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1

Exploiting gyroscopic effects for resonance elimination of an elastic rotor utilizing only one piezo actuator

Jungblut Jens, Franz Daniel, Fischer Christian, Rinderknecht Stephan

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 6

art. no. e147060

EN

A gyroscopic rotor exposed to unbalance and internal damping is controlled with an active piezoelectrical bearing in this paper. The used rotor test-rig is modelled using an FEM approach. The present gyroscopic effects are then used to derive a control strategy which only requires a single piezo actuator, while regular active piezoelectric bearings require two. Using only one actuator generates an excitation which contains an equal amount of forward and backward whirl vibrations. Both parts are differently amplified by the rotor system due to gyroscopic effects, which cause speed-dependent different eigenfrequencies for forward and backward whirl resonances. This facilitates eliminating resonances and stabilize the rotor system with only one actuator but requires two sensors. The control approach is validated with experiments on a rotor test-rig and compared to a control which uses both actuators.

2

Effects of grid disturbances on current source rectifier controlled by FCS-MPC algorithm

Godlewska A.

Power Electronics and Drives

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2018

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Vol. 3 (38), No. 1

11--22

EN

Nowadays, the increasing number of non-linear loads influences the grid, causing grid voltage disturbances. These disturbances may be very dangerous for the equipment and can create faults in converter behaviour. However, the right control algorithm can improve the reliability of the work. For a current source rectifier, the finite control set model predictive control has been proposed. This method is very flexible because of the variety of the possible cost function forms. It has been examined under grid voltage disturbed by the higher harmonics and the voltage drop. Simulation results prove the ability to damp the distortions and to ensure the unity power factor. Summing up, the algorithm is a very good solution for use in applications such as battery charging, active power filtering and low-voltage direct current load feeding.

3

Aktywne tłumienie siedzenia pojazdu specjalnego

Tengler S., Warwas K.

Modelowanie Inżynierskie

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2016

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T. 28, nr 59

86--91

PL

W pracy przedstawiono sposób doboru optymalnego tłumienia fotela kierowcy pojazdu specjalnego, który bezpośrednio przyczynia się do zwiększenia komfortu jazdy. Model matematyczny pojazdu sformułowano, korzystając ze współrzędnych złączowych i przekształceń jednorodnych. Przedstawiono manewr przejazdu przez przeszkodę w postaci progu zwalniającego. Przedmiotem badań było dobranie takiego tłumienia fotela kierowcy, aby zminimalizować amplitudy drgań występujące w tym podukładzie. Do rozwiązania zadania wykorzystano dwie gradientowe metody optymalizacji o różnej złożoności numerycznej. Przedstawiono i porównano wyniki otrzymane w procesie optymalizacji. Z uwagi na długi czas potrzebny na uzyskanie wyników z optymalizacji dynamicznej zaproponowano sztuczną sieć neuronową, która po poprawnym wytrenowaniu może być stosowana w procesach czasu rzeczywistego.

EN

This paper presents a method of selecting the optimal damping of the driver's special vehicle seat which contributes directly to improved ride comfort. A mathematical model of the vehicle was formulated using the joint coordinates and homogenous transformations. A maneuver of the vehicle passing over obstacle in the form of speed bump was presented. The object of the research was to select such damping of the driver's seat to minimize vibrations encountered in this subsystem. In order to solve the problem two gradient optimization methods of varying numerical complexity were used. The results obtained in the process of optimization were presented and compared. Due to the long time needed to obtain results of the dynamic optimization the neural network, which after properly training may be used in the real time process, was proposed.

4

Continuous and discrete sliding mode control of an active car suspension system

Łuczko J., Ferdek U.

Journal of Theoretical and Applied Mechanics

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2016

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Vol. 54 nr 1

3--11

EN

In this paper, sliding mode control (SMC) algorithms are tested for their use in an active car suspension system. Using the quarter model of the car as an example, the comparison of the efficiency of the algorithms is made. A continuous and two discrete versions of the sliding mode control are taken into consideration. The study is limited to finding the relation between the control parameters and the comfort factor. This is done by analyzing the response of the model to the harmonic and impulse excitation.

5

Numerical Study of Forced Vibration Suppression by Parametric Anti-Resonance

Pešek L., Šulc P., Půst L.

Archives of Acoustics

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2016

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Vol. 41, No. 3

527--533

EN

The parametric anti-resonance phenomenon as an active damping tool for suppression of externally excited resonant vibration is numerically studied herein. It is well known fact that the anti-resonance phenomenon, i.e. the stiffness periodic variation by subtractive, combination resonance frequency, brings stabilization and cancelling into self-excited vibrations. But this paper aims at a new possibility of its application, namely a damping of externally excited resonant vibration. For estimation of its effect we come both from a characteristic exponent of the analytical solution and numerical solution of forced vibration of 2DOF linear system with additional parametric excitation. The amplitude suppression owing to the parametric anti-resonance is studied on several parameters of the system: a depth of parametric excitation, mass ratio, damping coefficient and small frequency deviations from the parametric anti-resonance.

6

Performance comparison of active and semi-active SMC and LQR regulators in a quarter-car model

Ferdek U., Łuczko J.

Journal of Theoretical and Applied Mechanics

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2015

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Vol. 53 nr 4

811—822

EN

In this paper, an analysis is performed on a quarter-car model of car suspension with semi- -active and active damper utilizing the sliding mode (SMC) and linear-quadratic control (LQR). The effect of control parameters and time delays in the transmission of control signal on the factors related to the safety and comfort of driving is investigated. The results obtained from numerical simulations are shown in form of frequency characteristics for several selected performance factors.

7

Application of Piezofilms for Excitation and Active Damping of Blade Flexural Vibration

Pešek L., Půst L., Bula V., Cibulka J.

Archives of Acoustics

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2015

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Vol. 40, No. 1

59--69

EN

The steam turbine blades of low pressure stages are endangerd by the high-cyclic fatigue due to the combined loading of dynamic stresses by the steam time-variant pressure and the pre-stress from centrifugal forces. Therefore, the importance of their experimental dynamic analysis in the design stage is critical. For laboratory tests of the blades, the piezo actuators placed on the blades, unlike electromagnets placed in the stationary space, give a possibility to excite the flexural vibration of the blades within the bladed disk by time continuous forces independently of the rotor revolutions. In addition, the piezo actuators can be also used to control the vibrations of the blade. Therefore, several dynamic experiments of the clamped model blade equipped with PVDF films were performed for the force description of the piezo foils and their behavior as actuators of the blade vibration. The numerical beam models were used for numerical analysis of the vibration suppression effects both by additional parametric excitation and by active damping. The optimal phase shift of piezo actuator voltage supply was ascertained both for amplitude amplification and suppression. The results contribute to the knowledge of the actuation and active damping of blade vibration by the piezo elements.

8

Tłumienie aktywne dyskretnych mechatronicznych układów drgających

Białas K., Gałęziowski D.

Modelowanie Inżynierskie

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2013

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T. 16, nr 47

36--40

PL

W pracy zbadano wpływ zastosowania dodatkowego tłumienia aktywnego na charakterystyki dynamiczne mechatronicznych układów dyskretnych. Rozpatrywane układy mechatroniczne składają się z dyskretnych mechanicznych modeli połączonych z piezoaktuatorami typu „stack” oraz z zewnętrznymi obwodami elektrycznymi LRC. Porównano wpływ tłumików aktywnych na charakterystyki amplitudowo-częstotliwościowe i podatność przy różnych konfiguracjach działania elementu piezoelektrycznego z układem elektrycznym LRC. Wyniki przedstawiono w postaci wykresów. Układy zaprojektowano w wyniku rozwiązania zadania odwrotnego do analizy, ze względu na obrane wymagania w postaci częstości rezonansowych i antyrezonansowych. Problem opisano na podstawie wybranych przykładów obliczeniowych.

EN

In this paper influence of application of additional active damping on dynamical characteristics of mechatronic discrete systems has been studied. Considered mechatronic structures have been built from discrete mechanical models connected to piezostack actuators and external electric LRC networks. The impact of active damping elements on amplitude frequency response function and dynamical flexibility, within different configurations of piezo function with LRC networks, have been compared and presented in graph form. Systems have been designed by solving the reverse task to analysis, in relations to known and established criteria in form of resonant and antiresonant frequencies. Problem has been presented basing on selected calculations examples.

9

Numerical Investigation of Piezoelectric Element Coupling Degradation in Active Beam Systems

Freundlich J. K., Pietrzakowski M.

Machine Dynamics Research

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2013

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Vol. 37, No. 4

13-26

EN

The objective of the present study is to develop modelling of the piezoelectric element edge delamination process and analysis of effects of the progressive adhesive interlayer damage on active beam dynamic behaviour. In the considered system piezoelectric patches are mounted to both opposite sides of the beam and operate as a collocated sensor/actuator pair with velocity feedback. Herein, the actuator coupling damage is described as a large reduction of the adhesive interlayer shear stiffness. It is assumed that the damaged zone of the decreased stiffness extends uniformly across the actuator from its edges to the centre. In the analysis, the beam is divided into sections due to its geometry and the supposed delaminated regions. The calculations are performed using the FE analysis. In the first step, the cantilever beam with piezoelectric elements bonded to the beam surface by a thin glue layer of uniform properties is analysed. The beam is excited by a time varying force. In order to validate the arranged FE model, the analytical and FE calculations of open and closed loop dynamic responses are performed. The compared results show quite good agreement and prove that the applied FE model of the considered system is correct and can be accepted for further numerical analysis. In the next step, FE simulations of the beam forced vibration suppressed by piezoelectric control system with velocity feedback are accomplished. The influence of the length of damaged zone on the dynamic characteristics and the control effectiveness is investigated. As expected, the size, type and location of the coupling damage influence on the dynamic characteristics of the examined beam and cause reduction of the system control efficiency.

10

Stabilization of a fluid structure interaction with nonlinear damping

Lasiecka I., Lu Y.

Control and Cybernetics

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2013

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Vol. 42, no. 1

155--181

EN

Asymptotic stability of finite energy solutions to a fluid-structure interaction with a static interface in a bounded domain Ω ∈ Rn, n = 2 is considered. It is shown that the undamped model subject to ”partial flatness” geometric condition on the in- terface produces solutions whose energy converges strongly to zero; while with a stress type feedback control applied on the interface of the structure, the model produces solutions whose energy is exponentially stable. An addition of a static damping on the interface produces solutions whose full norm in the phase space is exponentially stable. Without a static damping an interesting phenomenon occurs that steady state solutions (equilibria) might generate genuinely growing in time solutions. This is purely nonlinear phenomenon captured by newly developed techniques amenable to handle instability of steady state solutions arising from nonlinearity.

11

Analiza MES w sterowaniu drganiami belki za pomocą elementów piezoelektrycznych

Freundlich J., Hoffman G., Pietrzakowski M.

Symulacja w Badaniach i Rozwoju

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2012

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Vol. 3, nr 4

185--194

PL

W pracy przedstawiono symulacje MES swobodnych i wymuszonych drgań belki, aktywnie tłumionych układem elementów piezoelektrycznych pracujących z prędkościowym sprzężeniem zwrotnym. Zbadano dwa modele układu – model bez i z uwzględnieniem warstwy kleju mocującej elementy piezoelektryczne do konstrukcji głównej. W celu pokazania efektywności tłumienia drgań obliczenia wykonano dla kilku wartości współczynnika wzmocnienia w pętli sprzężenia zwrotnego. Symulacje wykazały widoczną różnicę amplitud otrzymanych z obliczeń przy zastosowaniu obu modeli. Wartości amplitud drgań w przypadku modelu z uwzględnieniem warstw kleju są znacznie mniejsze niż te otrzymane przy użyciu modelu z doskonałym połączeniem czujnika i aktuatora z belką.

EN

FE simulations of the beam free and forced vibration suppressed by piezoelectric control system with velocity feedback are accomplished. Two models of examined system are considered - the model without and with taking account of a glue layer connecting piezoelectric transducers to the main structure. Several control gain values are used in calculations to show active damping effects. The calculations demonstrate noticeable difference between calculated amplitudes using both models. Amplitude values obtained using the model with glue layers are noticeable lower than that obtained for the perfectly bonded sensor/actuator patches.

12

Sieciowy przekształtnik prądowy PWM z aktywnym tłumieniem obwodu wejściowego

Płatek T., Rąbkowski J.

Przegląd Elektrotechniczny

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2010

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R. 86, nr 4

258-265

PL

W artykule przedstawiono analizę właściwości trójfazowego przekształtnika sieciowego PWM z obwodem wyjściowym o charakterze źródła prądu stałego z punktu widzenia współpracy z siecią o odkształconym napięciu. Główny nacisk położono na dobór parametrów filtru sieciowego LC oraz analizę wpływu aktywnego tłumienia filtru wejściowego na kształt przebiegu wartości chwilowej prądu pobieranego z sieci zasilającej. Analizę przeprowadzono przy użyciu wielkości względnych, co pozwala na proste ujecie zapisów analitycznych nadając im uniwersalny charakter. Podano warunki skuteczności i ograniczeń stosowania aktywnej pętli tłumiącej zjawiska rezonansowe w obwodzie filtru sieciowego. Rozważania teoretyczne zweryfikowano badaniami modelu laboratoryjnego.

EN

This paper describes properties of PWM current source converter from the ac power system with distorted line voltage point of view. The main part of this work is involved with problem of choosing LC filter parameters. The analysis of active damping control of resonance phenomena in LC filter and its influence on line current waveforms is given. A simplified time-domain model and analytic expressions have been presented to synthesis an output feedback loop. The analysis on per unit quantities have been made. The theoretical investigations are verified by experimental results captured from laboratory set-up.

13

Active Minimisation of Cumulated Load in the Drive Train by Dynamic Speed Flexible Operation

Sourkounis C.

Przegląd Elektrotechniczny

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2009

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R. 85, nr 10

267-271

EN

In electromechanical drive trains many processes cause stochastic loads with high amplitudes. This causes premature material fatigue, high thermal load on the asynchronous machine and load peaks in the mains. A novel control with rotational speed flexible operation (SC-control) was developed and tested based on the performance of shredding plants. The control is able to damp load peaks arising from the shredding process and thus to reduce the cumulative load in the drive train. A higher throughput was achieved while lowering the voltage fluctuations in the mains.

PL

W elektromechanicznym zespołach napędowych wiele procesów wiąże się z występowaniem obciążeń stochastycznych o wysokich amplitudach. Powoduje to przedwczesne zmęczenie materiału, wysokie obciążenia termiczne maszyny asynchronicznej i szczytowe obciążenie sieci. Opracowane nowe sterowanie, z elastycznym działaniem prędkości wirowania (SC-sterowanie), zostało przetestowane w oparciu o działanie urządzenia rozdrabniającego. To sterowanie jest w stanie tłumić szczytowe obciążenia wynikające z procesu rozdrabniania i w ten sposób zmniejszyć łączne obciążenie zespołu napędowego. Osiągnięto wyższą wydajność przy jednoczesnym zmniejszenia wahań napięcia w sieci.

14

Efficiency of Active Damping of Torsional Vibration in Shaft Made of Gradent Material with Piezoceramic Fraction

Przybyłowicz P. M.

Machine Dynamics Problems

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2008

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Vol. 32, No. 4

95-106

EN

The paper is concerned with the problem of active reduction of torsional vibratio shafts. The solution based on application of a functionally graded material is preset The material of the shaft consists of two components - a passive host material, which be a laminate with strong shear stiffness, and active fraction in form of a piezoelei ceramic. One component gradually passes into the other according to the g exponential distribution. Three cases varying by the level of internal friction in the pas fraction are analysed in terms of the efficiency of the active approach. For mode natural damping in the matrix, best distributions of the active phase are found.

15

Potential of manipulating the damping properties of parallel kinematic machine tools

Wabner M., Grzejszczyk S., Neugebauer R.

Journal of Machine Engineering

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2008

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Vol. 8, No. 1

63--76

EN

Parallel kinematics with a higher end-effector degree of freedom such as hexapods and pentapods consist of a large number of joints and slender struts. However, it is only possible to create comparably low levelsof bearing and strut bending stiffness atreasonable expense due to the limited construction space. That means that these structures are very susceptible to vibration. Even in the low-frequency range they have a large number of relevant eigenmodes that are only dampened slightly. Simultaneously, it is difficult to analyze vibrational properties due to coupled eigenmodes, which also makes it difficult to discover ways to remedy this situation. This article will take the example of a pentapod to analyze the dynamic properties of slightly dampened parallel kinematics by simulation to study potential means of manipulating it. This will include a description of the model formation of the mechanical system. The article will also address ways of reducing model size and using various simulation environments to boost analysis efficiency. Finally, both passive and active strategies will be studied and evaluated for boosting damping. Amongst others it could be shown that it is not necessary to damp every of the five kinematic chains to achieve effective improvement of the system damping behaviour.

16

From oil to magnetic fields: active and passive vibration control

Genta G., Festini A., Delepine X.

Acta Mechanica et Automatica

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2008

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Vol. 2, no. 2

11-20

EN

When a reduction of vibration amplitude usually designers resort to dampers based either on dry friction, internal material damping or fluid viscosity, each one of these mechanisms having its peculiar field of application. To improve performance while at the same time reducing costs and environmental load, electromagnetic damping devices are finding new applications, beyond the fields where they have a long history. Moreover, electromagnetic dampers can be easily controlled, obtain active or even ‘intelligent’ vibration control. Three examples from the internal combustion engines, automotive and gas turbine fields are discussed in some detail to show the potential advantages of this technology.

17

Resonant Behaviour of Geared System With Active Journal Bearings

Przybyłowicz P. M.

Machine Dynamics Problems

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2005

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Vol. 29, No. 1

93-104

EN

The paper is concerned with the problem of active control of resonant vibration of a geared transmission system with a rigid shaft supported on journal bearings. Toothed gears generate vibration due to variable meshing stiffness and other dynamic phenomena affecting the course and amplitude of contact forces between teeth. Moreover, geared systems exhibit resonance behaviour characterized by considerable variations of the meshing force that reaches more than a double of the static level. Such strongly oscillating forces cause vibrations of the entire gear assembly and deteriorate its operational features. In the paper, it is assumed that the gear shaft is supported on journal bearings instead of roll ones as in typical designs. Additionally, the bearings are active elements adjustable to current working conditions. The control system is based on the application of piezoelectric elements which are used to change the thickness of the oil gap with growing angular velocity of the rotor. The size of the oil gap greatly changes the dynamic properties of the bearings, including those related to damping capability. It is shown that the assumption of the simplest proportional control strategy, i.e. proportional to the rotation speed, yields an apparent drop in the amplitude of resonant vibration.

18

Stany przejściowe w układzie zasilania zagrażające funkcjonowaniu sieciowych pojazdów trakcyjnych z napędem energoelektronicznym

Karwowski K., Skibicki J.

Przegląd Elektrotechniczny

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2004

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R. 80, nr 10

1020-1024

PL

Sieciowe pojazdy trakcyjne są wyposażane w filtry wejściowe LC, tłumiące tętnienia prądu, przekształtniki impulsowe PWM, przetwarzające energię prądu stałego na trójfazową prądu przemiennego zasilającą silniki indukcyjne, oraz sterowniki komputerowe, realizujące algorytmy sterowania napędem. Jednym z zagrożeń w funkcjonowaniu tego typu pojazdów jest potencjalna możliwość pojawienia się oscylacji napięcia i prądu w układzie zasilania. Przedstawiono rezultaty komputerowej analizy systemu - podstacje trakcyjne, sieć trakcyjna i pojazdy.

EN

Rail vehicles are usually equipped in LC input filters for current ripple rejection, PWM converters for DC to three phase conversion, induction motors and computer controllers for drive control. One of the risks in this kind of vehicle operating is that voltage and current oscillation might appear in power supply system. This paper presents the results of the computer analysis of the system - traction substation, contact line system and vehicles.

19

Wpływ rozmieszczenia włókien piezoelektrycznych na aktywne tłumienie drgań płyt laminowanych

Pietrzakowski M.

Czasopismo Techniczne. Mechanika

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2004

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R. 101, z. 5-M

293--301

PL

Praca stanowi rozwinięcie analizy aktywnego tłumienia drgań płyt laminowanych. Do realizacji celu sterowania zastosowano warstwy wykonawcze z piezokompozytu typu IDEPFC i warstwy pomiarowe piezopolimeru PVDF. Analiza dotyczy drgań ustalonych i wpływu orientacji osi właściwości materiałowych warstw aktywnych na efektywność sterowania, a szczególnie - zdolność układu do redukcji wybranych postaci drgań własnych. Przedstawiono także wpływ tłumienia materiałowego na reakcję dynamiczną aktywnego laminatu.

EN

The paper develops the analysis for active structural vibration suppression of laminated plates. The control purposes are realized by the Interdigitated Electrode Piezoelectric Fiber Composites (IDEPFCs) used as actuator layers co-operating with the piezopolymer (PVDF) sensor layers. The dynamic analysis concerns the steady-state vibration and the influence of the material axes orientation of the active layers on the control effectiveness and the capability to suppress selected vibration modes. The effects of the material damping consideration on the active laminate behaviour are also exposed.

20

Damping of vibrations through torsion damper during starting power transmission system.

Skup Z.

Archive of Mechanical Engineering

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2004

|

Vol. LI, nr 2

165-180

EN

This paper presents a study of the damping of nonlinear vibrations in a two-mass model od mechanical system containing a torsion damper. The starting of a system by harmonic excitation is considered on the assumption of uniformly varying frequency and constant amplitude of the forced moment. Simultaneous structural friction phenomena (passive damping) and piezoelectric effect (active damping) have been considered as well. The problem is considered on the assumption of a uniform unit pressure distribution between the contacting surfaces of friction discs and plunger. The aim of the analysis is to asses the influence of angular acceleration, unitary pressure, external load and electric parameters on the resonance curves of the starting vibrations. The equations of motion of the tested system were solved by means of the Krylov-Bogolubov-Mitropolski method and digital simulation method.

PL

Praca dotyczy badania tłumienia drgań nieliniowych układu mechanicznego o dwóch stopniach swobody zawierającego tłumik drgań skrętnych. Rozważany jest rozruch układu przy wymuszeniu harmonicznym z jednostajnie zmienną częstością o stałej amplitudzie momentu wymuszającego. Uwzględniono tłumienie drgań wykorzystując zjawisko tarcia konstrukcyjnego (tłumienie pasywne) i efekt piezoelektryczny (tłumienie aktywne). Zagadnienie rozpatrywane jest przy założeniu równomiernego rozkładu nacisków jednostkowych występujących pomiędzy współpracującymi powierzchniami tarcz ciernych i bezwładnika. Zbadano wpływ przyspieszenia kątowego, nacisku jednostkowego, obciążenia zewnetrznego oraz współczynnika wzmocnienia na krzywe rezonansowe drgań rozruchowych. Równania ruchu badanego układu mechanicznego rozwiązano wykorzystując asymptotyczną metodę Kryłowa-Bogolubowa-Mitropolskiego i metodę symulacji cyfrowej.