scholarly journals Optimisation of absorber parameters in the case of stochastic vibrations in a bridge with a deck platform for servicing pipelines

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jacek Grosel ◽  
Monika Podwórna
Keyword(s):  
Random Vibration ◽  
Random Sequence ◽  
Degree Of Freedom ◽  
Vibration Absorber ◽  
Structure Model ◽  
Optimal Parameters ◽  
Dynamic Vibration Absorber ◽  
Single Degree Of Freedom ◽  
Beam Bridge ◽  
Stochastic Properties

Abstract The paper focuses on the problem of optimising the cooperation between a dynamic vibration absorber (DVA) and a structure. The authors analyse a road beam bridge equipped with a working platform (deck) used to service pipelines installed on the structure. The paper studies the problem of choosing the optimal parameters for damping absorbers that reduce the random vibration of a beam subjected to a random sequence of moving forces with a constant velocity. The stochastic properties of the load are modelled by means of a filtering Poisson process. A single-degree-of-freedom (SDOF) absorber model with a multi-degree-of-freedom (MDOF) primary structure model are is considered.

Suppressing Random Response of a Regular Structure by an Inerter-Based Dynamic Vibration Absorber

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Xiaoling Jin ◽  
M. Z. Q. Chen ◽  
Zhilong Huang
Keyword(s):  
Kinetic Energy ◽  
Random Vibration ◽  
Optimal Location ◽  
Vibration Absorber ◽  
Optimal Parameters ◽  
Dynamic Vibration Absorber ◽  
Dynamic Vibration ◽  
Straight Beam ◽  
The Mean ◽  
Mean Kinetic Energy

This paper concentrates on the random vibration suppression of a regular straight beam by using an inerter-based dynamic vibration absorber. For a wideband random point-driven straight beam with an inerter-based dynamic vibration absorber, the distribution of mean-square velocity response along the axis of the straight beam as well as the mean kinetic energy of the whole beam are first analytically derived through the classical linear random vibration theory. Two optimization objectives are established to determine the optimal design parameters: (1) minimizing the maximal mean-square velocity along the axis of the straight beam, which corresponds to the maximal mean kinetic energy density along the axis and (2) minimizing the mean kinetic energy of the whole beam. Numerical search gives the optimal location and the associated optimal parameters of the inerter-based dynamic vibration absorber. Numerical results for a simply supported straight beam illustrate the better performance of an inerter-based dynamic vibration absorber than a traditional dynamic vibration absorber. Parametric sensitivity studies for the robustness analysis of the beam response to deviations from the optimal parameters are conducted. The optimal location locates on the force-excited point, while the suboptimal location locates on its symmetry position. Furthermore, the optimal and suboptimal locations remain invariable regardless of the upper cutoff frequency of band-limited noise, which is fairly important to the location optimization of the inerter-based dynamic vibration absorber.

Single-Degree-of-Freedom Dynamic Vibration Absorber for Unknown System

2018 ◽  
Author(s):  
Zhang Pandeng ◽  
Liu Zhao ◽  
Zhang Tianfei ◽  
Zhu Yutian ◽  
Zheng Changlong ◽  
...  
Keyword(s):  
Degree Of Freedom ◽  
Vibration Absorber ◽  
Evaluation Function ◽  
Vibration System ◽  
Dynamic Vibration Absorber ◽  
Single Degree Of Freedom ◽  
Technology Application ◽  
Single Degree ◽  
Dynamic Vibration ◽  
Unknown System

Vibration causes problems, and the technology of dynamic vibration absorber is always used to control it. So far, the technology is mature, but based on the known of modes, mass, stiffness, damping and other parameters of the vibration system. For an unknown system or complicated system, how to use this technology is what the paper mainly discusses. The dynamic vibration absorber of this paper is a single-degree-of-freedom, and only one direction is to be controlled. The evaluation function is the ratio between the system vibration response after adding dynamic vibration absorber and the original exciting force, which can reflect the effect of dynamic vibration absorber. After separating the unknown system and the dynamic vibration absorber, based on force analysis, we analyze them separately and deduce the calculating formula of the evaluation function. The order of parameters to be determined is mass, stiffness, and damping. Flow chart is presented on how to use the method. The method is validated by a known system of two degree-of-freedom vibration system. The main innovation of this paper is to propose a method of predicting the effect of adding a single-degree-of-freedom dynamic vibration absorber to an unknown system to control a certain direction. This method doesn’t need to consider the system damping factor. This paper extends the scope of technology application of dynamic vibration absorber.

scholarly journals Study on the Vibration Suppression Method of Urban Railway Vehicles Based on a Composite Dynamic Vibration Absorber

2019 ◽  
Vol 296 ◽  
pp. 01010
Author(s):  
Qian Sun ◽  
Yongpeng Wen ◽  
Yu Zou
Keyword(s):  
Vibration Suppression ◽  
Vibration Reduction ◽  
Low Frequency ◽  
Peak Frequency ◽  
Degree Of Freedom ◽  
Vibration Absorber ◽  
Dynamic Vibration Absorber ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Dynamic Vibration

To reduce the bounce and the pitch vibration of carbody, a vertical dynamic model for urban rail vehicles is established to analyze the vibration response of the carbody in the low frequency range. In this paper, different methods of single-degree-of-freedom dynamic vibration absorber to suppress the vibration for carbody are investigated. The limits of single-degree-of-freedom dynamic vibration absorber to the vibration reduction effect of carbody are pointed out. After that, the design of a composite dynamic vibration absorber including a double oscillator structure is introduced. A vibration discreteness index is used to evaluate dynamic vibration absorbers with various designs for the vibration damping performance. Finally, the vibration reduction performance of the composite dynamic vibration absorber is verified by Sperling’s riding index. The results demonstrate that the performance of the single degree of freedom dynamic vibration absorber attached to a carbody may increase the vibration within a partial scope, when the peak frequency of vibration is far away from the design frequency. The installation of the composite dynamic vibration absorber vibration provides gentler running experience for passengers.

Optimal Parameters and Characteristics of a Three Degree of Freedom Dynamic Vibration Absorber

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Mariano Febbo
Keyword(s):  
Simulated Annealing ◽  
Vibration Reduction ◽  
Observation Point ◽  
Degree Of Freedom ◽  
Vibration Absorber ◽  
Optimal Parameters ◽  
Dynamic Vibration Absorber ◽  
Rotational Mode ◽  
Dynamic Vibration ◽  
Three Degree Of Freedom

The present study is devoted to the determination of the optimal parameters and characteristics of a three degree of freedom dynamic vibration absorber (3 DOF DVA) for the vibration reduction of a plate at a given point. The optimization scheme uses simulated annealing and constrained simulated annealing, which is capable of optimizing systems with a set of constraints. Comparisons between a 3 DOF DVA and multiple (5) 1 DOF DVAs show a better performance of the former for vibration reduction. Regarding the characteristics of the optimal 3 DOF DVA, numerical tests reveal that the absorber is robust under variations of the observation point and for 10% variations of its mass, stiffness and damping. From the analysis of parameter changes of the plate, it is found that the optimal 3 DOF DVA is almost insensitive to a mass change, and sensitive to a change of Young’s modulus for low frequencies. In this case, a decrease in Young’s modulus causes a decrease in its effectiveness, and an increase improves it. The study of the effect of the 3 DOF DVA location on its effectiveness reveals that the requirements of closeness of the absorber to an antinode of the bare primary structure and to the observation point improve its performance. Additionally, for a rotational mode of the 3-DOF DVA about some axis, the effectiveness of the absorber at a given frequency can be notably increased if it is located at a position of the primary system with an in-phase or out-of- phase motion of the attachment points according to the rotational-mode characteristics of the 3-DOF DVA at this frequency.

scholarly journals Study on Multi-Degree of Freedom Dynamic Vibration Absorber of the Carbody of High-Speed Trains

2021 ◽  
Author(s):  
Yu SUN ◽  
Jinsong Zhou ◽  
Dao Gong ◽  
Yuanjin Ji
Keyword(s):  
Vibration Control ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Dynamic Stiffness ◽  
Degree Of Freedom ◽  
Vibration Absorber ◽  
High Speed Train ◽  
Dynamic Vibration Absorber ◽  
Multiple Degrees Of Freedom ◽  
Dynamic Vibration

Abstract To absorb the vibration of the carbody of the high-speed train in multiple degrees of freedom, a multi-degree of freedom dynamic vibration absorber (MDOF DVA) is proposed. Installed under the carbody, the natural vibration frequency of the MDOF DVA from each DOF can be designed as a DVA for each single degree of freedom of the carbody. Hence, a 12-DOF model including the main vibration system and a MDOF DVA is established, and the principle of Multi-DOF dynamic vibration absorption is analyzed by combining the design method of single DVA and genetic algorithm. Based on a high-speed train dynamics model including an under-carbody MDOF DVA, the vibration control effect on each DOF of the MDOF DVA is analyzed by the virtual excitation method. Moreover, a high static and low dynamic stiffness (HSLDS) mount is proposed based on a cam–roller–spring mechanism for the installation of the MDOF DVA due to the requirement of the low vertical dynamic stiffness. From the dynamic simulation of a non-linear model in time-domain, the vibration control performance of the MDOF DVA installed with nonlinear HSLDS mount on the carbody is analyzed. The results show that the MDOF DVA can absorb the vibration of the carbody in multiple degrees of freedom effectively, and improve the running ride quality of the vehicle.

Three-Element Vibration Absorber–Inerter for Passive Control of Single-Degree-of-Freedom Structures

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Abdollah Javidialesaadi ◽  
Nicholas E. Wierschem
Keyword(s):  
Passive Control ◽  
Translational Motion ◽  
Tuned Mass Damper ◽  
Degree Of Freedom ◽  
Superior Performance ◽  
Underlying Structure ◽  
Vibration Absorber ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Mass Damper

In this study, a novel passive vibration control device, the three-element vibration absorber–inerter (TEVAI) is proposed. Inerter-based vibration absorbers, which utilize a mass that rotates due to relative translational motion, have recently been developed to take advantage of the potential high inertial mass (inertance) of a relatively small mass in rotation. In this work, a novel configuration of an inerter-based absorber is proposed, and its effectiveness at suppressing the vibration of a single-degree-of-freedom system is investigated. The proposed device is a development of two current passive devices: the tuned-mass-damper–inerter (TMDI), which is an inerter-base tuned mass damper (TMD), and the three-element dynamic vibration absorber (TEVA). Closed-form optimization solutions for this device connected to a single-degree-of-freedom primary structure and loaded with random base excitation are developed and presented. Furthermore, the effectiveness of this novel device, in comparison to the traditional TMD, TEVA, and TMDI, is also investigated. The results of this study demonstrate that the TEVAI possesses superior performance in the reduction of the maximum and root-mean-square (RMS) response of the underlying structure in comparison to the TMD, TEVA, and TMDI.

Extending Den Hartog’s Vibration Absorber Technique to Multi-Degree-of-Freedom Systems

2004 ◽  
Vol 127 (4) ◽  
pp. 341-350 ◽  
Author(s):  
Mehmet Bulent Ozer ◽  
Thomas J. Royston
Keyword(s):  
Matrix Inversion ◽  
Degree Of Freedom ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Single Degree Of Freedom ◽  
Inversion Theorem ◽  
Single Degree ◽  
Main System ◽  
Dynamic Vibration Absorbers ◽  
Invariant Points

The most common method to design tuned dynamic vibration absorbers is still that of Den Hartog, based on the principle of invariant points. However, this method is optimal only when attaching the absorber to a single-degree-of-freedom undamped main system. In the present paper, an extension of the classical Den Hartog approach to a multi-degree-of-freedom undamped main system is presented. The Sherman-Morrison matrix inversion theorem is used to obtain an expression that leads to invariant points for a multi-degree-of-freedom undamped main system. Using this expression, an analytical solution for the optimal damper value of the absorber is derived. Also, the effect of location of the absorber in the multi-degree-of-freedom system and the effect of the absorber on neighboring modes are discussed.

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