Academic literature on the topic 'Motion; Vibration damping'
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 'Motion; Vibration damping.'
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 "Motion; Vibration damping"
1
Iskakov, Zharilkassin. "SIMULATION OF NON-LINEAR CHARACTERISTICS INFLUENCE DYNAMIC ON VERTICAL RIGID GYRO ROTOR RESONANT OSCILLATIONS." CBU International Conference Proceedings 6 (September 25, 2018): 1094–100. http://dx.doi.org/10.12955/cbup.v6.1319.
Full textAbstract:
The influence of viscous linear and cubic nonlinear damping of an elastic support on the resonance oscillations of a vertical rigid gyroscopic unbalanced rotor is investigated. Simulation results show that linear and cubic non-linear damping can significantly dampen the main harmonic resonant peak. In non-resonant areas where the speed is higher than the critical speed, the cubic non-linear damping can slightly dampen rotor vibration amplitude in contrast to linear damping. If linear or cubic non-linear damping increase in resonant area significantly kills capacity for absolute motion, then they have little or no influence on the capacity for absolute motion in non-resonant areas. The simulation results can be successfully used to create passive vibration isolators used in rotor machines vibration damping, including gyroscopic ones.
2
You, Ki Pyo, Young Moon Kim, Cheol Min Yang, and Dong Pyo Hong. "Increasing Damping Ratios in a Tuned Liquid Damper Using Damping Bars." Key Engineering Materials 353-358 (September 2007): 2652–55. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.2652.
Full textAbstract:
Wind-induced vibration of tall buildings have been of interest in engineering for a long time. Wind-induced vibration of a tall building can be most effectively controlled by using passive control devices. The tuned liquid damper(TLD) is kind of a passive mechanical damper, which relies on the sloshing liquid in a rigid tank. TLD has been successfully employed in practical mitigation of undesirable structural vibrations because it has several potential advantages: low costs, easy installation in existing structures, and effectiveness even against small-amplitude vibrations. Shaking table experiments were conducted to investigate the characteristics of the shallow water sloshing motion in a rectangular tank. To increase the damping ratio of the rectangular water tank, triangle sticks were installed at the bottom of water tank. This installation increased the damping ratio by amaximum of 40-70%.
3
Sarangi, M., B. C. Majumdar, and A. S. Sekhar. "On the Dynamics of Elastohydrodynamic Mixed Lubricated Ball Bearings. Part II: Non-Linear Structural Vibration." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 219, no. 6 (June 1, 2005): 423–33. http://dx.doi.org/10.1243/135065005x34080.
Full textAbstract:
Equations of motion of a ball bearing are formulated in generalized coordinates, using Lagrange's equation considering the vibrational characteristics of the individual constituents such as inner race, outer race, cage, and balls, in order to investigate the structural vibration of the bearing. This article is the second part of the present study dealing with structural vibration, whereas in the first part, elastohydrodynamic mixed lubricated contact stiffness and damping coefficients are determined. Utilizing these stiffness and damping coefficients, a non-linear load-deflection contact model is developed. This is then used in the equations of motion. The equations of motion are solved using Runge-Kutta integration technique. This work differs from the previous studies in the sense that the model simulates the vibration, considering that both the lubricated contact stiffness and damping correspond to the conservative and dissipative energies, respectively. It is observed that under undamped conditions, all the elements of the bearing actively participate in energy sharing and oscillate periodically, containing more than one frequency. The system vibration, however, died down rapidly in the presence of damping.
4
Yu, Jianda, Zhibo Duan, Xiangqi Zhang, and Jian Peng. "Wind-Induced Vibration Control of High-Rise Structures Using Compound Damping Cables." Shock and Vibration 2021 (April 22, 2021): 1–9. http://dx.doi.org/10.1155/2021/5537622.
Full textAbstract:
Based on the vibration reduction mechanism of compound damping cables, this study focuses on the wind-induced vibration control of high-rise structures with additional mass at the top. The differential equation of motion of the system under the action of the composite damping cable is established, and the analytical solution of the additional damping ratio of the structure is deduced, which is verified by model tests. The vibration response of the structure under the action of simple harmonic vortex excitation and randomly fluctuating wind loads is studied, and the effect of different viscous coefficients of the dampers in the composite damping cable and different installation heights of the damping cable on the vibration control is analyzed. The results show that a small vortex excitation force will cause large vibrations of low-dampened towering structures, and the structure will undergo buffeting under the action of wind load pulse force. The damping cable can greatly reduce the amplitude of structural vibration. The root means square of structural vibration displacement varies with damping. The viscosity coefficient of the device and the installation height of the main cable of the damping cable are greatly reduced.
5
Inoue, Masanobu, Isao Yokomichi, and Koju Hiraki. "Particle Damping with Granular Materials for Multi Degree of Freedom System." Shock and Vibration 18, no. 1-2 (2011): 245–56. http://dx.doi.org/10.1155/2011/309682.
Full textAbstract:
A particle damper consists of a bed of granular materials moving in cavities within a multi degree-of-freedom (MDOF) structure. This paper deals with the damping effects on forced vibrations of a MDOF structure provided with the vertical particle dampers. In the analysis, the particle bed is assumed to be a single mass, and the collisions between the granules and the cavities are completely inelastic, i.e., all energy dissipation mechanisms are wrapped into zero coefficient of restitution. To predict the particle damping effect, equations of motion are developed in terms of equivalent single degree-of-freedom (SDOF) system and damper mass with use made of modal approach. In this report, the periodic vibration model comprising sustained contact on or separation of the damper mass from vibrating structure is developed. A digital model is also formulated to simulate the damped motion of the physical system, taking account of all vibration modes. Numerical and experimental studies are made of the damping performance of plural dampers located at selected positions throughout a 3MDOF system. The experimental results confirm numerical prediction that collision between granules and structures is completely inelastic as the contributing mechanism of damping in the vertical vibration. It is found that particle dampers with properly selected mass ratios and clearances effectively suppress the resonance peaks over a wide frequency range.
6
Aoki, Shigeru, and Takeshi Watanabe. "An Investigation of an Impact Vibration Absorber With Hysteresis Damping." Journal of Pressure Vessel Technology 128, no. 4 (February 16, 2006): 508–15. http://dx.doi.org/10.1115/1.2349557.
Full textAbstract:
The dynamic vibration absorber is a device for reducing the vibration of many structures and mechanical equipment. It consists of a small mass which is attached to the primary vibrating system or main mass. The impact damper is one of such dynamic vibration absorbers in which motion of auxiliary mass is limited by motion-limiting stop or placed inside a container. In this paper, in order to consider energy loss for an impact represented by the coefficient of restitution and duration of collision, an analytical model with hysteresis damping is introduced. Using this model, dynamic response of the system under harmonic and that under random excitations are analyzed. Some numerical results are shown.
7
Rezaei DA, Hojjat, Mahmoud Kadkhodaei, and Hassan Nahvi. "Analysis of nonlinear free vibration and damping of a clamped–clamped beam with embedded prestrained shape memory alloy wires." Journal of Intelligent Material Systems and Structures 23, no. 10 (May 6, 2012): 1107–17. http://dx.doi.org/10.1177/1045389x12441509.
Full textAbstract:
Nonlinear free vibration and damping of a clamped–clamped composite beam containing shape memory alloy wires with different prestrains embedded in the midsurface are investigated. The constitutive relations of shape memory alloy are considered in the large deflection response of the elastic Euler–Bernoulli beam, and Hamilton’s principle is used to derive differential equation of the beam motion with extensible midplane. Considering midplane stretching due to tension in the shape memory alloy wires provides an ability to model damping in a nonlinear analysis although there is no distinct damping expression in the governing equation of motion. The results show a gradual decrease in the free vibration amplitude of the beam until it reaches a fully elastic response while this cannot be seen in linear models. Free vibrations of the beam are investigated, and time response, phase diagram, state of stress and strain in the wires, and variations of loss factor are studied. The effect of prestrain in the shape memory alloy wires on the final stable vibration amplitude and loss factor in free vibrations of the beam is also investigated.
8
Zolkiewski, Sławomir, and Leszek Dziczkowski. "Mathematical Model of the Damped Variable Cross Section Beam in Transportation." Advanced Materials Research 837 (November 2013): 517–22. http://dx.doi.org/10.4028/www.scientific.net/amr.837.517.
Full textAbstract:
The paper concerns the problem of vibrations of beamlike system with variable cross section. The beam is treated as the movable system in transportation. The considered problem focuses on modelling and dynamic analysis of geometrically nonlinear beam systems in rotational motion within the context of damping. The major scientific purpose of the paper is to elaborate the mathematical model of such a system. Additionally, the main motion impact on the local vibrations due to the mathematical sense is determined. Moreover, it is necessary to remember the interactions between damping forces of the above mentioned mechanisms and the transportation effect. The main motion of the system is treated as transportation, whereas the vibrations of the system are treated as relative motion. There are two types of systems considered: simple vibrating longitudinally and simple vibrating transversally in the plane transportation. The most interesting elements of the analysis determine the dynamic state of the system and present the mutual coupling of vibration amplitudes, natural frequency, and transportation velocity. Analysis of systems moving with low velocities or vibrating only locally treats the systems as already known models in literature. There are many scientific articles where the forms of vibrations of these systems have been described. Due to the obtained results it will be possible to confront mathematical models with the known stationary and non-stationary systems. As regards complex and simple systems running at high speed, the resonance phenomenon can be noticed, and depending on the amplitude and frequency of vibrations, we consider the following cases: when the amplitude reaches theoretical infinity leading in practice to permanent damage of the mechanism or when the amplitude of vibration reaches a certain speed which can cause the decrease of durability of the whole system. The adequate practical usage of the above mentioned researches is justified by its wide range of applications. In the majority of technical cases, further analysis of the systems is considered to be far too much simplified when we ignore the elements of flexibility, damping, or the nonlinear geometry of the beam. All the mentioned influences are presented in the derived mathematical model in form of equations of motion.
9
Issa, J. S. "Ground motion isolation using a newly designed vibration absorber." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 226, no. 3 (October 12, 2011): 636–47. http://dx.doi.org/10.1177/0954406211417548.
Full textAbstract:
A new vibration absorber setup for vibration attenuation in single degree of freedom systems subjected to harmonic base motion is proposed. The absorber is placed so as to separate between the vibrating ground and the main undamped system. It consists of a mas spring damper directly connected to the vibrating ground. The main system is modelled as a mass spring attached to the absorber's mass. The optimal absorber parameters are determined with the aim of reducing the steady-state amplitude of the main mass. It is shown that the amplitude of the main mass passes through three fixed points, two of which are used in the determination of the optimal shape of the transfer function. One of the fixed points is independent of the damping ratio and the second is independent of both the damping and tuning ratios. For this setup, the solution is not unique since the ultimate design is reached by a complete isolation of the main mass from the moving ground and is attained by removing the absorber's damper and stiffness. Since this solution is not physically achievable, for a given mass ratio of the system, the smallest tuning ratio which ensures structural integrity of the system is selected. The optimal damping ratio which yields the optimal shape of the objective function is determined analytically in terms of the mass and tuning ratios. A design flowchart is presented to be used for the design of such absorbers.
10
Fang, X., and J. Tang. "Granular Damping in Forced Vibration: Qualitative and Quantitative Analyses." Journal of Vibration and Acoustics 128, no. 4 (February 2, 2006): 489–500. http://dx.doi.org/10.1115/1.2203339.
Full textAbstract:
Granular damping is a passive vibration suppression technique which attenuates the response of a vibrating structure by the use of a granule-filled enclosure attached to or embedded in the structure. While promising in many applications especially under harsh conditions, the granular damping mechanism is very complicated and highly nonlinear. In this paper, we perform correlated analytical modeling and numerical studies to evaluate qualitatively and quantitatively the energy dissipation in granular damping. First, an improved analytical model based on the multiphase flow theory is developed for the description of granular motion inside the damper, which accounts for the complete effects of collisions/impacts and dynamic frictions among the granules and between the granules and the enclosure. This model can efficiently characterize the damping effect with high fidelity over a very wide range of parameters, and thus can be used to develop guidelines for parametric studies. With this as a basis, detailed numerical studies using the discrete element method are also carried out to analyze the underlying mechanisms and then provide mechanistic insight for granular damping. In this paper, we focus our attention on the granular damping effect on forced vibrations, which has potential application to a variety of systems.
Dissertations / Theses on the topic "Motion; Vibration damping"
1
Palmborg, John, and Hampus Söderman. "Vibration damping of alpine skis with implemented Flow Motion Technology." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-263873.
Full textAbstract:
Flow Motion Technology AB has previously developed a technology to improve hockey skates and inlines. The technology called Flow Motion Technology (FMT) is utilizing the smooth and effective rolling motion of a human footstep, and has proven to be very successful after implementation in both hockey skates and inlines. Flow Motion Technology AB has interest in investigating whether the technology can be implemented in other sports applications, which this thesis project concerns. The project examines the implementation of FMT in the alpine skiing segment. The purpose is to provide Flow Motion Technology AB with a foundation for evaluating the potential of investing further in the development of FMT applied in alpine skiing. FMT is implemented in a feature positioned between ski and binding of most alpine race skis, commonly called a race plate. The work is divided into two parts; The first part covers the development and manufacturing of a prototype along with detailed description of the procedures and methods used. The second part is about the tests of the prototype’s vibration-damping properties carried out in laboratory environment along with analysis of the results. Initial field tests are also carried out followed by fundamental analysis. An existing plate intended for competition use is tested in parallel with the prototype and is used as a reference when analyzing the results. The results show that the ski equipped with the FMT plate dampened vibrations on an average of 27 % faster than the reference plate. Measurements was compiled for three damping intervals specified for the tests performed in laboratory. A statistically significant difference in all three cases was obtained. The measured maximum amplitude of the acceleration in the vibrations was also significantly lower for the ski implemented with the FMT plate compared to the reference plate. The eigen frequencies of the ski measured in laboratory were not significantly affected if the ski was fitted with the FMT plate or the reference plate. The eigen frequencies measured in field generally corresponded to the measured in laboratory, with the difference that they were offset on an average of 7 Hz higher in field.Flow Motion Technology AB har tidigare utvecklat en teknologi för att förbättra hockeyskridskor och inlines. Teknologin kallad Flow Motion Technology (FMT) utnyttjar den naturliga och effektiva rullande rörelse i en människas fotsteg, och har efter implementation i hockeyskridskor och inlines visat sig vara framgångsrik. Flow Motion Technology AB vill undersöka om denna teknologi kan implementeras i andra idrottssammanhang för att utvärdera möjligheter att bredda företagets affärsområde. Detta examensarbete är en del av denna undersökning, och i denna rapport beskrivs implementationen av FMT i segmentet alpinskidåkning. Syftet med projektet är att förse Flow Motion Technology AB med underlag för att utvärdera lönsamheten i att investera mer i utvecklingen av FMT riktad mot alpinskidåkning. FMT implementeras i projektet i en raceplatta, en komponent monterad mellan skida och bindning. Arbetet är uppdelat i två delar; utveckling och tillverkning av en funktionsprototyp med detaljerad beskrivning av tillvägagångssätt och metoder, samt tester av prototypens vibrationsdämpande prestanda i labbmiljö med tillhörande analys av resultat. Initiala tester utförs även i fält med enklare analys av resultat. En befintlig bindningsplatta avsedd för tävling testas parallellt med den utvecklade plattan och används som referens vid analys av resultaten. Resultaten visar att plattan implementerad med FMT dämpade en skidas vibrationer i genomsnitt 27 % snabbare än vad referensplattan gjorde vid de tre dämpningsintervall som specificerats för testen i labbmiljö. En statistiskt signifikant skillnad i alla tre fall. Den uppmätta maxamplituden för accelerationen i vibrationerna var även statistiskt signifikant lägre för skidan implementerad med FMT jämfört med referensplattan. Egenfrekvenserna uppmätta i labb påverkades inte nämnvärt om skidan var monterad med FMT-plattan eller referensplattan. De egenfrekvenser som uppmättes i fält motsvarade generellt de som uppmättes i labb med skillnaden att de var förskjutna till att i genomsnitt vara 7 Hz högre.
2
Gonsalves, Diane Helen. "Chaos concepts in mechanical systems with clearances." Thesis, University of Aberdeen, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387216.
Full textAbstract:
This thesis considers the use of chaos concepts in investigating the dynamics of two discontinuously nonlinear mechanical systems having two degrees of freedom. The nonlinearity considered is in the form of a discontinuous stiffness effect, and can cause the systems to exhibit chaotic motion. The first system is a rotor system with a bearing clearance effect. The second is a nonlinear vibration absorber, comprising a conventional linear absorber and a linear snubber stiffness, which the auxiliary mass intermittently contacts. Numerical integration is used in solving the equations of motion for each system. Equivalent physical rigs are tested. Both the theoretical and experimental results are analysed using chaos techniques such as phase plane portraits, Poincaré maps, frequency spectra and bifurcation diagrams. Comparison made between the differently acquired results shows that fairly good correlation is obtained in both systems, for realistic values of damping. Periodic, quasiperiodic and chaotic responses are exhibited by both systems, for different combinations of system parameters, with the responses of the systems being extremely sensitive to changes in these parameters. Investigations of the rotor system concluded that quasi-periodic responses are only possible if there is some form of cross-coupling present. An effective discontinuously nonlinear absorber is developed, theoretically. A reduction in the amplitude of the second resonance peak of the linear absorber is achieved. This enables the primary system to be operated over a wider frequency range without reaching the large amplitudes to the second resonance. The non-linear absorber also has the effect of attenuating the response from the auxiliary mass. Fatigue analysis is carried out to investigate the effect of chaotic motions on mechanical components. The analysis reveals the subharmonic motions are more damaging than chaotic motions, which are in turn more damaging than simple fundamental responses.
Book chapters on the topic "Motion; Vibration damping"
1
"OPTIMAL DAMPING OF TRANSIENT MOTION IN MULTIDEGREE-OF-FREEDOM SYSTEMS." In Optimal Protection from Impact, Shock and Vibration, 253–86. CRC Press, 2001. http://dx.doi.org/10.1201/9781482283358-14.
Full text
2
Carlos de Carvalho Pereira, José. "Energy Harvesting Prediction from Piezoelectric Materials with a Dynamic System Model." In Piezoelectric Actuators - Principles, Design, Experiments and Applications [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96626.
Full textAbstract:
Piezoelectric vibration energy harvesting has been investigated for different applications due to the amount of wasted vibration from dynamic systems. In the case of piezoelectric materials, this energy lost to the environment can be recovered through the vibration of energy harvesting devices, which convert mechanical vibration into useful electrical energy. In this context, this chapter aims to present the mechanical/electrical coupling on a simple dynamic system model in which a linear piezoelectric material model is incorporated. For this purpose, a mechanical/electrical element of a piezoelectric disk is developed and integrated into a lumped mass, viscous damping, and spring assembling, similar to a quarter car suspension system. Equations of motion for this dynamic system in the time domain can be solved using the finite element method. The recovered electric power and energy density for PZT (Lead Zirconate Titanate) from the wasted vibration can be predicted considering that the road roughness is introduced as an input mode.
3
BISHOP, R. E. D., and W. G. PRICE. "A Note on Hysteretic Damping of Transient Motions." In Random Vibration-Status and Recent Developments - The Stephen Harry Crandall Festschrift, 39–45. Elsevier, 1986. http://dx.doi.org/10.1016/b978-0-444-42665-9.50009-8.
Full textConference papers on the topic "Motion; Vibration damping"
1
Liang, Changwei, You Wu, and Lei Zuo. "Vibration Energy Harvesting System With Mechanical Motion Rectifier." In ASME 2015 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/dscc2015-9837.
Full textAbstract:
Mechanical motion rectifier (MMR) has been used as power takeoff system to harvest energy for different applications. The dynamics of single degree of freedom energy harvesting system with MMR is piecewise linear due to the engagement and disengagement of one-way clutches. The energy harvesting performance of single degree of freedom system with MMR under force and motion excitation are studied and compared with ideal linear damping and non-MMR system in this paper. Under harmonic force and motion excitation, the optimal excitation frequency and output power of MMR system is less sensitive to the power takeoff inertia compared with non-MMR system. Furthermore, the output power of MMR system under harmonic motion excitation is larger than non-MMR system. The performance index of MMR, non-MMR and linear damping systems are compared under random excitation. It is found that MMR system has a better performance over both non-MMR and linear damping system, which makes it a better choice for energy harvesting.
2
Aoki, Shigeru, and Takeshi Watanabe. "An Investigation of an Impact Vibration Absorber With Hysteresis Damping." In ASME 2005 Pressure Vessels and Piping Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/pvp2005-71280.
Full textAbstract:
The dynamic vibration absorber is a device for reducing the vibration of many structures and mechanical equipment. It consists of a small mass which is attached to the primary vibrating system or main mass. The impact damper is one of such dynamic vibration absorbers in which motion of auxiliary mass is limited by motion-limiting stop or placed inside a container. In this paper, in order to consider energy loss for an impact represented by the coefficient of restitution and duration of collision, an analytical model with hystresis damping is introduced. Using this model, dynamic response of the system under harmonic and that under random excitations are analyzed. Some numerical results are shown.
3
Janzen, V. P., Y. Han, B. A. W. Smith, and S. M. Fluit. "Vibration Damping of Stabilized Steam-Generator Tubes." In ASME 2005 Pressure Vessels and Piping Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/pvp2005-71666.
Full textAbstract:
The integrity of steam-generator tubes is an important aspect of the long-term reliable operation of nuclear power plants. In situations where a tube is judged to be at risk, it must be either plugged, or removed, or reliably stabilized in some manner to avoid excessive motion of the tube due to flow-induced vibration. The present work describes measurements of the effect of an internal cable-type stabilizer on the structural damping of steam-generator tubes. The free-vibration response of unstabilized and stabilized tubes was analyzed to provide damping ratios from frequency-domain spectral responses, time-domain logarithmic decrement ratios and time-domain vibration decay-curves. The structural damping ratios typically increased from approximately 1.6% to approximately 4.3% with the addition of the stabilizer. This last value is somewhat less than recently published values for stabilized tubes from a different type of steam generator, suggesting that tube stabilization, while effective, has limitations that need to be conservatively assessed.
4
Mizuno, Takeshi, Satoru Yamamoto, Yuji Ishino, and Masaya Takasaki. "Damping-Insensitive Mass Measurement Using a Damped Dynamic Vibration Absorber." In ASME 2012 5th Annual Dynamic Systems and Control Conference joint with the JSME 2012 11th Motion and Vibration Conference. ASME, 2012. http://dx.doi.org/10.1115/dscc2012-movic2012-8823.
Full text
5
Issa, Jimmy S. "A Modified Optimal Design of a Vibration Absorber for Ground Motion Isolation." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36500.
Full textAbstract:
Recently, a new vibration absorber setup was proposed where the absorber is placed between the dynamic system and its moving support. The problem was solved and design guidelines were proposed using the classical absorber design technique. In this work, the unique optimal absorber parameters are determined with the aim of minimizing the maximum of the primary system amplitude. For a given stiffness ratio of the system, the optimal mass and damping ratios are obtained analytically using an optimization method based on invariant points of the objective function. Similar to the case of the classical vibration absorber setup, these points are independent of the system damping ratio. It is shown that a trade-off relationship exists between these points, therefore the optimal mass ratio is determined first by a proper placement of the invariant points. Two suboptimal damping ratios are determined by forcing one of the two peaks of the objective function to coincide with one of the invariant points. Then, the optimal damping ratio is obtained from the average of the two suboptimal damping ratios. This approximate analytical solution is validated through comparison with the exact optimal parameters which were calculated numerically using two different numerical optimization methods. The first is based on the genetic algorithm technique and the second on the downhill simplex method. The optimal parameters are plotted and several examples are considered where the objective function is plotted in its approximate and exact optimal shapes.
6
Cheng, Ming, Zhaobo Chen, and S. Nima Mahmoodi. "Experimental Investigation on Vibration Damping Characteristics of Magnetorheological Damper." In ASME 2018 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/dscc2018-9214.
Full textAbstract:
This paper studies the vibration damping characteristics of a magnetorheological (MR) damper. A single-degree-of-freedom vibration isolation system with pedestal motion containing MR dampers has been experimentally investigated. Results show that the transmissibility at the resonance frequency does not constantly decrease as expected. It gradually decreases at the beginning, then increase unexpectedly as the input current increases. In addition, the resonant frequency of the system increases continuously. In order to explore the mechanism behind the experimental phenomenon, a centralized parameterized model of the MR damper is established. Hardening coefficient, a parameter that characterizes the dynamic characteristics of the MR damper is introduced, and the influence of the structural parameters and dynamic parameters of the MR damper on the hardening coefficient is analyzed. Simultaneously, a dynamic model of the MR damper is derived based on the Bingham model, and the damping characteristics of the MR damper are predicted and compared with the experimental results. Further, based on a simplified and equivalent dynamic model of the system, the relationship between transmissibility of the system and load mass, stiffness, and damping reveals the physical laws behind the experimental phenomenon. Finally, theoretical results are derived and compared with the experimental results, which demonstrates the rationality of the theoretical analysis.
7
Mahmoodi, S. Nima, Siamak E. Khadem, and Ebrahim Esmailzadeh. "Equations of Nonlinear Motion of Viscoelastic Beams." In ASME 2005 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/detc2005-84944.
Full textAbstract:
A viscoelastic nonlinear beam with cubic nonlinearities is considered. In order to obtain the equations of nonlinear motion of the beam for large deformation vibrations, the Lagrangian dynamics and Hamilton principle is used. It is considered that the beam vibrates in two directions, one in longitudinal direction and the other in the transverse direction. Large amplitude vibrations cause the nonlinearities in inertia and geometry terms. Also, due to viscoelastic property of the beam, a nonlinear damping term is appeared in the equations of motion. Using the condition of inextensible beams, the equation of motion and boundary conditions of bending vibration of a Kelvin-Voigt viscoelastic beam has been obtained. Finally, if one considers the damping coefficient to be equal to zero in the obtained equation of motion of viscoelastic system then, an equation of motion for the elastic beam will be obtained.
8
Hamidzadeh, Hamid R. "Attenuation of Free Vibration Using Particle Impact Damper." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-42731.
Full textAbstract:
The particle impact damper is an effective vibration damping treatment that can be used in the cases where visco-elastic constrained layer damping fails due to excessive surrounding temperature. In this type of passive damping, particles move in a container attached to the vibrating system resulting in plastic impact with the container. In the presented theoretical study, the damping characteristics of free oscillation for a vertical system with an initial displacement are considered and a governing equation for the system under free vibration with a particle damper is derived. To evaluate the damping characteristics for the free vibrating system, the equivalent damping ratio is determined by considering both kinematics and kinetics of the particle motion and its impacts with the container. The presented solution concludes that in general damping effectiveness can be enhanced by increasing the mass of the particle in comparison with total mass of the system. Mathematical optimum clearance for the moving particle and the equivalent viscous damping ratio are determined for the best performance of the particle impact damper.
9
Park, Juchirl, and John A. Peterson. "Noise and Vibration Reduction on the Single Axis Adaptive Damping Controls." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-62428.
Full textAbstract:
Reducing or eliminating seat noise and vibration are the main objectives of a semi-active damping system implemented in a commercial vehicle seat. The system must be developed such that control forces minimize seat motion. Abrupt motion with semi-active damping systems is typically called ‘dynamic jerk.’ Semi-active damping in a seat application places the control forces close to the seat occupant so there is less ‘filtering’ to protect the human from feeling dynamic jerk. Whereas in an automotive suspension there might be more tolerance for dynamic jerk because the comparatively heavy vehicle body acts to filter some of the dynamic jerk and the interaction of the tire and road input may also mask it. In this research, dynamic jerk has been addressed and studied for the advanced SEAT application. The seat has been tested with varying sine inputs at specific amplitudes. The response of the semi-active damping seat system has been analyzed to characterize dynamic jerk and a control algorithm has been developed to minimize this undesirable response. The conclusion is that dynamic jerk is dependent on the damper’s physical properties as well as the system’s sensors. A Design of Experiments statistical study was carried out to determine what are the most influencing factors. Limiting the range of damping force reduces the control authority; however, allowing full damping force may trigger dynamic jerk. Identifying the dynamic jerk plays an important role in order to have the indication of the properly tuned system. In this research, the identification strategy of the dynamic jerk is studied and developed.
10
Siewert, Christian, Lars Panning, Christoph Gerber, and Pierre-Alain Masserey. "Numerical and Experimental Damping Prediction of a Nonlinearly Coupled Low Pressure Steam Turbine Blading." In ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-51073.
Full textAbstract:
The rotor blades of a low pressure steam turbine stage are subjected to fluctuating steam forces during operation that cause blade vibrations. One of the main tasks in the design of low pressure steam turbine blading is the vibration amplitude reduction in order to avoid high dynamic stresses that could damage the blading. The vibration amplitudes of the blades in the last row of a low pressure steam turbine stage can be reduced significantly to a reasonable amount if adjacent blades are coupled by shroud and snubber contacts that reinforce the blading. Furthermore, in the case of blade vibrations, relative displacements between neighboring blades occur in the contacts and friction forces are generated that provide additional damping to the structure due to the energy dissipation caused by microslip effects. A three dimensional structural dynamics model including an appropriate spatial contact model is necessary to predict the generalized contact forces induced by the shroud and the snubber contacts and to describe the vibrational behavior of the blading with sufficient accuracy. To reduce the numerical effort to compute the vibration response, the Harmonic Balance Method (HBM) is applied to solve the resulting nonlinear equations of motion in the frequency domain.
Reports on the topic "Motion; Vibration damping"
1
Yerganian, S. S. Characterization of the Damping of a Free Vibrating Piezoelectric Motor Stator by Displacement Measurements. Office of Scientific and Technical Information (OSTI), October 1999. http://dx.doi.org/10.2172/13897.
Full text