scholarly journals Bending Vibration Suppression of a Flexible Multispan Shaft Using Smart Spring Support

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Bo Peng ◽  
Rupeng Zhu ◽  
Miaomiao Li ◽  
Ziyang Tang
Keyword(s):  
Dry Friction ◽  
Vibration Suppression ◽  
Vibration Reduction ◽  
Control Parameters ◽  
Bending Vibration ◽  
Suppression Effect ◽  
Numerical Example ◽  
The Relationship ◽  
Spring Support ◽  
Supercritical Speed

Because the flexible multispan shaft in large machines often rotates at supercritical speed, it is desirable to find ways to suppress the resulting bending vibration. In this paper, a novel type of support structure is proposed and investigated, which can suppress the bending vibration using dry friction. This approach is called Smart Spring support (SMSS). A dynamic model for the multispan shaft with SMSS is developed. The relationship between the vibration suppression effect and the control parameters of the SMSS is obtained through a numerical example involving a helicopter tail drive shaft. A structure of the SMSS is designed and examined with a rotor test. The results demonstrate that the SMSS has a significant effect on bending vibration suppression of flexible multispan shafts. The vibration-reduction ratio of the peak amplitude reaches 57.2% in the numerical example and 45.2% in the rotor test.

scholarly journals Vibration Suppression for Beam-Like Repeating Lattice Structure Based on Equivalent Model by a Nonlinear Energy Sink

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Gen Liu ◽  
Gongfa Chen ◽  
Fangsen Cui
Keyword(s):  
Vibration Suppression ◽  
Lattice Structure ◽  
Vibration Reduction ◽  
Coupled System ◽  
Nonlinear Energy Sink ◽  
Equivalent Model ◽  
External Excitation ◽  
Suppression Effect ◽  
Energy Sink ◽  
Nonlinear Energy

Based on the fully deployed space beam-like truss, the vibration reduction of the lattice structure is studied by using the local NES (nonlinear energy sink) attachment in this paper. The beam-like lattice structure is modeled as an equivalent linear continuous system (a finite length beam) by the equivalent method and validated with the finite element results. The dynamic vibration equations for the equivalent cantilever beam are established and the governing equations for the equivalent beam with NES are approximated by the Galerkin method. The displacement responses of the beam with and without NES attached under shock excitation are obtained. With NES at different positions, the amplitude responses of the coupled system under the external excitation at different positions are calculated to evaluate the suppression effect of the NES attachment to the structure. And with different masses of the NES, the amplitude responses of the coupled structure subject to the external excitation at different positions are also investigated to get the influence of the mass of the NES attachment to the vibration reduction. It can be seen from the results that the NES attachment can attenuate the response of the beam-like truss under transient excitation efficiently. And with the mass of NES attachment increasing, the vibration amplitude of the coupled system declines more rapidly, and the energy consumption efficiency of the NES attachment is higher. Moreover, the attenuation effect of the NES with different masses is experimentally analyzed. The experimental results are in good accord with the theoretical calculation.

Research on Suppressing Vibration of Mistuning Cyclic-Periodic Structure

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Pengcheng Deng ◽  
Lin Li ◽  
Chao Li
Keyword(s):  
Periodic Structure ◽  
Vibration Suppression ◽  
Vibration Reduction ◽  
Element Model ◽  
Lumped Parameter Model ◽  
Modal Assurance Criterion ◽  
Suppression Effect ◽  
Lumped Parameter ◽  
Two Systems ◽  
Aero Engines

Abstract This paper deals with the cyclic-periodic structure with piezoelectric shunt circuits or a parallel piezoelectric network. The objective is to obtain the vibration suppression effect of them on the cylic-periodic structure. The background of the research is about vibration reduction of bladed disks in aero-engines, and the system is simulated by a lumped parameter model. The tuned and mistuned dynamic equations of the system are derived. The method of equivalent blisk model (EBM) is used to identify the lumped parameters of a finite element model, which is related to the experimental model. Then the Modified Modal Assurance Criterion (MMAC) is used to evaluate the vibration suppression ability of shunt circuits and the network. The numerical results show that both of these two systems can control vibration well, even the mechanical and electrical mistuning level are up to 10 %, and there is an optimal resistance which can be used to design the system to get a good performance of vibration suppression. An experiment is performed to validate the analytical results. The experimental results demonstrate that the ability of vibration suppression for both two systems are almost the same, but the piezo-network has an advantage in vibration delocalization of the mistuned system.

Vibration Suppression Effect in a Bending-Levitated Flexible Steel Plate by the Electromagnetic Force

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Hideaki Kato ◽  
Hiroki Marumori ◽  
Hikaru Yonezawa ◽  
Takayoshi Narita
Keyword(s):  
Tilt Angle ◽  
Steel Plate ◽  
Vibration Suppression ◽  
Suppression Effect ◽  
Levitation Performance ◽  
Thin Steel ◽  
Plate Shape ◽  
The Finite Difference Method ◽  
Thin Steel Plate ◽  
The Relationship

We have proposed a method of levitating a thin steel plate by moderately bending it beforehand. To elucidate the bending levitation performance, an ultrathin steel plate was levitated; the relationship among the tilt angle of the electromagnets, the standard deviation of the displacement, and the levitation probability was evaluated. Furthermore, to elucidate the effective tilt angle of the electromagnets for bending, the steel plate shape was analyzed using the finite difference method (FDM). When levitating the thin steel plate at the optimal tilt angle of the electromagnets attained by the FDM, a desirable levitation performance was achieved robustly.

scholarly journals A study on the vibration dissipation mechanism of the rotating blade with dovetail joint

2021 ◽  
pp. 146134842098533
Author(s):  
Chaofeng Li ◽  
Zengchuang Shen ◽  
Zilin Chen ◽  
Houxin She
Keyword(s):  
Dry Friction ◽  
Vibration Reduction ◽  
Friction Model ◽  
Rotating Speed ◽  
System Parameters ◽  
Tangential Stiffness ◽  
Damping Characteristics ◽  
Rotating Blade ◽  
Spatial Beam ◽  
Dissipation Mechanism

The vibration dissipation mechanism of the rotating blade with a dovetail joint is studied in this paper. Dry friction damping plays an indispensable role in the direction of vibration reduction. The vibration level is reduced by consuming the total energy of the turbine blade with the dry friction device on the blade-root in the paper. The mechanism of the vibration reduction is revealed by the variation of the friction force and the energy dissipation ratio of dry friction. In this paper, the flexible blade with a dovetail interface feature is discretized by using the spatial beam element based on the finite element theory. Then the classical Coulomb-spring friction model is introduced to obtain the dry friction model on the contact interfaces of the tenon-mortise structure. What is more, the effects of the system parameters (such as the rotating speed, the friction coefficient, the installation angle of the tenon) and the excitation level on blade damping characteristics are discussed, respectively. The results show that the variation of the system parameters leads to a significant change of damping characteristics of the blade. The variation of the tangential stiffness and the position of the external excitation will affect the nonlinear characteristics and vibration damping characteristics.

Research on Damping Vibration Reduction Design Method of Aeroengine Supporting Structure System

2020 ◽  
Author(s):  
Chao Li ◽  
Binglong Lei ◽  
Yanhong Ma ◽  
Jie Hong
Keyword(s):  
Dry Friction ◽  
Dynamic Stiffness ◽  
Vibration Reduction ◽  
Vibration Response ◽  
Contact Friction ◽  
Friction Damper ◽  
Support Structure ◽  
Response Control ◽  
Structure System ◽  
Supporting Structure

Abstract Typical turbofan engine-support-structure systems having a high thrust-to-weight ratio are light, and the structure primarily comprises a plate and shells. The local vibration response of the support structure is excessively large when different frequency loads are applied. A structural vibration response control method based on dry friction damping is proposed to control the excessive vibration response. A dry friction damper with dynamic suction was designed to enhance the damping characteristics of the rotor supporting structure system in the wide frequency domain, without sacrificing the dynamic stiffness of the structure. The system is designed to effectively control the vibration response of the supporting structure at the working-speed frequency. Through theoretical modeling and simulation analyses, the influence of friction contact and damper structure characteristics on the damping effect is described quantitatively. Furthermore, the design idea and the damping process of the supporting structure are described. The calculation results show that the contact friction of the dry friction damper can consume the vibration energy of the supporting frame. A reasonable design of the contact characteristics and geometric configuration parameters of the damper can further optimize the vibration-reduction effect, and thereby improve the vibration response control design of the supporting structure system of aeroengines.

The Influence of Variable-Speed Waveforms on Vibration Suppression in Time-Varying Speed Cutting

2013 ◽  
Vol 690-693 ◽  
pp. 2514-2518
Author(s):  
Juan Cong ◽  
Yun Wang ◽  
Wei Na Yu
Keyword(s):  
Wave Speed ◽  
Vibration Suppression ◽  
Sine Wave ◽  
Time Varying ◽  
Variable Speed ◽  
Suppression Effect ◽  
Speed Variation ◽  
Input And Output ◽  
System Input ◽  
Better Than

Through the research on the change of system input and output energy in time-varying speed cutting, the influence of variable-speed waveforms on vibration suppression effect in time-varying speed cutting is quantitatively analyzed in this paper. A conclusion can be drawn that sine wave speed variation is better than triangle wave speed variation in vibration suppression.

Experimental Investigation of Dust Amount from Free Falling Particle Stream Effected by Deflector Curvature of Dust Suppression

2013 ◽  
Vol 864-867 ◽  
pp. 1789-1792 ◽  
Author(s):  
Ze Qin Liu ◽  
Zhen Jing Wu ◽  
Ze Peng Feng
Keyword(s):  
Experimental Investigation ◽  
Dust Control ◽  
Emissions Reduction ◽  
Fugitive Dust ◽  
Bulk Materials ◽  
Dust Suppression ◽  
Suppression Effect ◽  
Particle Stream ◽  
Free Falling ◽  
The Relationship

This paper focuses on the study of the curvatures of deflector installed on the below receiving device to effect the dust amount from the free falling particle stream. The deflector curvature was artificially controlled to limit the fugitive dust direction which was generated by the collision between the free falling bulk materials and the receiving device. This method was used to improve efficiency of the dust control system to exhaust fugitive dust, and to achieve the targets of energy conservation and emissions reduction. The experimental method was adopted to explore the relationship between the deflector curvature and the producing dust quantity. The experimental results indicated that, the dust suppression effect containing deflector contained a certain radian was more remarkable, when the height of the free falling of bulk materials was constant. The producing dust quantity decreased slightly with the deflector curvature increasing, and then increased rapidly. When the deflector curvature was 0.045 cm-1 or 0.060cm-1, the minimum of producing dust quantity could be obtained, and the dust removal effect might be significant.

The Fairing Arrangement for Vortex Induced Vibration Suppression Effect in Soliton Current

2020 ◽  
Vol 103 (sp1) ◽  
pp. 293
Author(s):  
Xiaoliang Qi ◽  
Dagang Zhang ◽  
Haiyan Guo ◽  
Youxiao Chen
Keyword(s):  
Vibration Suppression ◽  
Vortex Induced Vibration ◽  
Suppression Effect

scholarly journals Effect of adding mass to rotor on in-plane squeal in automotive disc brake

2018 ◽  
Vol 211 ◽  
pp. 13006
Author(s):  
Takashi Nakae ◽  
Takahiro Ryu ◽  
Hiroki Goto ◽  
Daisuke Sato
Keyword(s):  
Dry Friction ◽  
Coulomb Friction ◽  
Disc Brake ◽  
Vibration Modes ◽  
Concentrated Mass ◽  
Mass Model ◽  
Out Of Plane ◽  
The Relationship

This study experimentally examined disc brake-generated inplane squeal by looking at vibration modes. The in-plane squeal was determined to be closely related to both the out-of-plane squeal that has directionality caused by Coulomb friction and the in-plane squeal caused by dry friction. The characteristics of in-plane squeal were also analytically investigated using a concentrated mass model formed by connected massless beams, and the relationship between mass added to the rotor and squeal suppression was clarified.

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