EN

The subject of the paper are forced vibrations of the rear suspension of the biaxial vehicle fitted with the double spring spatial shell model and the viscous damper, under the force pulse input with the given transient response. The play between the master and auxiliary spring is a specific feature of the double spring design [1, 6]. Numerical tests were taken for three variants of the viscous attenuation. The attenuation coefficient values for typical dependent suspensions and their range of changes were assumed on the basis of publication [14]. The problem of modelling and analysing, including contact issues, was solved with the use of the MSC Software programme package with the special use of MSC Patran pre-processor [12]. The numerical analysis of the suspension model with the geometrical nonlinearities, viscous attenuation, and time-varying load was taken with the use of the finite element method (FEM). The selected results of the model tests in the form of the suspension relative displacements (speeds) and deformations (stresses) for the selected points of the master and auxiliary spring against time are presented in the paper. The complete model of the suspension system makes possible to examine the influence of various inputs on the interoperation and the phenomena associated with the dynamic response of such a complex system.