The Gyroscopic Vibration Absorber

1967 ◽  
Vol 89 (4) ◽  
pp. 706-712
Author(s):  
Robert Jones
Keyword(s):  
Linear Function ◽  
Equations Of Motion ◽  
Experimental Results ◽  
Vibration Absorber ◽  
Variable Frequency ◽  
Equivalent Weight ◽  
Support Structure ◽  
Linearized Equations ◽  
Vibration Excitation ◽  
Analytical Results

The linearized equations of motion of the gyroscopic vibration absorber are derived showing that the antiresonant frequency is a linear function of the speed of the gyroscopic disk; thus the gyroscopic vibration absorber (GVA) can be easily synchronized and therefore applied to vehicles and machinery having variable frequency vibration excitation. The effects on the antiresonant frequency from elastic restraint about the pivots and flexibility in the support structure are also examined. The bandwidth of the GVA is compared to a Frahm absorber of equivalent weight. Experimental results confirm the analytical results and show the feasibility of the GVA as a synchronous absorber.

Pendulum as Vibration Absorber for Flexible Structures: Experiments and Theory

1996 ◽  
Vol 118 (4) ◽  
pp. 558-566 ◽  
Author(s):  
O. Cuvalci ◽  
A. Ertas
Keyword(s):  
Energy Transfer ◽  
Coupling Effect ◽  
Equations Of Motion ◽  
Flexible Structures ◽  
Experimental Results ◽  
Vibration Absorber ◽  
Pendulum System ◽  
Nonlinear Equations Of Motion ◽  
Tip Mass ◽  
Sinusoidal Excitation

The dynamic response of a beam-tip mass-pendulum system subjected to a sinusoidal excitation is investigated. A simple pendulum mounted to a tip mass of a beam is used as a vibration absorber. The nonlinear equations of motion are developed to investigate the autoparametric interaction between the first two modes of the system. The nonlinear terms appear due to the curvature of the beam and the coupling effect between the beam and pendulum. Complete energy transfer between modes is shown to occur when the beam frequency is twice the pendulum frequency. Experimental results are compared with a theoretical solution obtained using numerical integration. The experimental results are in qualitative agreement with the theory.

Experimental Synchronization Study of the Gyroscopic Vibration Absorber

1974 ◽  
Vol 96 (3) ◽  
pp. 983-987
Author(s):  
J. E. Sneckenberger ◽  
H. W. Butler ◽  
In-Meei Neou
Keyword(s):  
Theoretical Consideration ◽  
Laboratory Tests ◽  
Equations Of Motion ◽  
Experimental Results ◽  
Vibration Absorber ◽  
Governing Equations ◽  
Experimental Development ◽  
Moments Of Inertia ◽  
Excitation Frequencies

Analysis of the Gyroscopic Vibration Absorber (GVA) is made with a view to improve its effectiveness as a linear synchronous absorber. Theoretical consideration reveals that much of the nonlinearity of the governing equations of motion of the structure-absorber system involves terms containing an absorber parameter IE. The experimental development of a GVA for which this parameter is made to vanish by appropriate proportionment of certain absorber moments of inertia is shown to be feasible. Laboratory tests examining the nulling potential of this experimental GVA show that linear synchronization of the antiresonant frequency to the speed of the GVA rotor can be obtained for a wider range of excitation frequencies than when the absorber parameter is not equal to zero. Comparison of the experimental results with analytical predictions is also favorable.

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.

On the Parametric Excitation of Pendulum-Type Vibration Absorber

1961 ◽  
Vol 28 (3) ◽  
pp. 330-334 ◽  
Author(s):  
Eugene Sevin
Keyword(s):  
Energy Transfer ◽  
Numerical Solution ◽  
Parametric Excitation ◽  
Equations Of Motion ◽  
Vibration Absorber ◽  
Single Cycle ◽  
Linearized System ◽  
Nonlinear Equations Of Motion ◽  
Beam Oscillation ◽  
Energy Interchange

The free motion of an undamped pendulum-type vibration absorber is studied on the basis of approximate nonlinear equations of motion. It is shown that this type of mechanical system exhibits the phenomenon of auto parametric excitation; a type of “instability” which cannot be accounted for on the basis of the linearized system. Complete energy transfer between modes is shown to occur when the beam frequency is twice the simple pendulum frequency. On the basis of a numerical solution, approximately 150 cycles of the beam oscillation take place during a single cycle of energy interchange.

An Analysis of Pipe Flange Connections Using Epoxy Adhesives/Anaerobic Sealant Instead of Gaskets

1995 ◽  
Vol 117 (4) ◽  
pp. 298-304 ◽  
Author(s):  
T. Sawa ◽  
R. Sasaki ◽  
M. Yoneno
Keyword(s):  
Stress Distribution ◽  
Internal Pressure ◽  
Theory Of Elasticity ◽  
Experimental Results ◽  
Clamping Force ◽  
Bonding Force ◽  
Epoxy Adhesives ◽  
Analytical Results ◽  
Sealing Performance ◽  
Circle Diameter

This paper deals with the strength and the sealing performance of pipe flange connections combining the bonding force of adhesives with the clamping force of bolts. The epoxy adhesives or anaerobic sealants are bonded at the interface partially instead of gaskets in pipe flange connections. The stress distribution in the epoxy adhesives (anaerobic sealant), which governs the sealing performance, and the variations in axial bolt force are analyzed, using an axisymmetrical theory of elasticity, when an internal pressure is applied to a connection in which two pipe flanges are clamped together by bolts and nuts with an initial clamping force after being joined by epoxy adhesives or anaerobic sealant. In addition, a method for estimating the strength of the combination connection is demonstrated. Experiments are performed and the analytical results are consistent with the experimental results concerning the variation in axial bolt force and the strength of combination connections. It can be seen that the strength of connections increases with a decrease in the bolt pitch circle diameter. Furthermore, it is seen that the sealing performance of such combination connections in which the interface is bonded partially is improved over that of pipe flange connections with metallic gaskets.

scholarly journals Modeling of microwave applicators with an excitation through the wave guide using TLM method

2005 ◽  
Vol 2 (2) ◽  
pp. 137-146
Author(s):  
Tijana Randjelovic ◽  
Jugoslav Jokovic ◽  
Bratislav Milovanovic
Keyword(s):  
Experimental Results ◽  
Wave Guide ◽  
Analytical Results ◽  
Resonant Modes ◽  
Impulse Excitation ◽  
Wave Guides ◽  
Tlm Method ◽  
Microwave Applicator ◽  
Good Agreement ◽  
Microwave Applicators

In this paper, a real microwave applicator with a wave guide used to launch the energy from the source into the cavity is analyzed using 3D TLM method. In order to investigate the influence of the positions and number of feed wave guides to the number of the resonant modes inside the cavity, obtained results are compared with analytical results and results obtained by using TLM software with an impulse excitation as well. TLM method is applied to the both empty and loaded rectangular metallic cavity, and a very good agreement between simulated and experimental results is achieved.

Determination of Stability Derivatives by Impulse-Response Techniques

1977 ◽  
Vol 14 (02) ◽  
pp. 265-275
Author(s):  
Carl A. Scragg
Keyword(s):  
Memory Effect ◽  
Impulse Response ◽  
Traditional Method ◽  
Equations Of Motion ◽  
Experimental Results ◽  
Regular Motion ◽  
Stability Derivatives ◽  
The Stability ◽  
Derivatives Of

This paper presents a new method of experimentally determining the stability derivatives of a ship. Using a linearized set of the equations of motion which allows for the presence of a memory effect, the response of the ship to impulsive motions is examined. This new technique is compared with the traditional method of regular-motion tests and experimental results are presented for both methods.

Implementation of the Wideband Autoparametric Vibration Absorber on a Flexible Structure

2003 ◽  
Author(s):  
Ashwin Vyas ◽  
Anil K. Bajaj ◽  
Arvind Raman
Keyword(s):  
Slow Rate ◽  
Excitation Frequency ◽  
Response Amplitude ◽  
Control Signal ◽  
Experimental Results ◽  
The Other ◽  
Flexible Structure ◽  
Vibration Absorber ◽  
Governing Equations ◽  
Near Resonance

The dynamics of a resonantly excited thin cantilever with an active controller are investigated experimentally. The controller mimics a passive wideband absorber discussed in [1]. PZT patches are bonded to both sides of the beam to actuate it, while an electromagnetic shaker drives the beam near resonance. An active controller consisting of an array of uncoupled controllers is developed, such that the governing equations for the controller are quadratically coupled to the resonating system. The control signal, in terms of the motion of the controllers, is quadratically nonlinear. The controller is implemented using a modelling software and a controller hardware board. Two sets of experiments are performed: one with a constant excitation frequency and the other with a linearly varying excitation frequency at a slow rate (non-stationary excitation). The experimental results verify the analysis presented for the passive wideband autoparametric vibration absorber. They also demonstrate the effectiveness of the absorber in reducing the response amplitude of structures, and its robustness to frequency mistuning.

Designs for an adaptive tuned vibration absorber with variable shape stiffness element

2005 ◽  
Vol 461 (2064) ◽  
pp. 3955-3976 ◽  
Author(s):  
Philip Bonello ◽  
Michael J Brennan ◽  
Stephen J Elliott ◽  
Julian F.V Vincent ◽  
George Jeronimidis
Keyword(s):  
Vibration Control ◽  
Shape Change ◽  
Excitation Frequency ◽  
Variable Stiffness ◽  
Experimental Results ◽  
Vibration Absorber ◽  
Time Varying ◽  
Variable Geometry ◽  
Curved Beams ◽  
Tuned Vibration Absorber

An adaptive tuned vibration absorber (ATVA) with a smart variable stiffness element is capable of retuning itself in response to a time-varying excitation frequency, enabling effective vibration control over a range of frequencies. This paper discusses novel methods of achieving variable stiffness in an ATVA by changing shape, as inspired by biological paradigms. It is shown that considerable variation in the tuned frequency can be achieved by actuating a shape change, provided that this is within the limits of the actuator. A feasible design for such an ATVA is one in which the device offers low resistance to the required shape change actuation while not being restricted to low values of the effective stiffness of the vibration absorber. Three such original designs are identified: (i) A pinned–pinned arch beam with fixed profile of slight curvature and variable preload through an adjustable natural curvature; (ii) a vibration absorber with a stiffness element formed from parallel curved beams of adjustable curvature vibrating longitudinally; (iii) a vibration absorber with a variable geometry linkage as stiffness element. The experimental results from demonstrators based on two of these designs show good correlation with the theory.

Direct Linearization of Continuous and Hybrid Dynamical Systems

2009 ◽  
Vol 4 (3) ◽  
Author(s):  
Julie J. Parish ◽  
John E. Hurtado ◽  
Andrew J. Sinclair
Keyword(s):  
Dynamical Systems ◽  
Nonlinear Equations ◽  
Equilibrium Configuration ◽  
Equations Of Motion ◽  
Hybrid Dynamical Systems ◽  
Linearized Equations ◽  
Direct Linearization ◽  
Taylor Series Expansions ◽  
Nonlinear Equations Of Motion ◽  
And Control

Nonlinear equations of motion are often linearized, especially for stability analysis and control design applications. Traditionally, the full nonlinear equations are formed and then linearized about the desired equilibrium configuration using methods such as Taylor series expansions. However, it has been shown that the quadratic form of the Lagrangian function can be used to directly linearize the equations of motion for discrete dynamical systems. This procedure is extended to directly generate linearized equations of motion for both continuous and hybrid dynamical systems. The results presented require only velocity-level kinematics to form the Lagrangian and find equilibrium configuration(s) for the system. A set of selected partial derivatives of the Lagrangian are then computed and used to directly construct the linearized equations of motion about the equilibrium configuration of interest, without first generating the entire nonlinear equations of motion. Given an equilibrium configuration of interest, the directly constructed linearized equations of motion allow one to bypass first forming the full nonlinear governing equations for the system. Examples are presented to illustrate the method for both continuous and hybrid systems.

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