Fluidic Composite Tuned Vibration Absorbers

2009 ◽  
Author(s):  
Amir Lotfi-Gaskarimahalle ◽  
Lloyd H. Scarborough ◽  
Christopher D. Rahn ◽  
Edward C. Smith
Keyword(s):  
Forced Vibration ◽  
Axial Strain ◽  
Flow Coefficient ◽  
Resonant Peak ◽  
Matrix Composites ◽  
Mass System ◽  
Isolation Frequency ◽  
Primary Mass ◽  
Tuned Vibration Absorbers ◽  
Internal Volume

This paper presents a novel Tuned Vibration Absorber (TVA) using Fluidic Flexible Matrix Composites (F2MC). Fiber reinforcement of the F2MC tube kinematically links the internal volume with axial strain. Coupling of a fluid-filled F2MC tube through a fluid port to a pressurized air accumulator can suppress primary mass forced vibration at the tuned absorber frequency. 3-D elasticity model for the tube and a lumped fluid mass develops a 4th-order model of an F2MC-mass system. The model provides a closed form isolation frequency that depends mainly on the port inertance, orifice flow coefficient, and the tube parameters. A small amount of viscous damping in the orifice increases the isolation bandwidth. With a fully closed orifice, the zero disappears and the system has a single resonant peak. Variations in the primary mass do not change the isolation frequency, making the F2MC TVA robust to mass variations. Experimental results validate the theoretical predictions in showing a tunable isolation frequency that is insensitive to primary mass variations, and a 94% reduction in forced vibration response relative to the closed-valve case.

Switched Stiffness Vibration Controllers for Fluidic Flexible Matrix Composites

2009 ◽  
Author(s):  
Amir Lotfi-Gaskarimahalle ◽  
Christopher D. Rahn
Keyword(s):  
Equations Of Motion ◽  
Active Vibration Control ◽  
Flexible Structures ◽  
Variable Stiffness ◽  
Flow Coefficient ◽  
Step Response ◽  
Semiactive Control ◽  
Matrix Composites ◽  
Mass System ◽  
3D Elasticity

This paper investigates semi-active vibration control using Fluidic Flexible Matrix Composites (F2MC) as variable stiffness components of flexible structures. 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 changes the internal volume when externally loaded. With an open valve, the fluid in the tube is free to move in or out of the tube, so the stiffness is low. When the valve is closed, the high bulk modulus fluid resists volume change and produces high stiffness. The equations of motion of an F2MC-mass system is derived using a 3D elasticity model and the energy method. The stability of the unforced dynamic system is proven using a Lyapunov approach. To capture the important system parameters, nondimensional full order and reduced order models are developed. A Zero Vibration (ZV) state switch technique is introduced that suppresses vibration in finite time, and is compared to conventional Skyhook semiactive control. The ITAE performance of the controllers is optimized by adjusting the open valve flow coefficient. Simulation results show that the optimal ZV controller outperforms the optimal Skyhook controller by 13% and 60% for impulse and step response, respectively.

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.

Elastothermodynamic Damping of Fiber-Reinforced Metal-Matrix Composites

1995 ◽  
Vol 62 (2) ◽  
pp. 441-449 ◽  
Author(s):  
K. B. Milligan ◽  
V. K. Kinra
Keyword(s):  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Axial Strain ◽  
Second Law Of Thermodynamics ◽  
Infinite Matrix ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Continuous Fiber ◽  
Finite Matrix ◽  
Starting Point

Recently, taking the second law of thermodynamics as a starting point, a theoretical framework for an exact calculation of the elastothermodynamic damping in metal-matrix composites has been presented by the authors (Kinra and Milligan, 1994; Milligan and Kinra, 1993). Using this work as a foundation, we solve two canonical boundary value problems concerning elastothermodynamic damping in continuous-fiber-reinforced metal-matrix composites: (1) a fiber in an infinite matrix, and (2) using the general methodology given by Bishop and Kinra (1993), a fiber in a finite matrix. In both cases the solutions were obtained for the following loading conditions: (1) uniform radial stress and (2) uniform axial strain.

Fluidic Flexible Matrix Composite Vibration Absorber for a Cantilever Beam

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Bin Zhu ◽  
Christopher D. Rahn ◽  
Charles E. Bakis
Keyword(s):  
Cantilever Beam ◽  
Matrix Composite ◽  
Volume Change ◽  
Experimental Testing ◽  
Axial Strain ◽  
Flexible Structures ◽  
Resonant Peak ◽  
Track Length ◽  
Vibration Absorber ◽  
Flexible Matrix Composite

Fluidic flexible matrix composite (F2MC) tubes with resonant fluidic circuits can absorb vibration at a specific frequency when bonded to flexible structures. The transverse structural vibration applies cyclic axial strain to the F2MC tubes. The anisotropic elastic properties of the composite tube amplify the axial strain to produce large internal volume change. The volume change forces fluid through a flow port and into an external accumulator. The fluid inertance in the flow port (inertia track) and the stiffness of the accumulator are analogous to the vibration absorbing mass and stiffness in a conventional tuned vibration absorber. An analytical model of an F2MC-integrated cantilever beam is developed based on Euler–Bernoulli beam theory and Lekhnitskii's solution for anisotropic layered tubes. The collocated tip force to tip displacement analytical transfer function of the coupled system is derived. Experimental testing is conducted on a laboratory-scale F2MC beam structure that uses miniature tubes and fluidic components. The resonant peak becomes an absorber notch in the frequency response function (FRF) if the inertia track length is properly tuned. Tuning the fluid bulk modulus and total flow resistance in the theoretical model produces results that match the experiment well, predicting a magnitude reduction of 35 dB at the first resonance using an F2MC absorber. Based on the experimentally validated model, analysis results show that the cantilever beam vibration can be reduced by more than 99% with optimally designed tube attachment points and flow port geometry.

The Tuned and Damped Gyrostatic Vibration Absorber

1947 ◽  
Vol 157 (1) ◽  
pp. 1-19 ◽  
Author(s):  
R. N. Arnold
Keyword(s):  
Theoretical Prediction ◽  
Torsional Vibration ◽  
Forced Vibration ◽  
Theoretical Study ◽  
Experimental Investigations ◽  
Vibration Absorber ◽  
Viscous Damping ◽  
Mean Velocity ◽  
Mass System ◽  
Low Frequencies

The vibration absorber described in this paper consists of a gyrostat suspended symmetrically about an axis perpendicular to that of the torsional vibration which it is desired to suppress. The gyrostat is fitted with springs and a viscous damping mechanism which allow limited vibration about its axis. This device is a modification of that employed by Schlick (1904)†, in his attempt to stabilize the rolling of ships at sea. The new arrangement, however, is more efficient, is not restricted to very low frequencies, and is, in general, capable of application to vibration superposed on a mean velocity. A theoretical study is made of the response of such an absorber to one- and two-mass vibratory systems under both forced and self-induced vibration, and design methods are derived by which the essential dimensions for any given application may be readily determined. Experimental investigations with a gyrostatic absorber applied to a one-mass system under forced vibration are recorded, and the results compared with theoretical prediction. The design of a full-scale absorber built to suppress vibration of the table of a heavy planing machine is also given, together with the results obtained with the apparatus on trial.

The Numerical and Experimental Investigation Into Hydraulic Characteristics of a No-Load Running Check Valve due to Fluid-Structure Interaction

2018 ◽  
Author(s):  
Xiang-yuan Zhang ◽  
Zhi-jun Shuai ◽  
Chen-xing Jiang ◽  
Wan-you Li ◽  
Jie Jian
Keyword(s):  
Flow Rate ◽  
Ambient Pressure ◽  
Check Valve ◽  
Operating Conditions ◽  
Flow Coefficient ◽  
Pipeline System ◽  
Piping System ◽  
Hydraulic Characteristics ◽  
Mass System ◽  
Excited Vibration

Valve is a very important unit in pipeline system. The valve flow fluctuation brings about structural vibration and unpopular noise, and even leads to the safety problems and disasters. In this paper, a special no-load running check valve is investigated. The check valve is structural complex with one inlet and two outlets. It can be simplified as a spring-mass system which manipulates the flow rate by combine action of the ambient pressure of medium and the spring deformation. The three-dimensional model of the valve is established and also the relationship between pressure drops and flow rate of the valve is obtained in various openings and operating conditions. The structure modals were verified by the field tests and thus its fixing boundaries are obtained correctly. The mechanism causing self-excited vibration of a piping system is determined using a dynamic model which couples the hydraulics of internal flow with the structural motion of a three-ports passive check valve. The coupling is obtained by making the fluid flow coefficient at the check valve to be a function of valve plug displacement. The results are compared with the experimental data, which verifies the correctness of the theoretical results. It is shown that the special valve has its own hydraulic characteristics, which greatly influence its flow distribution as it has two outlets. It was also testified that the coupling between fluid and structure changes its natural frequencies and has a non-negligible impact on the pressure fluctuation while working.

scholarly journals Localization in Multiple Nearly-Identical Tuned Vibration Absorbers

2013 ◽  
Vol 2 (3) ◽  
pp. 157 ◽  
Author(s):  
Abdullah Saleh Alsuwaiyan
Keyword(s):  
Mathematical Model ◽  
Steady State ◽  
Torsional Vibration ◽  
Forced Vibration ◽  
Absolute Magnitude ◽  
Vibration Absorbers ◽  
Steady State Analysis ◽  
Tuned Vibration Absorbers ◽  
Translational Vibration ◽  
The Mathematical Model

The forced vibration of multiple nearly identical translational vibration absorbers is considered. Localization, where the amplitudes of vibration of a group of the absorbers can become relatively large as compared to those of the corresponding perfectly tuned system is investigated. In this work, imperfections amoung the absorbers are allowed and brought into the analysis through the stiffnesses of the absorbers' springs. Steady-state analysis of the mathematical model is used to obtain the results. Results, which focus on translational absorber systems, are found to be consistent with previous results obtained for torsional vibration absorbers. It is found that strengths of the localized responses depend on the levels of imperfections, the relative imperfections among absorbers, and the absorbers' damping. Localization is shown to exist in the undamped multiple nearly-identical vibration absorbers system, or more generally, in the system where the ratio of the level of absorbers' damping to the level of imperfections in the absorbers is small. It is also shown that localized responses can be effectively avoided by introducing some intentional mistuning in the absorbers' stiffnesses. This mistuning should be small in absolute magnitude in order not to reduce the absorbers' performance and should be large when compared to the absorbers' imperfections.

Sign in / Sign up

Export Citation Format

Share Document