Vertical vibration modelling and vibration response analysis of Chinese high-speed train passengers at different locations of a high-speed train

Author(s):  
Chun-jun Chen ◽  
Chao Fang ◽  
Guo-qing Qu ◽  
Zhi-ying He

To study the vibration of a passenger's head and internal organs at different locations of a high-speed train, a 9-degrees-of-freedom (DOF) model of seated passengers is proposed in this paper, and its parameters of the damping coefficients and stiffnesses are identified. Next, the response of the head and internal organs is simulated by applying the vibrational stimulation generated by a 27-DOF vehicle model under track irregularity. Moreover, by applying the measured vibration signal, the following conclusions can be drawn: (1) the weakest response is detected at the centre of the compartment of the wagon, and a stronger response is detected at the centre of the bogie, with the rolling motion having a greater effect 1 m away from the centre of the bogie; (2) the response of the human internal organs is stronger than that of the head under stimulation with a lower frequency of less than 3 Hz, and a similar conclusion can be drawn in the range of 5 to 8 Hz. However, if the frequency is in the range between 8 and 15 Hz, the situation is entirely different. The responses of both the head and internal organs are reduced at frequencies over 20 Hz; (3) from the real application, it can be inferred that the greatest response can be detected at approximately 3 Hz for internal organs and at 8 Hz or higher for the head.

IEEE Access ◽  
2018 ◽  
Vol 6 ◽  
pp. 50709-50719 ◽  
Author(s):  
Yumei Liu ◽  
Ningguo Qiao ◽  
Congcong Zhao ◽  
Jiaojiao Zhuang

2021 ◽  
Author(s):  
Yu SUN ◽  
Jinsong Zhou ◽  
Dao Gong ◽  
Yuanjin Ji

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.


Author(s):  
Timothy W. Dimond ◽  
Amir A. Younan ◽  
Paul E. Allaire ◽  
John C. Nicholas

Tilting pad journal bearings (TPJBs) provide radial support for rotors in high-speed machinery. Since the tilting pads cannot support a moment about the pivot, self-excited cross-coupled forces due to fluid-structure interactions are greatly reduced or eliminated. However, the rotation of the tilting pads about the pivots introduces additional degrees of freedom into the system. When the flexibility of the pivot results in pivot stiffness that is comparable to the equivalent stiffness of the oil film, then pad translations as well as pad rotations have to be considered in the overall bearing frequency response. There is significant disagreement in the literature over the nature of the frequency response of TPJBs due to non-synchronous rotor perturbations. In this paper, a bearing model that explicitly considers pad translations and pad rotations is presented. This model is transformed to modal coordinates using state-space analysis to determine the natural frequencies and damping ratios for a four-pad tilting pad bearing. Experimental static and dynamic results were previously reported in the literature for the subject bearing. The bearing characteristics as tested are considered using a thermoelastohydrodynamic (TEHD) model. The subject bearing was reported as having an elliptical bearing bore and varying pad clearances for loaded and unloaded pads during the test. The TEHD analysis assumes a circular bearing bore, so the average bearing clearance was considered. Because of the ellipticity of the bearing bore, each pad has its own effective preload, which was considered in the analysis. The unloaded top pads have a leading edge taper. The loaded bottom pads have finned backs and secondary cooling oil flow. The bearing pad cooling features are considered by modeling equivalent convective coefficients for each pad back. The calculated bearing full stiffness and damping coefficients are also reduced non-synchronously to the eight stiffness and damping coefficients typically used in rotordynamic analyses and are expressed as bearing complex impedances referenced to shaft motion. Results of the modal analysis are compared to a two degree-of-freedom second-order model obtained via a frequency-domain system identification procedure. Theoretical calculations are compared to previously published experimental results for a four-pad tilting pad bearing. Comparisons to the previously published static and dynamic bearing characteristics are considered for model validation. Differences in natural frequencies and damping ratios resulting from the various models are compared, and the implications for rotordynamic analyses are considered.


2012 ◽  
Vol 226-228 ◽  
pp. 102-105
Author(s):  
Wen Qing Zhu ◽  
Yang Yong Zhu

With the rapid development of high-speed railway in China, the aerodynamic brake is very likely to be an important emergency braking mode of high-speed train in the future. This paper takes aerodynamic braking wing as the object, and uses the finite element software to divide the meshes, then analyses the model influenced by static stress. After simulating the vibratory frequency response of the model in the flow field, it finds that the largest deformation happens in the middle of the upper edge of the wind wing, when the wind speed gets to 500km/h and the load frequency to 4Hz. Some conclusions of this thesis can provide reference for researching the applying the aerodynamic brake in the high-speed trains and laying the foundation for solving the riding and braking safety problems.


2019 ◽  
Vol 68 (11) ◽  
pp. 10607-10617 ◽  
Author(s):  
Zhiwei Wang ◽  
Yang Song ◽  
Zhonghui Yin ◽  
Ruichen Wang ◽  
Weihua Zhang

2013 ◽  
Vol 779-780 ◽  
pp. 731-738 ◽  
Author(s):  
Ke Xin Zhang ◽  
Jian Wei Yao ◽  
Ze Ping Zhao

The principal aim of this paper is to determine the reasonable design parameters of high-speed railway vibration attenuation. The orthogonal test method is used to design the test of ground vibration induced by high-speed train. Four main factors that impact the maximum ground vertical vibration level are selected, and different values are given to each factor, so 8 groups of combinations can be obtained by using orthogonal test technique. Each group test data of the maximum ground vertical vibration level can be obtained by conducting vehicle testing on-track. In this paper, the primary and secondary factors that impact the maximum ground vertical vibration level are determined by range analysis. Moreover, the neural network theory is used to establish a model of the ground vertical vibration level, and this model can be trained and verified by the test data. The impact factors can be predicted by the method of combining orthogonal test and neural network concerning the specified vibration limit, and the value of maximum ground vertical vibration level with the predicted factors meets the requirement of accuracy. The conclusions provide a valuable reference to the vibration attenuation design of the high-speed railway.


2011 ◽  
Vol 90-93 ◽  
pp. 2062-2067 ◽  
Author(s):  
Zhan Rui Wu ◽  
Tai Yue Qi ◽  
Lin Zhong

The vibration loads will be produced between wheel and rail on the running of the high-speed Train. The vibration energy will be transferred to the ground formation through the rail, guiding bed and tunnel lining structure, thereby causing vibration between the formation and surface and environmental interference effect problems. Thus the research of related issues caused by the high-speed train vibration has the vital great significance. The train design speed of the Shiziyang shield tunnel for Guangzhou-Shenzhen-Hong Kong passenger dedicated line is up to 350km/h. In this paper the research object is located in the segment of the homogeneous formation of the Shiziyang shield tunnel. The analysis of this paper includes the dynamic response rules of the shield tunnel and formation under the single high-speed train loads and the law of the pore water pressure accumulation and dispersion under train cyclic loading.


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