Passive Control of Vibration of Elastically Supported Beams Subjected to Moving Loads

2005 ◽  
Author(s):  
D. Younesian ◽  
E. Esmailzadeh ◽  
M. H. Kargarnovin
Keyword(s):  
High Speed ◽  
Passive Control ◽  
Vibration Suppression ◽  
Damping Ratio ◽  
Equations Of Motion ◽  
Compressive Force ◽  
Moving Loads ◽  
Axial Compressive Force ◽  
Before And After ◽  
Elastically Supported

Vibration suppression of elastically supported beams subjected to moving loads is investigated in this work. For a Timoshenko beam with an arbitrary number of elastic supports, subjected to a constant axial compressive force, and having a tuned mass damper (TMD) installed at the mid-span, the equations of motion are derived and using the Galerkin approach the solution is sought. The optimum values of the frequency and damping ratio are determined both analytically and numerically and presented as some design curves directly applicable in the TMD design for bridge structures. To show the efficiency of the designed TMD, computer simulation for two real bridges, subjected to a S.K.S Japanese high-speed train, is carried out and the results obtained are compared for before and after the installation of the TMD system.

Vibration Analysis and Control of a Rotating Flexible Arm With ACLD Treatment

2002 ◽  
Author(s):  
E. H. K. Fung ◽  
D. T. W. Yau
Keyword(s):  
Vibration Suppression ◽  
Damping Ratio ◽  
Equations Of Motion ◽  
Gravitational Effect ◽  
Transverse Displacement ◽  
Complex Eigenvalue ◽  
Constrained Layer Damping ◽  
Rotating Speed ◽  
Centrifugal Stiffening ◽  
And Control

In this paper, the vibration behavior and control of a clamped-free rotating flexible cantilever arm with fully covered Active Constrained Layer Damping (ACLD) treatment is investigated. The arm is rotating in a horizontal plane in which the gravitational effect and rotary inertia are neglected. The stress-strain relationship for the viscoelastic material (VEM) is described by a complex shear modulus while the shear deformations in the two piezoelectric layers are neglected. Hamilton’s principle in conjunction with finite element method (FEM) is used to derive the nonlinear coupled differential equations of motion and the associated boundary conditions that describe the rigid hub angle rotation, the arm transverse displacement and the axial deformations of the three-layer composite. This refined model takes into account the effects of centrifugal stiffening due to the rotation of the beam and the potential energies of the VEM due to extension and bending. Active controllers are designed with PD for the piezo-sensor and actuator. The vibration frequencies and damping factors of the closed-loop beam/ACLD system are obtained after solving the characteristic complex eigenvalue problem numerically. The effects of different rotating speed, thickness ratio and loss factor of the VEM as well as different controller gain on the damped frequency and damping ratio are presented. The results of this study will be useful in the design of adaptive and smart structures for vibration suppression and control in rotating structures such as rotorcraft blades or robotic arms.

scholarly journals Seismic Performance Analysis of Tuned Mass Rocking Wall (TMRW)-Frame Building Structures

Buildings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 293
Author(s):  
Andong Wang ◽  
Shanghong Chen ◽  
Wei Lin ◽  
Ai Qi
Keyword(s):  
Seismic Performance ◽  
Frequency Ratio ◽  
Passive Control ◽  
Damping Ratio ◽  
Equations Of Motion ◽  
Control Device ◽  
Building Structures ◽  
Frame Building ◽  
Host Structure ◽  
Rocking Wall

A tuned mass rocking wall (TMRW) is a passive control device that combines the merits of a traditional tuned mass damper (TMD) and a traditional rocking wall (RW). TMRWs not only help avoid weak story failure of the host structure but can also be regarded as a largely tuned mass substructure in the building structure. Through the appropriate design of the frequency ratio, the host structure can dissipate much more energy under earthquake excitations. In this paper, the basic equations of motion for the mechanical model of an SDOF structure-rigid rocking wall are established, and the optimization formulas of frequency ratio and damping ratio of TMRW are derived. Through the dynamic elastoplastic analysis of a six-story TMRW-frame model, the applicability of the derived parameter optimization formulas and the effectiveness of the TMRW in seismic performance control are investigated. The results demonstrate that the TMRW can coordinate the uneven displacement angle between stories of the host structure. Additionally, the TMRW is found to possess the merit of reducing both the peak and root-mean-square (RMS) structural responses when subjected to different types of earthquake excitations.

Passive Control of Critical Speeds of a Rotating Shaft Using Eccentric Sleeves: Model Development

2016 ◽  
Author(s):  
A. J. Kirk ◽  
J. Griffiths ◽  
C. Bingham ◽  
G. Knowles ◽  
R. Bickerton
Keyword(s):  
High Speed ◽  
Passive Control ◽  
Equations Of Motion ◽  
Variable Mass ◽  
Model Development ◽  
Three Dimensional ◽  
Practical Case ◽  
Rotating Shaft ◽  
Critical Speeds ◽  
Rotating Shafts

This paper considers the passive control of lateral critical speeds in high-speed rotating shafts through application of eccentric balancing sleeves. Equations of motion for a rotating flexible shaft with eccentric sleeves at the free ends are derived using the extended Hamilton Principle, considering inertial, non-constant rotating speed, Coriolis and centrifugal effects. A detailed analysis of the passive control characteristics of the eccentric sleeve mechanism and its impact on the shaft dynamics, is presented. Results of the analysis are compared with those from three-dimensional finite element simulations for 3 practical case studies. Through a comparison and evaluation of the relative differences in critical speeds from both approaches it is shown that consideration of eccentric sleeve flexibility becomes progressively more important with increasing sleeve length. The study shows that the critical speed of high-speed rotating shafts can be effectively controlled through implementation of variable mass/stiffness eccentric sleeve systems.

Passive and Switched Stiffness Vibration Controllers Using Fluidic Flexible Matrix Composites

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Amir Lotfi-Gaskarimahalle ◽  
Lloyd H. Scarborough ◽  
Christopher D. Rahn ◽  
Edward C. Smith
Keyword(s):  
Passive Control ◽  
Axial Strain ◽  
Damping Ratio ◽  
Equations Of Motion ◽  
Absolute Error ◽  
Step Response ◽  
Axial Stiffness ◽  
Matrix Composites ◽  
Mass System ◽  
Valve Orifice

This paper investigates passive and semi-active vibration control using fluidic flexible matrix composites (F2MC). F2MC tubes filled with fluid and connected to an accumulator through a fixed orifice can provide damping forces in response to axial strain. If the orifice is actively controlled, the stiffness of F2MC tubes can be dynamically switched from soft to stiff by opening and closing an on/off valve. Fiber reinforcement of the F2MC tube kinematically relates the internal volume to axial strain. With an open valve, the fluid in the tube is free to move in or out of the tube, so the stiffness is low. With a closed valve, however, the high bulk modulus fluid resists volume change and produces high axial stiffness. The equations of motion of an F2MC-mass system are derived using a 3D elasticity model and the energy method. The stability of the unforced dynamic system is proven using a Lyapunov approach. A reduced-order model for operation with either a fully open or fully closed valve motivates the development of a zero vibration (ZV) controller that suppresses vibration in finite time. Coupling of a fluid-filled F2MC tube to a pressurized accumulator through a fixed orifice is shown to provide significant passive damping. The open-valve orifice size is optimized for optimal passive, skyhook, and ZV controllers by minimizing the integral time absolute error cost function. Simulation results show that the optimal open valve orifice provides a damping ratio of 0.35 compared with no damping in closed-valve case. The optimal ZV controller outperforms optimal passive and skyhook controllers by 32.9% and 34.2% for impulse and 34.7% and 60% for step response, respectively. Theoretical results are confirmed by experiments that demonstrate the improved damping provided by optimal passive control F2MC and fast transient response provided by semi-active ZV control.

Application of the Nonlinear Energy Sink Systems in Vibration Suppression of Railway Bridges

2010 ◽  
Author(s):  
Davood Younesian ◽  
Amir Nankali ◽  
M. Emad Motieyan
Keyword(s):  
Passive Control ◽  
Vibration Suppression ◽  
Nonlinear Energy Sink ◽  
Solution Technique ◽  
Moving Loads ◽  
Railway Bridges ◽  
Energy Sink ◽  
And Performance ◽  
Euler Bernoulli Beam ◽  
Nonlinear Energy

Vibration suppression of railway bridges using nonlinear energy sink systems (NES) is studied in this paper. Train is modeled as a set of successive moving loads traveling on an Euler-Bernoulli beam. Energy sink as a new passive control strategy is employed as the suppression system. Galerkin method here is adopted as the solution technique. Within a parametric study, series of numerical simulations are carried out and performance of the passive control system is investigated. It is numerically found that an appropriately designed NES can passively reduce the displacement of the bridge up to 43%.

On the Vibration Suppression and Energy Harvesting of Building Structures Using an Electromagnetic-Inerter-Absorber

2018 ◽  
Author(s):  
Eshagh F. Joubaneh ◽  
Oumar R. Barry ◽  
Lei Zuo
Keyword(s):  
Energy Harvesting ◽  
Vibration Suppression ◽  
Damping Ratio ◽  
Equations Of Motion ◽  
Optimization Technique ◽  
Building Structures ◽  
Earthquake Excitation ◽  
Mechanical Coupling ◽  
Rlc Circuit ◽  
Tuning Ratio

This paper studies the performance of an electromagnetic resonant shunt tuned mass-damper-inerter (ERS-TMDI) in terms of simultaneously suppressing unwanted vibration and harvesting energy in a vibrating building. The ERS-TMDI is attached to a building, which is subjected to an earthquake excitation. An inerter is connected between the TMD and the ground. The electromagnetic transducer and associated circuit, which replaces the viscous damping in the classical tuned mas-damper (TMD), is assumed to be an ideal transducer shunted with a resistor, an inductor, and a capacitor (RLC) circuit. Two RLC circuit configurations are investigated: one in series and another in parallel. The governing equations of motion are presented and H2 optimization technique is employed to derive explicit expressions for the optimal mechanical tuning ratio, electrical damping ratio, electrical tuning ratio, and electromagnetic mechanical coupling coefficient. The validity of the obtained closed-form expressions is examined using Matlab optimization toolbox. Parametric studies are carried out to investigate the effect of the mass and inertance ratios on the obtained optimal parameters. Numerical examples are also conducted to demonstrate the role of key design variables on vibration mitigation and energy harvesting performances. Also, the performance of a parallel RLC circuit configuration is compared to that of a series configuration.

An Eigensystem Realization Algorithm for Modal Parameter Identification of a Vertical-Shaft High-Speed Centrifugal Machine

2020 ◽  
Author(s):  
Sina Piramoon ◽  
Mohammad A. Ayoubi
Keyword(s):  
High Speed ◽  
Vibration Suppression ◽  
Damping Ratio ◽  
Mode Shapes ◽  
Modal Parameters ◽  
Modal Parameter ◽  
Eigensystem Realization Algorithm ◽  
Minimum Order ◽  
Markov Parameters ◽  
Centrifugal Machine

Abstract In this paper, we utilize the observer/Kalman filter identification (OKID) and the eigensystem realization algorithm (ERA) techniques to identify the modal parameters of a centrifugal machine. To this end, we use an experimental setup to generate a pseudo-impulse input and collect output measurements which are corrupted by noise. We use the pseudo-impulse input and the OKID to find the Markov parameters of the system. Then we form the Hankel matrix of the system and determine the singular values of the system. A minimum-order, state-space model of the system is realized through the Markov parameters and then the natural frequency, damping ratio, mode shapes, and modal amplitudes at the sensor location are estimated by the ERA. We find three models for three separate cases and validate all the three identified models with the measured data and the Waterfall plot. The identified models are useful for designing passive or active vibration suppression control and fault detection systems. The results confirm that OKID/ERA is a reliable time-domain method for identifying the modal parameters of vertical centrifuge machines.

Analytical Solution to Vertical Dynamic Response of Simply Supported Beam Bridge Traversed by Successive Moving Loads

2012 ◽  
Vol 178-181 ◽  
pp. 2345-2352 ◽  
Author(s):  
Zhi Jun Zhang ◽  
Jin Feng Wu ◽  
Li Zhong Song ◽  
Song Hua Ma ◽  
Xiao Zhen Li
Keyword(s):  
Analytical Solution ◽  
Dynamic Response ◽  
High Speed ◽  
Damping Ratio ◽  
Moving Loads ◽  
Simply Supported Beam ◽  
Railway Bridges ◽  
Simply Supported ◽  
High Speed Trains ◽  
Analytical Expressions

In this paper, vibration theory is used to deduce vertical vibration’s analytical expressions of Euler- Bernoulli beam traveled by moving loads. In the analytical expression, the influences of the train’s travelling speed ,the mode of vibration ,the mass and rigidity of beam itself and the damping ratio of the system are considered comprehensively. Then the calculating program is made with MATLAB to analyze the dynamic response of a bridge as an illustrative example, so as to check the correctness of the analytical solution. Then a 32 meters simply supported beam traversed by moving loads of 8 ICE3 motor cars is analyzed. The calculation results show that the analysis method in this paper can really give accurate results to the beam subjected to arbitrarily spacing loads . The analytical expressions can be applied to preliminary design of railway bridges and assessment of the expected maximum vibration levels under high-speed trains.

Design of a slender turning cutting tool via a vibration absorber equipped with piezoelectric ceramic

2021 ◽  
pp. 107754632110144
Author(s):  
Yiqing Yang ◽  
Haoyang Gao ◽  
Qiang Liu
Keyword(s):  
Piezoelectric Ceramic ◽  
Cutting Tool ◽  
Vibration Suppression ◽  
Equations Of Motion ◽  
Electrical Energy ◽  
Diameter Ratio ◽  
Vibration Absorber ◽  
Machined Surface ◽  
Structural Part ◽  
Machined Surface Roughness

Turning cutting tool with large length–diameter ratio has been essential when machining structural part with deep cavity and in-depth hole features. However, chatter vibration is apt to occur with the increase of tool overhang. A slender turning cutting tool with a length–diameter ratio of 7 is developed by using a vibration absorber equipped with piezoelectric ceramic. The vibration absorber has dual functions of vibration transfer to the absorber mass and vibration conversion to the electrical energy via the piezoelectric effect. Equations of motion are established considering the dual damping from the piezoelectric ceramic and rubber gasket. The equivalent damping of piezoelectric ceramic is derived, and the geometries are optimized to achieve optimal vibration suppression. The modal analysis demonstrates that the cutting tool with the vibration absorber can reach 80.1% magnitude reduction. Machining tests are carried out in the end. The machining acceleration and machined surface roughness validate the vibration suppression of the VA, and the output voltage by the piezoelectric ceramic demonstrates the ability of vibration sensing.

scholarly journals A Critical Review of Supersonic Flow Control for High-Speed Applications

2021 ◽  
Vol 11 (15) ◽  
pp. 6899
Author(s):  
Abdul Aabid ◽  
Sher Afghan Khan ◽  
Muneer Baig
Keyword(s):  
Supersonic Flow ◽  
Flow Control ◽  
Active Control ◽  
Critical Review ◽  
High Speed ◽  
Passive Control ◽  
Control Method ◽  
Sudden Expansion ◽  
Control Approach ◽  
Cost Efficient

In high-speed fluid dynamics, base pressure controls find many engineering applications, such as in the automobile and defense industries. Several studies have been reported on flow control with sudden expansion duct. Passive control was found to be more beneficial in the last four decades and is used in devices such as cavities, ribs, aerospikes, etc., but these need additional control mechanics and objects to control the flow. Therefore, in the last two decades, the active control method has been used via a microjet controller at the base region of the suddenly expanded duct of the convergent–divergent (CD) nozzle to control the flow, which was found to be a cost-efficient and energy-saving method. Hence, in this paper, a systemic literature review is conducted to investigate the research gap by reviewing the exhaustive work on the active control of high-speed aerodynamic flows from the nozzle as the major focus. Additionally, a basic idea about the nozzle and its configuration is discussed, and the passive control method for the control of flow, jet and noise are represented in order to investigate the existing contributions in supersonic speed applications. A critical review of the last two decades considering the challenges and limitations in this field is expressed. As a contribution, some major and minor gaps are introduced, and we plot the research trends in this field. As a result, this review can serve as guidance and an opportunity for scholars who want to use an active control approach via microjets for supersonic flow problems.

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