scholarly journals Dynamic Analysis of Vehicle Track Coupling Based on Double Beam Track Model

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Yayun Qi ◽  
Huanyun Dai ◽  
Jianjin Yang ◽  
Kun Xu
Keyword(s):  
Frequency Band ◽  
High Frequency ◽  
Harmonic Excitation ◽  
Vertical Acceleration ◽  
Beam Model ◽  
Vertical Force ◽  
Nonlinear Method ◽  
Single Beam ◽  
Double Beam ◽  
Random Irregularity

The rail was considered as double Timoshenko beam in this paper, applied to the vehicle track coupling dynamics model; the Hertz nonlinear method is used to calculate the wheel rail contact force. Wheel rail vertical force and response of vehicle are calculated by using the model under random irregularity and single harmonic excitation; at the same time, wheel rail force and vertical acceleration response of 3-order, 10-order, and 19-order wheel polygon were calculated. The results show that, under the excitation of random irregularity, the wheel rail vertical force of two models was very close in the low frequency band, and the response of the double beam model in the high frequency band of 200–1000 Hz is larger than the single beam model, and the acceleration and displacement responses of the double beam model are relatively close. Under a single harmonic excitation, the double beam model has a shorter wheel rail force attenuation time than that of the single beam model. And wheel rail force peak value of double beam model is 9% larger than that of single beam model. Similarly, the vertical displacement of the double beam model increased by 2.6%. Under the 3-order and 10-order wheel polygon excitation, vertical wheel rail peak force of double beam is, respectively, 37.5% and 50% larger than single beam model; the vertical frame acceleration amplitude is 1 g and 1.7 g; under the 19-order polygon wheel excitation, the difference of the wheel rail force between two models is very small, and the amplitude of acceleration of bogie is 2.3 g. And double beam model has more advantage in analyzing high frequency problems such as wheel polygonization.

scholarly journals Transfer Matrix Method for Dynamic Characteristics Analysis of Missile-Canister System in Silo

2020 ◽  
Vol 319 ◽  
pp. 01001
Author(s):  
Anfeng Zhou ◽  
Daokui Li ◽  
Shiming Zhou ◽  
Da Cui ◽  
Xuan Zhou
Keyword(s):  
Transfer Matrix ◽  
Dynamic Characteristics ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Discrete Distribution ◽  
Mode Shapes ◽  
Beam Model ◽  
Radial Vibration ◽  
Single Beam ◽  
Double Beam

In order to ensure the safety of the missile-canister system in silo during the earthquake, a modified transfer matrix method is provided to study the dynamic characteristics of the system. Firstly, a discrete viscoelastic connected double-beam model is developed taking account of the structural nonuniformity and the discrete distribution of the adapters. Secondly, the transfer matrix method of a single beam is modified to solve the problem of discrete connection between the two beams of the double-beam model. Then the natural circular frequencies and mode shapes are calculated by the proposed method, comparing with the finite element method (FEM). Finally, the influence of the stiffness of radial vibration isolators and adapters on the dynamic characteristics of the system is analysed. The comparison shows that the results of the proposed method are well consistent with the FEM calculations and the proposed method is validated. The variations of the first six natural circular frequencies with radial vibration isolator stiffness and adapter stiffness are obtained, which provides a basis for the seismic-relieving design.

Comparative Feature Analysis of Ground Surface Vibration Induced by High-Speed Train Running on Viaduct and Embankment

2014 ◽  
Vol 638-640 ◽  
pp. 1229-1232
Author(s):  
Kun Ming Mao ◽  
Ting Ting Wang ◽  
Qian Wen Ru ◽  
Yan Li
Keyword(s):  
Frequency Band ◽  
High Frequency ◽  
High Speed ◽  
Fourier Spectrum ◽  
Three Dimensional ◽  
Low Frequency ◽  
Ground Surface ◽  
Vertical Acceleration ◽  
High Frequency Band ◽  
Surface Vibration

Based on the Abaqus parallel computing cluster system platform, the three-dimensional finite element model of train-track-viaduct/embankment-foundation-soil coupling is established. The three-dimensional space-time variation and Fourier spectrums characters of ground surface vibration vertical accelerations by high-speed train running on viaduct and embankment are simulated. The result shows that ground surface vibration is mainly excited by periodic axle force of the train in the site near the viaduct pier. In the site far from the viaduct pier, ground surface vibration is mainly from the transmission of the site near the viaduct pier. With the increased distance between the viaduct pier, the peak value of ground surface vibration vertical acceleration decreases, and decreases significantly when the distance is within 10m. There are two main frequency bands of Fourier spectrum of ground surface vibration vertical acceleration: low-frequency band 0-12Hz and high-frequency band 35-47Hz of viaduct route, and low-frequency band 0-21Hz and high-frequency band 25-45Hz of embankment route. In general, with the increased distance between viaduct/embankment, Fourier spectrum amplitude of every frequency band decrease, and attenuation speed of high-frequency band is much faster than-frequency band’s.

Coupled Flexural–Longitudinal Vibrations of Timoshenko Double-Beam Systems Induced by Mass Eccentricities

2016 ◽  
Vol 08 (05) ◽  
pp. 1650067
Author(s):  
Jian Wang ◽  
Zhenguo Zhang ◽  
Hongxing Hua
Keyword(s):  
Natural Frequencies ◽  
Flexural Vibration ◽  
Longitudinal Direction ◽  
Forced Response ◽  
Beam Model ◽  
Vertical Force ◽  
Governing Equations ◽  
Longitudinal Vibrations ◽  
Mass Eccentricity ◽  
Double Beam

In many instances, marine vessel may suffer unexpected flexural–longitudinal vibrations as the consequences of the unevenly distribution of the inner structures and equipment. In order to study the dynamic behaviors of the marine vessel with the involvement of the mass unevenness, the whole vessel is modeled as a discretely connected double-beam system in this paper. In this model, the misalignment between geometric and gravitational center are considered as the simplification of the mass unevenness. The governing equations of coupled flexural–longitudinal vibrations of Timoshenko beam due to mass eccentricity are derived. Extending to the double-beam model, the natural frequencies, modal shapes and forced response of the system are obtained analytically by using the modified transfer matrix method. The comparison between the present method and the conventional finite element method shows a great match. The result indicates that the existence of mass eccentricity can cause significant coupled flexural–longitudinal vibrations, thus, even only vertical force is applied, the vibration in longitudinal direction can be excited and controlled by the natural frequencies of the flexural vibration.

Study on Space Nonlinear FE Model of Composite Beam Cable-Stayed Bridge with Three Towers

2011 ◽  
Vol 90-93 ◽  
pp. 975-978
Author(s):  
Feng Wang
Keyword(s):  
Composite Beam ◽  
Shell Element ◽  
Element Model ◽  
Internal Force ◽  
Fe Model ◽  
Beam Model ◽  
Single Beam ◽  
Cable Stayed Bridge ◽  
Double Beam ◽  
Nonlinear Finite Element Model

Taking Wuhan Erqi Yangtze River Bridge as an example, based on link element, shell element, and beam element, a double beam nonlinear finite element model is purposed using popular finite analyzing software ANSYS. The internal force and deformation characteristics of composite beam cable-stayed bridge with three towers is analyzed by double beam model, and compared to the single beam. The results show that the double beam nonlinear FE model, which have less freedom and conveniently calculate, can be used to well analyze the nonlinear of composite beam cable-stayed bridge with three towers.

Stiffening Effects of High-Frequency Excitation: Experiments for an Axially Loaded Beam

1999 ◽  
Vol 67 (2) ◽  
pp. 397-402 ◽  
Author(s):  
J. S. Jensen ◽  
D. M. Tcherniak ◽  
J. J. Thomsen
Keyword(s):  
High Frequency ◽  
Harmonic Excitation ◽  
General Tendency ◽  
Beam Model ◽  
Very High Frequency ◽  
Simple Analytical Expression ◽  
Theoretical Predictions ◽  
High Frequency Excitation ◽  
Frequency Excitation ◽  
Very High

According to theoretical predictions one can change the effective stiffness or natural frequency of an elastic structure by employing harmonic excitation of very high frequency. Here we examine this effect for a hinged-hinged beam subjected to longitudinal harmonic excitation. A simple analytical expression is presented, that relates the effective natural frequencies of the beam to the intensity of harmonic excitation. Experiments performed with a laboratory beam confirm the general tendency of this prediction, though there are discrepancies that cannot be explained in the framework of the linear Galerkin-discretized beam model. [S0021-8936(00)01302-7]

scholarly journals Statistical analysis of Stromboli VLP tremor in the band [0.1–0.5] Hz: some consequences for vibrating structures

2006 ◽  
Vol 13 (4) ◽  
pp. 393-400 ◽  
Author(s):  
E. De Lauro ◽  
S. De Martino ◽  
M. Falanga ◽  
M. Palo
Keyword(s):  
Frequency Band ◽  
High Frequency ◽  
Noise Source ◽  
Volcanic Tremor ◽  
Large Data ◽  
Musical Instruments ◽  
Data Set ◽  
Long Period ◽  
Vibrating Structures ◽  
Analyze Time Series

Abstract. We analyze time series of Strombolian volcanic tremor, focusing our attention on the frequency band [0.1–0.5] Hz (very long period (VLP) tremor). Although this frequency band is largely affected by noise, we evidence two significant components by using Independent Component Analysis with the frequencies, respectively, of ~0.2 and ~0.4 Hz. We show that these components display wavefield features similar to those of the high frequency Strombolian signals (>0.5 Hz). In fact, they are radially polarised and located within the crater area. This characterization is lost when an enhancement of energy appears. In this case, the presence of microseismic noise becomes relevant. Investigating the entire large data set available, we determine how microseismic noise influences the signals. We ascribe the microseismic noise source to Scirocco wind. Moreover, our analysis allows one to evidence that the Strombolian conduit vibrates like the asymmetric cavity associated with musical instruments generating self-sustained tones.

The SIRIO satellite, 1968––1977: Between scientific engagement and managerial inexperience

2004 ◽  
Vol 34 (2) ◽  
pp. 371-398
Author(s):  
LUCIA ORLANDO
Keyword(s):  
International Economic ◽  
Organizational Structure ◽  
Frequency Band ◽  
High Frequency ◽  
Aerospace Industry ◽  
Space Research ◽  
High Frequency Band ◽  
Political Uncertainty ◽  
The 1960S ◽  
Super High Frequency

ABSTRACT: The story of the first Italian communications satellite, SIRIO, started in 1968, after the failure of the European project for the vector ELDO-PAS. The story up to the launch in 1977 involved the encumbering legacy of the San Marco satellite's success in the 1960s, political uncertainty in Italy, international economic crises of the 1970s, an overtly complex management system, and an inexperienced aerospace industry. Despite these handicaps, SIRIO won the race with its nearest competitor, the European satellite OTS, which had a similar research aim in the super high frequency band. In addition to collecting a large amount of useful data, SIRIO catalyzed the process for developing an improved organizational structure for Italian space research.

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