Academic literature on the topic 'Parametric vibrations'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Parametric vibrations.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Parametric vibrations"
1
Гапонюк, Т. О., Р. В. Кірчук, and Л. Ю. Забродоцька. "USING HYDRAULIC PARAMETRIC VIBRATION EXCITER IN AGRICULTURAL ENGINEERING." СІЛЬСЬКОГОСПОДАРСЬКІ МАШИНИ, no. 48 (October 31, 2022): 7–14. http://dx.doi.org/10.36910/acm.vi48.778.
Full textAbstract:
Vibration technology is widely used in mechanical engineering, construction, road building and different sectors of the manufacturing. In agriculture, it is used for dosing feed, cleaning and sorting seeds, digging up root crops, planting potatoes, and transporting bulk materials. Vibrations make the mechanical system more stable in relation to external force disturbances and do not change the technological properties of materials during its movement along the working surfaces. Also, the material passing through the vibration zone is not damaged. A wide range of frequency and amplitude of vibrations provides the possibility of vibration regime varying, and the characteristics of the movement of agricultural plant material on the vibrating working bodies. The analysis of possibility of application of vibrating hydraulic drives as elements of transmission of movement to working bodies of agricultural machines is executed. A historical excursion was conducted and the first mentions of the use of hydraulic drives were pointed out. The estimation of technological processes in agricultural production where it is expedient and possible to use vibration and vibrating drives is made. At the present stage of development of agricultural engineering, using vibrating hydraulic drive is accorded to the basic trends of agriculture machinery development. The stand for conduction of studies of amplitude-frequency characteristics of the vibrating drive with regulated perturbations is offered. A mathematical model is presented, which generally describes the course of the vibration process and estimates the stiffness of the mechanical system. The hydraulic parametric vibration exciter is recommended to use for studying and determination the conditions for the occurrence of parametric vibrations in working body of agricultural machines. Also, using a hydraulic drive makes it possible to simplify the kinematics, reduce metal consumption, increase accuracy, reliability and level of automation of working bodies of agricultural machines.
2
Reiterer, Michael, and Joachim Muik. "Application of Parametric Forced Tuned Solid Ball Dampers for Vibration Control of Engineering Structures." Applied Sciences 13, no. 12 (2023): 7283. http://dx.doi.org/10.3390/app13127283.
Full textAbstract:
In this paper, parametric forced tuned solid ball dampers (TSBD) are considered for vibration control of engineering structures in an untypical way. The special feature of the presented investigation is to evaluate the potential application of parametric forcing of the rolling cylindrical or spherical body in the runway for reducing the vertical vibrations of a vibration-prone main system. Typically, tuned solid ball dampers are applied to structures that are prone to horizontal vibrations only. The coupled nonlinear differential equations of motion are derived and the phenomenon of parametric resonance of the rolling body in the runway is analyzed. A criterion for avoiding parametric resonance is given to achieve the optimal damping effect of the TSBD. In the second part of the article, a method for the targeted use of parametric resonance to reduce the vertical vibrations of engineering structures is presented and verified, considering a biaxially harmonic excited pedestrian bridge. It is shown that, with a suitable choice of damper parameters, a stable vibration of the rolling body in the runway is formed over the course of the vibration despite the occurrence of parametric resonance and that the maximum vertical vibration amplitudes of the main system can be reduced up to 93%. Hence, the here presented untypical application of parametric forced TSBD for reducing the vertical forced vibrations of vibration-prone main systems could be successfully demonstrated.
3
Dohnal, F. "Experimental studies on damping by parametric excitation using electromagnets." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 226, no. 8 (2012): 2015–27. http://dx.doi.org/10.1177/0954406212439515.
Full textAbstract:
Transient vibrations in mechanical systems are a common problem in engineering. Several theoretical studies have shown analytically and numerically that a vibrating system can be stabilised or its vibrations can be reduced when excited close to a specific parametric combination resonance frequency. At this operation, the transient vibrations are effectively damped by parametric excitation. The basic step in exploiting this method is its experimental implementation in mechanical systems. In this review, recent experiments are discussed for a simple chain mass system, a continuous cantilever and a flexible rotor system. The parametric excitation is realised by electromagnetic variable-stiffness actuators driven by a periodic open-loop control. It is demonstrated experimentally that a parametrically excited structure can exhibit enhanced damping properties. A certain level of the excitation amplitude has to be exceeded to achieve the damping effect in which the existing damping in the system is artificially amplified. Upon exceeding this value, the additional artificial damping provided to the system is significant and most effective for vibration suppression of the lower vibration modes.
4
Andrew, Zivai Borerwe. "Drill string vibrational analysis and parametric optimization for a portable water well rig development." i-manager's Journal on Mechanical Engineering 14, no. 2 (2024): 8. http://dx.doi.org/10.26634/jme.14.2.21011.
Full textAbstract:
The vibration of a drill string is a key topic of study in drilling and mining engineering. Excessive Drill String (DS) vibrations can lead to early failure of bits due to fatigue, Drill Pipe (DP) fractures, bearing damage, and a decrease in the Rate of Penetration (ROP). This occurs when the drill string rotates at its natural frequency, which is known as resonance. A modal and harmonic vibrational analysis of a drill string up to 60-65 meters long was conducted in a vertical water well through parametric studies. This project investigates the vibration of a drill string under various parameters, including drill string lengths, Weight on Bit (WOB), and drill string rotational speeds. The Rotational Speed (RS) in the drill string induces lateral vibrations and stick-slip in torsional vibrations. Finite element modeling of the drill string was performed using ANSYS Workbench (Mechanical). Modal and harmonic frequencies were determined to obtain the optimal drill string length and rotational speeds, using Campbell diagrams and varying weights on bits. Different weights on the bit were assumed to simulate the drilling environment. One of the modern methods used to simulate dynamic behavior in drilling operations is random vibrational analysis. A random vibrational analysis of the drill string was performed in a vertical water well using ANSYS Workbench 2020. This analysis aimed to identify the frequency response of the drill string, with the probability of deformation for each sigma under random vibration being evaluated. The analysis indicated a higher probability approximately 99.7% of failure along the axis of the supplied PSD acceleration. The response power spectral density (RPSD) was analyzed in the x, y, and z directions, focusing on any point in the bottom hole assembly, primarily the bit. The response PSD results indicated that as the Drill Pipe (DP) increased, resonance spikes rose across all axes, leading to lateral and longitudinal vibrations in the drill string. These findings highlight lateral movement as a primary cause of vibration, offering insights for optimizing drilling parameters.
5
Gao, Nan, Chanannipat Meesap, Shiyu Wang, and Dongsheng Zhang. "Parametric vibrations and instabilities of an elliptical gear pair." Journal of Vibration and Control 26, no. 19-20 (2020): 1721–34. http://dx.doi.org/10.1177/1077546320902543.
Full textAbstract:
Parametric vibrations and instabilities can be induced in an elliptical gear pair. This study examined the effects of basic parameters on vibration instability. Geometric parameters and time-variant mesh stiffness are calculated. A torsional dynamic model is established by introducing the lumped parameter assumption. Based on the model, the parametric vibrations caused by the excitations of eccentricity and time-variant mesh stiffness are investigated, and the additive and difference combination resonances are identified. Comparison between the elliptical and circular gears implies that the vibration amplitude at mesh frequency of the elliptical gears is lower than that of the regular circular gears. The vibrations caused by load torque are also examined. The results show that the vibrations with different frequencies are coupled with each other. The inherent reason behind the coupling is the interaction between the eccentricity, time-variant stiffness, and load.
6
Chen, Xiaojuan, Mengyang Han, Xiaolong Yang, and Bo Wang. "Stability Analysis of Parametric Vibration in Overhead Conductors Under Time-Varying Tension." Symmetry 17, no. 3 (2025): 464. https://doi.org/10.3390/sym17030464.
Full textAbstract:
This paper investigates the impact of dynamic tension induced by adjacent span vibrations on the vibrational characteristics of overhead conductors. A simplified model is established, considering the overhead conductor with a symmetric structure as a simply supported flexible long wire subjected to axial time-varying tension at one end. The transverse motion partial differential equation of the overhead conductor under time-varying tension is formulated and discretized into a parametric vibration equation with time-varying coefficients using the Galerkin method. Based on Floquet theory, the study systematically analyzes the influence of time-varying tension on system stability, delineates the boundaries of parametric resonance instability regions, and conducts time-history analysis of vibrational responses within these regions. The research demonstrates that when the frequency of the time-varying tension approaches the line’s natural frequency or its double, the system is prone to instability. While the damping coefficient can enhance system stability, it has limited effectiveness in suppressing the primary instability region. The study found that the vibrational responses of parametric vibrations exhibit nearly symmetric distributions within the instability regions and along the critical boundaries. Adjusting the frequency differences between adjacent spans effectively mitigates the parametric resonance issues in overhead conductors, providing valuable insights for engineering design.
7
Frumen, A. "Imitative simulation of parametric beam vibrations." Transactions of the Krylov State Research Centre S-I, no. 2 (2020): 110–12. http://dx.doi.org/10.24937/2542-2324-2020-2-s-i-110-112.
Full textAbstract:
This paper discusses two approaches to the investigation of parametric vibrations for beam structures: the approximate approach also known as VKB method (phase integrals) and the iterative algorithm basically simulating the process of vibration. The study compares the results yielded by these two approaches for a compressed freely supported beam and a ring under external compression load. The problem was solved through graphic programming in PVISSIM environment.
8
Zettel, Sebastian, René Winter, Marco Norambuena, and Marc Böswald. "Numerical investigation of power flow input into a fuselage due to jet engine induced wing vibrations." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, no. 5 (2023): 2288–97. http://dx.doi.org/10.3397/in_2022_0327.
Full textAbstract:
The wings of passenger aircrafts are constantly vibrating due to various loads. There are transient low-frequency vibrations caused by gust loads. But there are also higher-frequency vibrations caused by the vibration load of the jet engines. The higher-frequency stationary vibrations of the wing are partially introduced as a power flow into the fuselage and radiated there as sound, which is then perceived as noise. In this work, which is part of the EU CleanSky2 framework, this chain of effects is being investigated in more detail aiming for the quantification of the vibrational power flow input into the fuselage by utilizing structural intensity. In this paper, numerical investigations are carried out on FEM models of an Airbus A320 wing generated with a parametric model generator. First, the structural components mainly responsible for the power transmission are identified, and second, the magnitude of the power input into the fuselage is determined in dependence of the pylon position along the wing. The engine vibrations are approximated by a custom-developed model. In the further course of the project, these numerical results will be validated by a test campaign. For this purpose, a real wing of an A320 is available as a test structure.
9
Pešek, Ludek, Petr Šulc, and Ladislav Půst. "Numerical Study of Forced Vibration Suppression by Parametric Anti-Resonance." Archives of Acoustics 41, no. 3 (2016): 527–33. http://dx.doi.org/10.1515/aoa-2016-0051.
Full textAbstract:
Abstract 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.
10
Beltran-Carbajal, Francisco, Hugo Francisco Abundis-Fong, Luis Gerardo Trujillo-Franco, Hugo Yañez-Badillo, Antonio Favela-Contreras, and Eduardo Campos-Mercado. "Online Frequency Estimation on a Building-like Structure Using a Nonlinear Flexible Dynamic Vibration Absorber." Mathematics 10, no. 5 (2022): 708. http://dx.doi.org/10.3390/math10050708.
Full textAbstract:
The online frequency estimation of forced harmonic vibrations on a building-like structure, using a nonlinear flexible vibration absorber in a cantilever beam configuration, is addressed in this article. Algebraic formulae to compute online the harmonic excitation frequency on the nonlinear vibrating mechanical system using solely available measurement signals of position, velocity, or acceleration are presented. Fast algebraic frequency estimation can, thus, be implemented to tune online a semi-active dynamic vibration absorber to obtain a high attenuation level of undesirable vibrations affecting the main mechanical system. A semi-active vibration absorber can be tuned for application where variations of the excitation frequency can be expected. Adaptive vibration absorption for forced harmonic vibration suppression for operational scenarios with variable excitation frequency can be then performed. Analytical, numerical, and experimental results to demonstrate the effectiveness and efficiency of the operating frequency estimation, as well as the acceptable attenuation level achieved by the tunable flexible vibration absorber, are presented. The algebraic parametric estimation approach can be extended to add capabilities of variable frequency vibration suppression for several configurations of dynamic vibration absorbers.
Dissertations / Theses on the topic "Parametric vibrations"
1
Manzione, Piergiuseppe. "Nonlinear transverse vibrations of centrally clamped rotating circular disks." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/31524.
Full textAbstract:
A study is presented of the instability mechanisms of a damped axisymmetric circular disk of uniform thickness rotating about its axis with constant angular velocity and subjected to various transverse space-fixed loading systems.
The natural frequencies of spinning floppy disks are obtained for various nodal diameters and nodal circles with a numerical and an approximate method.
Exploiting the fact that in most physical applications the thickness of the disk is small compared with its outer radius, we use their ratio to define a small parameter.
Because the nonlinearities appearing in the governing partial-differential equations are cubic, we use the Galerkin procedure to reduce the problem into a finite number of coupled weakly nonlinear second-order equations.
The coefficients of the nonlinear terms in the reduced equations are calculated for a wide range of the lowest modes and for different rotational speeds. We have studied the primary resonance of a pair of orthogonal modes under a space-fixed constant loading, the principal parametric resonance of a pair of orthogonal modes when the disk is subject to a massive loading system, and the combination parametric resonance of two pairs of orthogonal modes when the excitation is a linear spring.
Considering the case of a spring moving periodically along the radius of the disk, we show how its frequency can be coupled to the rotational speed of the disk and lead to a principal parametric resonance. In each of these cases, we have used the method of multiple scales to determine the equations governing the modulation of the amplitudes and phases of the interacting modes.
The equilibrium solutions of the modulation equations are determined and their stability is studied.<br>Master of Science
2
Sternchuss, Arnaud Balmès Etienne. "Multi-level parametric reduced models of rotating bladed disk assemblies." S. l. : Ecole centrale de Paris, 2009. http://theses.abes.fr/2009ECAP0001.
Full text
3
Megnounif, Abdellatif. "Parametric study on human response to vibrations of box girder bridges." Thesis, University of Ottawa (Canada), 1988. http://hdl.handle.net/10393/5339.
Full text
4
Oueini, Shafic Sami. "Techniques for Controlling Structural Vibrations." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/27176.
Full textAbstract:
We tackle the problem of suppressing high-amplitude vibrations of cantilever beams when subjected to either primary external or principal parametric resonances. Guided by results of previous investigations into the nonlinear dynamics of single- and multi-degree-of-freedom structures, we design mechatronic systems of sensors, actuators, and electronic devices and implement nonlinear active feedback control.
In the case of external excitation, we devise two vibration absorbers based on either quadratic or cubic feedback. We conduct theoretical analyses and demonstrate that when a two-to-one (one-to-one) internal resonance condition is imposed between the plant and the quadratic (cubic) absorber, there exists a saturation phenomenon. When the plant is forced near its resonant frequency and the forcing amplitude exceeds a certain small threshold, the nonlinear coupling creates an energy-transfer mechanism that limits (saturates) the response of the plant.
Our theoretical studies reveal that the cubic absorber creates regimes of high-amplitude quasiperiodic and chaotic responses, thereby limiting its utility. However, we show that superior results can be achieved when the natural frequency of the quadratic absorber is set equal to one-half the excitation frequency. Consequently, we apply the quadratic technique through a variety of linear and nonlinear actuators, sensors, and electronic devices.
We design and build second-order analog circuits that emulate the quadratic absorber. Using a DC motor, piezoelectric ceramics, and Terfenol-D struts as actuators and potentiometers, strain gages, and accelerometers as sensors, we demonstrate successful single- and multi-mode vibration control.
In order to realize a more versatile implementation of the control strategy, we resort to a digital signal processing (DSP) board. We compose a code in C and design a digital absorber by developing algorithms that, in addition to replacing the analog circuit, automatically detect the amplitude and frequency of oscillation of the plant and fine-tune the absorber parameters.
We take advantage of the digital realization, implement a linear absorber, and compare the performance of the quadratic absorber with that of its linear counterpart.
In the case of parametric excitation, we investigate two techniques. First, we explore application of the quadratic absorber. We prove theoretically and demonstrate experimentally that this control scheme is not reliable. Then, we propose an alternate approach. We devise a control law based on cubic velocity feedback. We conduct theoretical and experimental investigations and show that the latter strategy leads to effective vibration suppression and bifurcation control.<br>Ph. D.
5
Winnard, Thomas Johan. "Theoretical Parametric Study of Through-Wall Acoustic Energy Transfer Systems." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/103387.
Full textAbstract:
Technological advances require novel solutions for contactless energy transfer. Many engineering applications require unique approaches to power electrical components without using physical wires. In the past decade, awareness of the need to wirelessly power electrical components spawned many forays into the field of wireless power transfer (WPT). WPT techniques include capacitive energy transfer, electromagnetic inductive power transfer, electromagnetic radiative power transfer, electrostatic induction, and acoustic energy transfer. Acoustic energy transfer (AET) has many advantages over other methods. These advantages include lower operating frequency, shorter wavelengths enabling the use of smaller sized receiver and transmitter, extended transmitter-to-receiver distance therefore more manageable design constraints, achieving lower attenuation, higher penetration depth, and no electromagnetic losses. Most AET systems operate in the ultrasonic frequency range and are more commonly referred to as ultrasonic acoustic energy transfer (UAET) systems.
Through-wall UAET systems are constructed of a transmitter bonded to a transmission elastic layer, which in turn is bonded to a receiver. The transmitter and receiver layers are constructed of a piezoelectric material. Piezoelectric materials behave according to the piezoelectric effect, which is when a material generates an electric charge in response to mechanical strain. The transmitter utilizes the reverse of the piezoelectric effect. A sinusoidal input voltage is applied to the transmitter, inducing vibrations in the transmitter. The vibration-induced acoustic waves emanating from the transmitter travel through the initial bonding layer, the transmission layer, and the final bonding layer to the receiver. In turn, the acoustic waves cause the receiver to deform and undergo strain. This induces a flow of charge in the receiver, which is an electric current. The receiver feeds current to a resistive load. In this manner, energy is acoustically transferred between two transducers without wires. The performance of UAET systems can be evaluated based on power transfer efficiency, voltage magnification, and input admittance.
UAET systems require extensive modeling before experimental assembly can be attempted. The analytical models of UAET are either based on the mechanics of the constitutive relations of piezoelectricity and solid mechanics or using equivalent circuit methods. The equivalent circuit method approximates the physics of the UAET system with electrical assumptions. The mechanics-based method is the most comprehensive description of the physics of all the intermediate layers in a UAET system.
The mechanics-based method has been based on the assumption that the UAET system is operated in the thickness mode of vibration, i.e., piston-like vibration mode where the transmitter and receiver disks vibrate only in the thickness direction. This poses an issue for disks with aspect ratios between 0.1 and 20 because the piezoelectric transducers vibrate in both the radial and thickness modes.
In addition to this assumption, most of the works on UAET models only have accounted for the piezoelectric and transmission layers. The effects of the bonding layers were not considered. Bonding the piezoelectric layers to the transmission layer introduces epoxy material with mechanical properties that are not accounted for. The epoxy layers are extra barriers to the transmission that introduce attenuation and alter the vibrational and acoustical behaviors of the UAET system.
Investigations into UAET commonly focus on metal through-wall applications. Alternate transmission layer materials are not investigated and the impact of varying mechanical properties on the performance of a through-wall UAET system has not been comprehensively studied. Even with the metal transmission layers, the impact of the metal thickness has not been extensively investigated thoroughly.
This work addresses the issues of the thickness-mode assumption in UAET modeling, the effects of epoxy layers, the impacts of the metal layer geometry, and the performance of UAET systems with alternate transmission layer materials. Particularly, (1) we showed that the thickness-mode assumption, that has been used in the UAET modeling leads to inaccurate results. (2) We modified the available acoustic electro- elastic theoretical modeling to include the effects of radial modes as well as the epoxy bonding layers. (3) We showed that the geometry of the elastic/metal layer requires optimization for peak system efficiency. (4) The results show that using alternate transmission layer materials impacts the performance of UAET systems. The results of this work were investigated using an improved 5-layer analytical model and finite element modeling in COMSOL Multiphysics.<br>Master of Science<br>Wireless power transfer (WPT) is an innovative solution to the problem of powering sophisticated technological applications. Such instances include the powering of implanted medical devices, recharging inaccessible sensor networks, and wireless powering of components in sealed containers. Acoustic energy transfer (AET) is a feasible WPT method that addresses these needs. AET is based on the propagation of acoustic waves to a piezoelectric receiver which converts the vibrations caused by incident acoustic waves into electrical energy. Most AET systems operate in the ultrasonic frequency range, and so AET can also be referred to as ultrasonic acoustic energy transfer (UAET). Through-wall UAET systems are constructed from a transmitter that is bonded to a transmission elastic layer. The transmission layer is bonded to a receiver. The transmitter and receiver are made of a piezoelectric material.
This thesis addresses the modeling process of through-wall UAET systems. In previous works, the fundamental assumption has been that such systems vibrate purely in the thickness mode. Additionally, other investigations did not comprehensively analyze the effects of the bonding layers, ascertain the performance of non-metal transmission layers, or provide practical insight on the effect of the resistive loading on such systems. This work addresses all these issues with a mathematical framework and finite element modeling results.
6
Kurpa, Lidiya, Olga Mazur, and Igor Tsukanov. "Application of R-Functions Theory to Study Parametric Vibrations and Dynamical Stability of Laminated Plates." Thesis, Точка, 2013. http://repository.kpi.kharkov.ua/handle/KhPI-Press/37087.
Full textAbstract:
The problem of nonlinear parametric vibrations and stability analysis of the symmetric laminated
plates is considered. The proposed method is based on multimode approximation of displacements
and solving series auxiliary linear tasks. The main feature of the work is the application of the R-functions
theory, which allows investigating parametric vibrations of plates with complex shape and
different boundary conditions.
7
Grenat, Clément. "Nonlinear Normal Modes and multi-parametric continuation of bifurcations : Application to vibration absorbers and architectured MEMS sensors for mass detection." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI078/document.
Full textAbstract:
Un des buts de cette thèse est d’approfondir la compréhension de la dynamique non-linéaire, notamment celle des MEMS, en proposant de nouvelles méthodes d’analyse paramétrique et de calcul de modes normaux non-linéaires. Dans une première partie, les méthodes de détection, de localisation et de suivi de points de bifurcation selon un unique paramètre sont rappelées. Ensuite, une nouvelle méthode d’analyse multiparamétrique basée sur la continuation récursive d’extremums est présentée. Cette méthode est ensuite appliquée à un absorbeur de vibration non-linéaire afin de repousser l’apparition de solutions isolées. Deuxièmement, une méthode de calcul de modes normaux non-linéaires est présentée. Une condition de phase optimale et une régularisation de l’équation de mouvement sont proposées afin d’obtenir une méthode de continuation plus robuste au niveau des interactions modales. Ensuite, un problème quadratique aux valeurs propres modifié pour le calcul de stabilité et de points de bifurcation est présenté. Finalement, le calcul de modes normaux non-linéaires a été étendu aux systèmes non-conservatifs permettant la continuation des résonances d’énergie en déplacement et des résonances de phase. Troisièmement, la dynamique non-linéaire de réseaux de MEMS basé sur plusieurs micro-poutres résonantes est analysée à l’aide des méthodes proposées. Tout d'abord, un phénomène de synchronisation de points de bifurcations dû au couplage électrostatique dans les réseaux de MEMS est expliqué. Puis, la dynamique non-linéaire d'un réseau dissymétrisé par l'ajout d'une petite masse sur une micro-poutre est analysée. Enfin, des mécanismes de détection de masse exploitant ces phénomènes non-linéaires sont présentés<br>One of the goals of this thesis is to enhance the comprehension of nonlinear dynamics, especially MEMS nonlinear dynamics, by proposing new methods for parametric analysis and for nonlinear normal modes computation. In a first part, methods for the detection, the localization and the tracking of bifurcation points with respect to a single parameter are recalled. Then, a new method for parametric analysis, based on recursive continuation of extremum, is presented. This method is then applied to a Nonlinear Tuned Vibration Absorber in order to push isolated solutions at higher amplitude of forcing. Secondly, a method is presented for the computation of nonlinear normal modes. An optimal phase condition and a relaxation of the equation of motion are proposed to obtain a continuation method able to handle modal interactions. Then, a quadratic eigenvalue problem is shifted to compute the stability and bifurcation points. Finally, nonlinear normal modes are extended to non-conservatives systems permitting the continuation of phase and energy resonances. Thirdly, the nonlinear dynamics of MEMS array, based on multiple resonant micro-beams, is analyzed with the help of the proposed methods. A frequency synchronization of bifurcation points due to the electrostatic coupling is discovered. Then, the nonlinear dynamics of a MEMS array after symmetry breaking event induced by the addition of a small mass onto one of the beam of the array is analyzed. Finally, mass detection mechanisms exploiting the discovered phenomena are presented
8
Schirén, Whokko, and Trixie Swahn. "Vibrations in residential timber floors : A comparison between the current and the revised Eurocode 5." Thesis, Linnéuniversitetet, Institutionen för byggteknik (BY), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-89293.
Full textAbstract:
The European standard Eurocode 5, a design method for timber structures,is currently under revision. In this study the draft for a reviseddesign method for vibrations in timber floors was compared to the currentmethod. The hypothesis of the thesis was that the revised designmethod might force some changes to the present construction practiceand that these changes may carry with them increased costs for the industry.Six common floor structures used in Sweden today were identifiedand for these floors design calculations were made according to the currentand the revised design method. It was checked whether the floorspassed the criteria in the two design methods and a comparison was madefor the only criterion which could be compared between the methods, thepoint load deflection. Floor structures could pass or fail the current designmethod based on two criteria, the point load deflection and the unitimpulse velocity response. All floors passed the current design methodexcept one which had a fundamental frequency below 8 Hz, because ofthe low frequency the current design method was not applicable to thefloor structure. In the revised design method the final result is a responsefactor and based on the response factor floors are given floor performancelevels. The seven step scale for the floor performance level go from I toVII where I is excellent and VII is unacceptable. All floor structures excepttwo achieved an acceptable floor performance level according to therevised design method. The two floors which failed were floors commonlyused in single family houses, they failed for a span length commonly usedtoday. A limited parametric study was performed where it was found thatthe modal mass used had a larger impact on the floor performance levelthan the mass per square meter included. For floors with a fundamentalfrequency above 8 Hz, including a higher mass per square meter resultedin a lower, i.e. better, response factor in all cases except one. For floorswith a fundamental frequency between 4.5 and 8 Hz, a higher mass resultedin a higher, i.e. worse, response factor. The study found that notall floor structures used in Sweden today are acceptable according to therevised design method therefore changes may have to be implemented andthese changes could result in an increased cost.
9
Abboud, Eddy. "Simulation, mastering, and reduction of vibrations and noises in electric car gearbox transmission systems." Thesis, Paris, HESAM, 2022. http://www.theses.fr/2022HESAE026.
Full textAbstract:
Les architectures actuelles des motorisations hybrides ou électriques des véhicules automobiles incluent des transmissions par engrenages en sortie du moteur électrique, pour adapter la vitesse de rotation à celle des roues du véhicule. Ces engrenages sont la source de vibrations qui se propagent par voie solidienne jusqu'au carter du système, qui se retrouve être la sources acoustique du bruit rayonné. Ces bruits affectent le confort de l'utilisateur, notamment car ils ne sont pas masqués par le bruit du moteur électrique, très différent de celui d'un moteur thermique classique. La maîtrise de ces bruits est ainsi un enjeu majeur pour les constructeurs automobile actuels. Les sources de vibration dans les transmissions de puissance par engrenages sont nombreuses. On peut citer par exemple l'acyclisme du couple de sortie du moteur qui entraîne des fluctuations de la vitesse de rotation ou encore des phénomènes de variation périodique de la raideur d'engrènement sous couple, qui produisent une excitation vibratoire dite paramétrique, qui produit un bruit caractéristique de sirènement (whining noise en anglais). Dans ce contexte, plusieurs industriels se penchent actuellement sur la modélisation des vibrations dans les chaînes de transmission par engrenages, dans le but de prédire l'apparition des différents bruits et éventuellement d'ajuster la conception du système en conséquence. Le but de cette thèse est de mettre en place des modèles numériques afin de représenter le comportement vibratoire des systèmes d'engrenage. Dans ce contexte, plusieurs points ont été abordés: une étude paramétrique réalisée sur l'équation différentielle de l'interaction entre les engrenages permettant d'analyser et de prédire leur comportement dynamique. En parallèle, une méthode de calcul des vibrations dues à l'engrennement en utilisant la méthodes d'équilibrage des harmoniques (HBM) est proporséee. Enfin, une méthode de calcul d'un modèle réduit d'une boi te de transmission sous excitation de l'engrennement est présentée<br>The current architectures of hybrid or electric motorizations of motor vehicles include transmissions by gears at the electric motor's output to adapt the speed of rotation to that of the vehicle wheels. These gears are the source of vibrations that propagate through the solid state to the system housing, the acoustic source of radiated noise. These noises affect the user's comfort, mainly because they are not masked by the noise of the electric motor, which is very different from that of a conventional combustion engine. Therefore, controlling this noise is a significant challenge for today's car manufacturers. There are many sources of vibration in geared power transmissions. For example, the engine's output torque's acyclic nature leads to rotational speed fluctuations, and periodic variations in the meshing stiffness under torque produce a so-called parametric vibration excitation, which produces a characteristic whining noise. In this context, several manufacturers are currently studying the modeling of vibrations in gear transmission systems, intending to predict the appearance of the various noises and possibly adjust the system's design accordingly. This thesis aims to set up numerical models to represent the vibratory behavior of gear systems from the understanding of the interaction between mating gears, to the dynamic presentation of a complete gearbox. Several points have been addressed in this context: a parametric study is performed on the differential equation of the interaction between gears to analyze and predict their dynamic behavior. In parallel, a method for calculating the vibrations due to the meshing process using the harmonic balancing method (HBM) is proposed. Finally, a method for calculating a reduced gearbox model under gear excitation is presented
10
Airimitoaie, Tudor-Bogdan. "Commande robuste et calibrage des systèmes de contrôle actif de vibrations." Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENT015/document.
Full textAbstract:
Dans cette thèse, nous présentons des solutions pour la conception des systèmes de contrôle actif de vibrations. Dans la première partie, des méthodes de contrôle par action anticipatrice (feedforward) sont développées. Celles-ci sont dédiées à la suppression des perturbations bande large en utilisant une image de la perturbation mesurée par un deuxième capteur, en amont de la variable de performance à minimiser. Les algorithmes présentés dans cette mémoire sont conçus pour réaliser de bonnes performances et maintenir la stabilité du système en présence du couplage positif interne qui apparaît entre le signal de commande et l'image de la perturbation. Les principales contributions de cette partie sont l'assouplissement de la condition de « Stricte Positivité Réelle » (SPR) par l'utilisation des algorithmes d'adaptation « Intégrale + Proportionnelle » et le développement de compensateurs à action anticipatrice (feedforward) sur la base de la paramétrisation Youla-Kučera. La deuxième partie de la thèse concerne le rejet des perturbations bande étroite par contre-réaction adaptative (feedback). Une méthode d'adaptation indirecte est proposée pour le rejet de plusieurs perturbations bande étroite en utilisant des filtres Stop-bande et la paramétrisation Youla-Kučera. Cette méthode utilise des Filtres Adaptatifs à Encoche en cascade pour estimer les fréquences de perturbations sinusoïdales puis des Filtres Stop-bande pour introduire des atténuations aux fréquences estimées. Les algorithmes sont vérifiés et validés sur un dispositif expérimental disponible au sein du département Automatique du laboratoire GIPSA-Lab de Grenoble<br>In this thesis, solutions for the design of robust Active Vibration Control (AVC) systems are presented. The thesis report is composed of two parts. In the first one, feedforward adaptive methods are developed. They are dedicated to the suppression of large band disturbances and use a measurement, correlated with the disturbance, obtained upstream from the performance variable by the use of a second transducer. The algorithms presented in this thesis are designed to achieve good performances and to maintain system stability in the presence of the internal feedback coupling which appears between the control signal and the image of the disturbance. The main contributions in this part are the relaxation of the Strictly Positive Real (SPR) condition appearing in the stability analysis of the algorithms by use of “Integral + Proportional” adaptation algorithms and the development of feedforward compensators for noise or vibration reduction based on the Youla-Kučera parameterization. The second part of this thesis is concerned with the negative feedback rejection of narrow band disturbances. An indirect adaptation method for the rejection of multiple narrow band disturbances using Band-Stop Filters (BSF) and the Youla-Kučera parameterization is presented. This method uses cascaded Adaptive Notch Filters (ANF) to estimate the frequencies of the disturbances' sinusoids and then, Band-stop Filters are used to shape the output sensitivity function independently, reducing the effect of each narrow band signal in the disturbance. The algorithms are verified and validated on an experimental setup available at the Control Systems Department of GIPSA-Lab, Grenoble, France
Books on the topic "Parametric vibrations"
1
Cartmell, Matthew. Introduction to linear, parametric, and nonlinear vibrations. Chapman and Hall, 1990.
Find full text
2
de Sá Caetano, Elsa. Cable Vibrations in Cable-Stayed Bridges. International Association for Bridge and Structural Engineering (IABSE), 2007. http://dx.doi.org/10.2749/sed009.
Full textAbstract:
<p>The fifty years of experience of construction of cable-stayed bridges since their establishment as a new category among the classical types have brought an immense progress, ranging from design and conception to materials, analysis, construction, observation and retrofitting. The growing construction of cable-stayed bridges has also triggered researchers’ and designers’ attention to the problem of cable vibrations. Intensive research has been developed all over the world during the last two decades as a consequence of the numerous cases of cable vibrations exhibited by all types of cable-stayed bridges.<p>Despite the increased knowledge of the various vibration phenomena, most of the outcomes and research results have been published in journals and conference proceedings and scarce information is currently provided by the existing recommendations and codes. <p>The present book provides a comprehensive survey on the governing phenomena of cable vibration, both associated with direct action of wind and rain: buffeting, vortex-shedding, wake effects, rain-wind vibration; and resulting from the indirect excitation through anchorage oscillation: external and parametric excitation. Methodologies for assessment of the effects of those phenomena are presented and illustrated by practical examples. Control of cable vibrations is then discussed and state-of-art results on the design of passive control devices are presented. <p>The book is complemented with a series of case reports reflecting the practical approach shared by experienced designers and consultants: Yves Bournand (VSL International), Chris Geurts (TNO), Carl Hansvold (Johs. Holt), Allan Larsen (Cowi) and Randall Poston (WDP & Associates).
3
Sneyd, A. D. Parametric resonance in systems of Mathieu equations. University of Waikato, Mathematics and Statistics, 1991.
Find full text
4
Kanevskiĭ, I. N. Kolebatelʹnye sistemy s sosredotochennymi parametrami. Dalʹnauka, 2004.
Find full text
5
Chun, R. C. Parametric study of pipe whip analysis. Division of Engineering, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1987.
Find full text
6
Redʹko, S. F. Identifikat͡s︡ii͡a︡ mekhanicheskikh sistem: Opredelenie dinamicheskikh kharakteristik i parametrov. Nauk. dumka, 1985.
Find full text
7
Center, Langley Research, ed. Parametric and experimental analysis using a power flow approach. National Aeronautics and Space Administration, Langley Research Center, 1990.
Find full text
8
United States. National Aeronautics and Space Administration., ed. Parametric and experimental analysis using a power flow approach. Florida Atlantic University, College of Engineering, Dept. of Ocean Engineering, Center for Acoustics and Vibrations, 1988.
Find full text
9
Xie, Jueren. Numerical investigation of eccentrically loaded tied high strength concrete columns. Dept. of Civil Engineering, University of Alberta, 1994.
Find full text
10
Palazzolo, Alan. Nonlinear, Parametric and Rotordynamic Vibrations. Wiley & Sons, Incorporated, John, 2022.
Find full textBook chapters on the topic "Parametric vibrations"
1
Moretti, Peter M. "Parametric Excitation." In Modern Vibrations Primer. CRC Press, 2024. http://dx.doi.org/10.1201/9781003574064-38.
Full text
2
Karnovsky, Igor A., and Evgeniy Lebed. "Active and Parametric Vibration Protection of Transient Vibrations." In Theory of Vibration Protection. Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-28020-2_13.
Full text
3
Vulfson, Iosif I. "Parametric Vibrations Excitation in Cyclic Mechanisms." In Advances in Mechanical Engineering. Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-53363-6_14.
Full text
4
Mikhasev, Gennadi I., and Petr E. Tovstik. "Localized Parametric Vibrations of Thin Shells." In Localized Dynamics of Thin-Walled Shells. Chapman and Hall/CRC, 2020. http://dx.doi.org/10.1201/9781315115467-5.
Full text
5
Wójcicki, Zbigniew. "Method of Stabilization of Resonant Parametric Vibrations." In Lecture Notes in Civil Engineering. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-86001-1_43.
Full text
6
Spelsberg-Korspeter, Gottfried. "Nonlinear Analysis of Systems Under Periodic Parametric Excitation." In Robust Structural Design against Self-Excited Vibrations. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36552-2_7.
Full text
7
Sergaliyev, Almaz, Julius Kaplunov, and Lelya Khajiyeva. "About Multi-parametric Analysis of Drill String Vibrations." In Mechanisms and Machine Science. Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-09918-7_33.
Full text
8
Liu, Airong, Hanwen Lu, Yong-Lin Pi, Youqing Huang, and Jing Li. "Out-of-Plane Parametric Resonance of Arches Under an In-Plane Central Harmonic Load." In Environmental Vibrations and Transportation Geodynamics. Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-4508-0_4.
Full text
9
Spelsberg-Korspeter, Gottfried. "Perturbation of a Linear Conservative System by Periodic Parametric Excitation." In Robust Structural Design against Self-Excited Vibrations. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-36552-2_2.
Full text
10
Tylikowski, Andrzej. "Active Damping of Parametric Vibrations of Mechanical Distributed Systems." In Solid Mechanics and Its Applications. Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-017-0371-0_40.
Full textConference papers on the topic "Parametric vibrations"
1
Guan, Peng, and Hans DeSmidt. "Ring Gear Vibration Suppression via Active Support Struts in a Planetary Gear Transmission." In Vertical Flight Society 74th Annual Forum & Technology Display. The Vertical Flight Society, 2018. http://dx.doi.org/10.4050/f-0074-2018-12865.
Full textAbstract:
This paper investigates an active vibration suppression method for planetary gear transmission (PGT) driveline system supported by discrete boundary struts. To effectively suppress the vibrations introduced by the parametric excitations, the proposed active vibration control method develops an output feedback controller via applying LQR theory to a reduced-order stationary ring gear model equipped with sensors collocated with boundary struts. Afterward, the output feedback controller is integrated to the PGT driveline system for actuator control to suppress the vibrations transmitted through boundary struts. Assume-modes method, Floquet theorem and harmonic balance method are used to obtain the steady-state response of the system. By including enough sensors and number of modes in the reduced-order ring gear model, the vibrations transmitted through boundary struts can be suppressed. Additionally, the vibrations in other PGT components are examined to ensure that the proposed control method does not introduce exaggerating behavior to those components.
2
Liu, Zhanhang, Lin Chen, Limin Sun, and Ashraf El Damatty. "A Reduced-order Modelling Approach for Vibration Mitigation Design of Long-span Suspension Bridges." In IABSE Congress, San José 2024: Beyond Structural Engineering in a Changing World. International Association for Bridge and Structural Engineering (IABSE), 2024. https://doi.org/10.2749/sanjose.2024.1161.
Full textAbstract:
<p>Long-span suspension bridges are susceptible to vibrations under the influence of wind loads, such as vortex-induced vibrations, which make the dynamic analysis of bridges incorporating mechanical damping devices crucial. This study introduces a reduced-order modelling approach, which ensures computational accuracy while significantly reducing computation time comparing with traditional full-bridge finite element model and is thus applicable to parametric design of dampers. A suspension bridge with a main span of 1650 meters was chosen for numerical validation, with damped outriggers employed as damping enhancement measurement. The dynamic characteristics of the bridge were computed respectively using both the finite element model and the proposed reduced-order model. The results indicate that the new approach demonstrates both efficiency and accuracy, proving its effectiveness in vibration mitigation design of suspension bridges.</p>
3
Ecker, Horst. "A Parametric Absorber for Friction-Induced Vibrations." In ASME 2003 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/detc2003/vib-48474.
Full textAbstract:
This contribution deals with the suppression of friction-induced vibrations of a mechanical system. A two-mass system is considered, with the main mass excited by a friction-generated self-excitation force and a smaller second mass attached to the main mass. The parameter of the connecting stiffness between the main mass and the absorber mass is a harmonic function of time and represents a parametric excitation. The purpose of the second mass is to act as a “parametric absorber” and to cancel vibrations. Critical values for the damping parameters of the conventional system are calculated, where the system operates on the stability limit. Analytical and numerical methods are employed to determine the stability of the parameter-excited system. A study for selected parameters shows within which limits friction-induced vibrations can be suppressed effectively by a parametric absorber.
4
Dohnal, F. "Dissipative Energy Flow in Systems at Parametric Anti-Resonance." In ASME 2012 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/detc2012-70864.
Full textAbstract:
Recent investigations have shown theoretically and experimentally that the transient vibrations of a lightly damped system can be suppressed or even stabilized by a time-periodic open-loop control of one of its system parameters. Introducing time-periodicity in system parameters may lead, in general, to a dangerous and well-known parametric resonance. In contrast to such a resonance, a properly tuned time-periodicity is capable to extract vibration energy from the system and to increase the effective damping of transient vibrations. At this specific operation the system is tuned at parametric anti-resonance. The beneficial interaction of damping and time-periodicity was first formulated by A. Tondl in 1998. His pioneering work deals with stabilizing self-excited vibrations. It was proven by F. Dohnal in 2005 that the vibrations of a general lightly damped system (not necessarily unstable) can be reduced by parametric anti-resonance, too. A physical interpretation of the parametric anti-resonance is related to the coupling of vibration modes of the underlying system with constant coefficients. This interpretation leads intuitively to the calculation of the energy flow of each vibration mode and leads to clear physical insight of how parametric anti-resonances work. This interpretation of mode coupling is developed further resulting in an approximate analytical expression for the effective damping of a system driven at parametric anti-resonance. This expression allows the statement of the maximum effective damping achievable by this method. The discussion of the energy flow of a linear, lightly damped system possessing a time-periodic stiffness coefficient its physical and modal displacements highlights the coupling of vibration modes of the underlying system with constant coefficients.
5
Popov, A. A., J. M. T. Thompson, and F. A. McRobie. "Parametrically Excited Vibrations and Auto-Parametric Resonance in Cylindrical Shells." In ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-1011.
Full textAbstract:
Abstract Vibrations of cylindrical shells parametrically excited by external axial forcing or by internal auto-parametric resonances are considered. A Rayleigh-Ritz discretization of the von Kármán-Donnell equations through symbolic computations leads to low dimensional models of shell vibration. After applying methods and ideas of modern dynamical systems theory, complete bifurcation diagrams are constructed and analyzed with an emphasis on modal interactions and their relevance to structural behaviour. In the case of free shell vibrations, the Hamiltonian and a transformation into action-angle coordinates followed by averaging provides readily a geometric description of the interaction between concertina and chequerboard modes. It was established that the interaction should be most pronounced when there are slightly less than 2 N square chequerboard panels circumferentially, where N is the ratio of shell radius to thickness. The two mode interaction leads to preferred vibration patterns with larger deflection inwards than outwards, and at internal resonance, significant energy transfer occurs between the modes. The regular and chaotic features of this interaction are studied analytically and numerically.
6
Tondl, Aleš, and Horst Ecker. "Cancelling of Self-Excited Vibrations by Means of Parametric Excitation." In ASME 1999 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/detc99/vib-8071.
Full textAbstract:
Abstract The possibility of cancelling self-excited vibrations of a mechanical system using parametric excitation is discussed. A two-mass system is considered, with the top mass excited by a flow-generated self-exciting force. The parameter of the connecting stiffness between the base mass and the foundation is a harmonic function of time and represents a parametric excitation. For such a system general conditions for full vibration cancelling are derived and presented. By means of numerical simulation the system is investigated for several sets of parameters. The theoretical results are found to be in very good agreement with the results obtained by simulation. Parameter variations show the extent of the parameter space where significant vibration cancelling can be achieved and illustrate possible applications.
7
Lai, J. S., and K. W. Wang. "Parametric Control of Structural Vibrations via Adaptable Stiffness Dynamic Absorbers." In ASME 1996 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/imece1996-0928.
Full textAbstract:
Abstract An energy-based algorithm is developed for dynamic absorbers with adaptable stiffness to suppress structural vibrations via real-time parametric control actions. A controller with multi-objective fuzzy logic is created to reduce the main structure energy while constraining the total system energy. An adaptive-passive supervisor is designed to provide guidelines for implementing the control law. It is proved that the system using this supervisor is globally stable in the sense that all signals involved are bounded. The performance of the controller is demonstrated on a beam example. It is shown that the structure energy level and vibration amplitude can be suppressed effectively.
8
Dosko, Sergey I., Sergey A. Sheptunov, Akelsey Yu Spasenov, and Kirill V. Kucherov. "Human Precardiac Zone Vibrations Analysis Using Parametric Spectral Methods." In 2020 International Conference on Quality Management, Transport and Information Security, Information Technologies (IT&QM&IS). IEEE, 2020. http://dx.doi.org/10.1109/itqmis51053.2020.9322983.
Full text
9
Tanaka, Tomotsugu, Koetsu Takano, Hiroyuki Fujiwara, and Osami Matsushita. "Reduction of Flow-Induced Vibration Using Parametric Excitation." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-33576.
Full textAbstract:
Vibration of structures, such as suspension bridges, skyscrapers and high rises, sometimes cause people to feel anxious. These vibrations are usually induced by the fluid flow, especially vortex shedding and they grow into self-excited vibrations, which are normally accompanied by the extremely large vibration amplitude. In order to solve these vibration problems, many researchers have reported the effectiveness of vibration control methods and most of the methods are very practical for the actual structure. These control methods usually consist of feedback control systems for the active control and some kinds of damper for the passive control. This paper deals with one control method, which is using the parametric excitation. The efficiencies of this method for the self-excited vibration have already been analytically examined by Tondl. However, it is not confirmed experimentally, and it is necessary to discuss the possibility of realization and application for the actual system. In this study, our experiment confirms the effectiveness of this control method. For this purpose, an experimental apparatus, which expressed a two degrees of freedom system and consisted of an electromagnetic actuator, a steel beam and two masses, were prepared. A digital signal processor was used for the realization of the parametric excitation control. During the experiments, we confirmed the effectiveness of the control procedure and accuracy of the theoretical results. In addition, the relationships between the ratio of the two masses and the ratio of the natural and the parametric excitation frequency, which are required for the effective control, were cleared. According to this study, the quenching of self-excited vibration by using the parametric excitation is realized within the very narrow band of frequency and the mass ratio should be small.
10
Dohnal, Fadi, Wolfgang Paradeiser, and Horst Ecker. "Experimental Study on Cancelling Self-Excited Vibrations by Parametric Excitation." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-14552.
Full textAbstract:
This article reports on the experimental verification of an anti-resonance effect obtained by parametric stiffness excitation. From theoretical studies it is known that parametric excitation at non-resonant parametric resonances can improve the damping behavior of a mechanical system and even stabilize an otherwise unstable system. To demonstrate this effect, a test setup was designed, based on a two-mass vibration system, gliding on an air track. Parametric stiffness excitation (PSE) was realized by a mechanical device that creates a time-periodic stiffness by modulating the tension in an elastic rubber band. With this device it was possible to demonstrate the improved damping behavior of the system when the PSE device is operating at or near the first parametric combination resonance of difference type. Also, a simple electro-magnetic device was used to create self-exciting forces. It could be shown for the first time that it is indeed possible to stabilize the unstable system by introducing parametric stiffness excitation.