Vibration-reduction optimization of the point-supporting floating-slab track based on local resonance mechanism

2021 ◽  
pp. 107754632110598
Author(s):  
Hao Jin ◽  
Hongying Wang ◽  
Zheng Li ◽  
Xin Zhou
Keyword(s):  
Band Gap ◽  
Vibration Reduction ◽  
Dynamic Test ◽  
Vertical Vibration ◽  
Resonance Theory ◽  
Support Structure ◽  
Continuous Increase ◽  
Local Resonance ◽  
Slab Track ◽  
Point Support

With the continuous increase of subway operating mileage, the problem of subway vibration has become more and more significant. Nowadays, the point-supported floating-slab track is recognized as the best method to control track vibration, which is mainly designed based on the mass-spring-damping theory. How to further improve the vibration control ability of the point-supported floating-slab track? In this paper, a new type of rubber point-supported floating slab track is designed based on the local resonance theory. Through calculation and dynamic test, it is obtained as follows: (1) The band gap of the point support structure by local resonance type depends on the two vertical vibration modes. (2) As the elastic modulus of the cladding layer increases, the bandwidth of the band gap of the corresponding structure increases significantly. (3) The increase of the vibrator density can increase the bandwidth, while reducing the start and stop frequencies, which is beneficial to attenuate the resonance of the floating-slab track. (4) The cushion material parameters of point support structure by local resonance type 2 will not affect the band gap. The increase in sleeve density will reduce the band gap, which is not conducive to vibration reduction. Local resonance type floating-slab track will be the development direction of track vibration-reduction measures in the future.

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.

Theoretical and Experimental Study of Locally Resonant and Bragg Band Gaps in Flexural Beams Carrying Periodic Arrays of Beam-Like Resonators

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Yong Xiao ◽  
Jihong Wen ◽  
Gang Wang ◽  
Xisen Wen
Keyword(s):  
Band Gap ◽  
Coupling Effect ◽  
Numerical Study ◽  
Spectral Element ◽  
Band Gaps ◽  
Local Resonance ◽  
Periodic Arrays ◽  
Finite Structures ◽  
Resonance Frequencies ◽  
Vibration Transmittance

In this paper, we present a design of locally resonant (LR) beams using periodic arrays of beam-like resonators (or beam-like vibration absorbers) attached to a thin homogeneous beam. The main purpose of this work is twofold: (i) providing a theoretical characterization of the proposed LR beams, including the band gap behavior of infinite systems and the vibration transmittance of finite structures, and (ii) providing experimental evidence of the associated band gap properties, especially the coexistence of LR and Bragg band gaps, and their evolution with tuned local resonance. For the first purpose, an analytical method based on the spectral element formulations is presented, and then an in-depth numerical study is performed to examine the band gap effects. In particular, explicit formulas are provided to enable an exact calculation of band gaps and an approximate prediction of band gap edges. For the second purpose, we fabricate several LR beam specimens by mounting 16 equally spaced resonators onto a free-free host beam. These specimens use the same host beam, but the resonance frequencies of the resonators on each beam are different. We further measure the vibration transmittances of these specimens, which give evidence of three interesting band gap phenomena: (i) transition between LR and Bragg band gaps; (ii) near-coupling effect of the local resonance and Bragg scattering; and (iii) resonance frequency of local resonators outside of the LR band gap.

Influence Analysis of Cell Plate Length to Slab Track Vertical Dynamic Response

2014 ◽  
Vol 505-506 ◽  
pp. 58-63
Author(s):  
Xiao Chuan Ma ◽  
Wei Luo ◽  
Ping Wang ◽  
Bao Ru Guo
Keyword(s):  
Dynamic Response ◽  
Base Plate ◽  
Shell Element ◽  
Cell Plate ◽  
Vertical Vibration ◽  
Vibration Acceleration ◽  
Vibration Displacement ◽  
Coupling Vibration ◽  
Slab Track ◽  
Plate Length

A vehicle-track-subgrade coupling vibration system model was proposed to analysis the influence of cell plate length to slab track vertical dynamic response. The model was built with finite element method, rail was modeled as space beam element, both track plate and base plate were modeled as shell element, the vertical connections between rail, slab and subgrade were modeled as spring-damper element. The results show that with the cell plate length increases, the vertical vibration displacement of rail, track plate and base plate have decreasing tendency; the vertical vibration acceleration of rail has increasing tendency; the vertical vibration acceleration of track plate and base plate have decreasing tendency.

Research on local resonance and Bragg scattering coexistence in phononic crystal

2017 ◽  
Vol 31 (11) ◽  
pp. 1750127 ◽  
Author(s):  
Yake Dong ◽  
Hong Yao ◽  
Jun Du ◽  
Jingbo Zhao ◽  
Jiulong Jiang
Keyword(s):  
Band Gap ◽  
Mass Density ◽  
Resonance Effect ◽  
Phononic Crystal ◽  
Broad Band ◽  
Low Frequency ◽  
Bragg Scattering ◽  
Low Frequencies ◽  
Local Resonance ◽  
Resonance Band

Based on the finite element method (FEM), characteristics of the local resonance band gap and the Bragg scattering band gap of two periodically-distributed vibrator structures are studied. Conditions of original anti-resonance generation are theoretically derived. The original anti-resonance effect leads to localization of vibration. Factors which influence original anti-resonance band gap are analyzed. The band gap width and the mass ratio between two vibrators are closely correlated to each other. Results show that the original anti-resonance band gap has few influencing factors. In the locally resonant structure, the Bragg scattering band gap is found. The mass density of the elastic medium and the elasticity modulus have an important impact on the Bragg band gap. The coexistence of the two mechanisms makes the band gap larger. The band gap covered 90% of the low frequencies below 2000 Hz. All in all, the research could provide references for studying the low-frequency and broad band gap of phononic crystal.

scholarly journals Dynamic modeling and analysis of vertical vibration reduction system for passenger train

Mechanika ◽  
2021 ◽  
Vol 27 (5) ◽  
pp. 415-420
Author(s):  
Shichang Dong ◽  
Hao Song ◽  
Caiyun Song
Keyword(s):  
Dynamical Behavior ◽  
Vibration Reduction ◽  
Vertical Vibration ◽  
The Body ◽  
Degree Of Freedom ◽  
Modeling And Analysis ◽  
Impact System ◽  
Reduction System ◽  
Train Operation ◽  
The Stability

Based on wheel-rail impact vibration and considering the body stiffness and natural damping, this paper builds a four-degree-of-freedom vibro-impact system model for passenger train’s vertical vibration reduction system. The Poincaré map of the system is determined by the analytic solution of the system derived from the motion differential equation of the multi-degree-of-freedom vibro-impact system combined with Newton's second law. It is found that the fork bifurcation, Hopf bifurcation and other dynamical behavior leading to Chaos when the system parameters are changed. On this basis, the dynamic parameters of the train are optimized to avoid chaos in the train operation, reduce the vertical vibration of the train, improve the stability and comfort of the train operation, and provide the theoretical basis for the active vibration reduction design of the train.

scholarly journals Evaluation Method of the Vibration Reduction Effect Considering the Real Load- and Frequency-Dependent Stiffness of Slab-Track Mats

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 452
Author(s):  
Zeming Zhao ◽  
Kai Wei ◽  
Wenhao Ding ◽  
Fang Cheng ◽  
Ping Wang
Keyword(s):  
Frequency Dependence ◽  
Insertion Loss ◽  
Vibration Isolation ◽  
Evaluation Method ◽  
Vibration Reduction ◽  
Frequency Dependent ◽  
Tangent Stiffness ◽  
Slab Track ◽  
Secant Stiffness ◽  
Reduction Effect

The purpose of this research was to investigate and improve the accuracy of the existing slab-track mat (STM) specifications in the evaluation of the vibration reduction effect. The static nonlinearity and dynamic mechanical characteristics of three types of STMs were tested, and then a modified fractional derivative Poynting–Thomson (FDPT) model was used to characterize the preload and frequency dependence. A modified vehicle–floating slab track (FST) coupled dynamic model was established to analyze the actual insertion loss. The insertion loss error evaluated by the frequency-dependent tangent stiffness increased with the increase in STM nonlinearity, and the error obtained by the third preload tangent stiffness was usually greater than that of the second preload. Compared with the secant stiffness, the second preload frequency-dependent tangent stiffness was more suitable for evaluating STMs with high-static–low-dynamics (HSLD) stiffness. In order to reflect the frequency dependence effect and facilitate engineering applications, it is recommended that second preload tangent stiffness corresponding to the natural frequency of the FST be used for evaluation. Furthermore, the insertion loss of the STMs with monotonically increased stiffness decreased as the axle load increased, and the opposite was true for the STMs with monotonically decreased stiffness. The vibration isolation efficiency of the STMs with HSLD stiffness was both stable and better than that of the STMs with monotonic stiffness.

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