Theoretical Research of the Active-Type Dynamic Vibration Absorbers

2011 ◽  
Vol 255-260 ◽  
pp. 1820-1824 ◽  
Author(s):  
Zi Li Chen ◽  
Ao Ling Ma ◽  
Xiao Liang You ◽  
Li Qun Shi
Keyword(s):  
Active Control ◽  
Theoretical Research ◽  
Structural Vibration ◽  
Control Force ◽  
Vibration Absorbers ◽  
External Excitation ◽  
Structure Amplitude ◽  
Active Type ◽  
Dynamic Vibration ◽  
Dynamic Vibration Absorbers

Active-type dynamic vibration absorbers (ADVA) is a kind of damping system, installed an actuators in the dynamic vibration absorbers (DVA). According to the actual needs, vibration energy of the structure is transferred to vibration absorbers actively in the process of structural vibration for the effect of external excitation. Therefore, the energy is decayed or transferred quickly and the structural vibration is controlled. If the nature frequency of additional system is the same as external excitation frequency of the original system, actuators doesn’t start and the whole system behaves the property of DVA (passive damping) .Otherwise, actuators starts, which makes the energy of original structure transfer to the vibration absorbers actively, achieving the purpose of energy consumed and vibration reduced. In this paper the concept of ADVA is proposed, and the working principle of ADVA is theoretically analyzed, furthermore the expressions of the system vibration response and active control coefficient are deduced. The curves of active control force and structure amplitude against incentive frequency are plotted respectively by examples.

Parametric Selection of Dynamic Vibration Absorbers for Resonant Suppression of Structure-Absorber Systems

2015 ◽  
Vol 723 ◽  
pp. 31-35
Author(s):  
Lin Liu ◽  
Huang Cheng Fang
Keyword(s):  
Frequency Tuning ◽  
Damping Ratio ◽  
Structural Vibration ◽  
Vibration Absorbers ◽  
Practical Applications ◽  
Dynamic Vibration ◽  
Magnification Factors ◽  
Modal Damping ◽  
Dynamic Vibration Absorbers ◽  
Selection Of

The selection of absorber parameters is of utmost significance for structural vibration control by dynamic vibration absorbers. Based on the classical frequency tuning approach by Den Hartog, optimal damping ratio is derived in close form by equating the dynamic magnification factors of the structural motion at three particular frequencies of interest. In addition, by maximizing the two identical modal damping ratios through root locus in the first quadrant of complex plane, the corresponding absorber damping ratio is derived and proposed as the upper bound of the absorber damping ratio for practical applications.

Suppression of Internal Resonances of Rubber Isolators Using Dynamic Vibration Absorbers

2005 ◽  
Author(s):  
Yu Du ◽  
Efstratios Nikolaidis ◽  
Ricardo A. Burdisso
Keyword(s):  
Experimental System ◽  
Control Force ◽  
Vibration Absorbers ◽  
Internal Resonances ◽  
Low Frequencies ◽  
Dynamic Vibration ◽  
Vibration Model ◽  
Dynamic Vibration Absorbers ◽  
Force Transmissibility ◽  
Three Degree Of Freedom

This paper presents methods to improve the performance of rubber isolators by controlling their Internal Resonances (IRs). IRs are associated with isolators’ internal elastic motions that are due to their inertia. It is well known that IRs degrade the isolator performance as predicted by ideal massless isolator models. However, to the best of the authors’ knowledge, there are no reported works on the suppression of such IRs to improve the isolator performance. This paper proposes two novel approaches to suppress IRs. The first approach uses passive dynamic vibration absorbers (PDVA’s) directly embedded into the isolator. The effectiveness of this approach is investigated analytically using a three degree-of-freedom vibration model. It is shown that the PDVA’s are very effective in attenuating the IRs and improve the isolator’s performance at high frequencies. However, the PDVA’s are ineffective at low frequencies. To overcome this limitation, an active control force is added between the DVA masses, forming the hybrid DVA (HDVA) approach. The effectiveness of both the PDVA and the HDVA approaches is demonstrated experimentally. It is shown that, compared to the original isolator, in the isolation region of the experimental system, adding PDVA’s reduces the force transmissibility by 18.5% and the overall noise radiated by the foundation by 4.3 dB. Furthermore, the HDVA approach reduces the force transmissibility and radiated noise by 92.2% and 9.1 dB, respectively.

Structural Optimization of Cantilever Mechanical Elements

1986 ◽  
Vol 108 (4) ◽  
pp. 427-433 ◽  
Author(s):  
Eugene I. Rivin
Keyword(s):  
Structural Optimization ◽  
Natural Frequencies ◽  
Superior Performance ◽  
Vibration Absorbers ◽  
Stability Margins ◽  
Dynamic Vibration ◽  
Robot Arms ◽  
Limited Effectiveness ◽  
Mass Ratios ◽  
Dynamic Vibration Absorbers

Naturally limited stiffness of cantilever elements due to lack of constraint from other structural components, together with low structural damping, causes intensive and slow-decaying transient vibrations as well as low stability margins for self-excited vibrations. In cases of dimensional limitations (e.g., boring bars), such common antivibration means as dynamic vibration absorbers have limited effectiveness due to low mass ratios. This paper describes novel concepts of structural optimization of cantilever components by using combinations of rigid and light materials for their design. Two examples are given: tool holders (boring bars) and robot arms. Optimized boring bars demonstrate substantially increased natural frequencies, together with the possibility of greatly enhanced mass ratios for dynamic vibration absorbers. Machining tests with combination boring bars have been performed in comparison with conventional boring bars showing superior performance of the former. Computer optimization of combination-type robot arms has shown a potential of 10–60 percent reduction in tip-of-arm deflection, together with a commensurate reduction of driving torque for a given acceleration, and a higher natural frequencies (i.e., shorter transients). Optimization has been performed for various ratios of bending and joint compliance and various payloads.

Dynamic Vibration Absorber Optimal Design With Emphasis on Complete Machine Dynamics Modelling

2008 ◽  
Author(s):  
Bohdan M. Diveyev ◽  
Zinovij A. Stotsko
Keyword(s):  
Optimal Design ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Rotating Machines ◽  
Dynamic Vibration Absorber ◽  
New Methods ◽  
Dynamic Vibration ◽  
Methods Development ◽  
Dynamic Vibration Absorbers ◽  
Dynamics Modelling

The main aim of this paper is improved dynamic vibration absorbers design with taking into account complex rotating machines dynamic The is considered for the complex vibroexitated constructions. Methods of decomposition and the numerical schemes synthesis are considered on the basis of new methods of modal methods. Development of of complicated machines and buildings in view of their interaction with system of dynamic vibration absorbers is under discussion.

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