Modal and Local Modal Analysis of High Speed Train Car-Body

2012 ◽  
Vol 215-216 ◽  
pp. 800-803
Author(s):  
Tian Li Chen ◽  
Yao Hui Lu ◽  
Jing Zeng ◽  
Li Min Zhang
Keyword(s):  
Modal Analysis ◽  
Structural Design ◽  
High Speed ◽  
Ride Comfort ◽  
Side Wall ◽  
Local Mode ◽  
Analysis Method ◽  
Local Modes ◽  
Car Body ◽  
Finite Element Software

with the speed rising of railway train and the weight lightening of car-body, the frequency range of car-body is widened and the natural frequency is decreased. Especially, the local modes of car-body are caused by suspension device under the car-body bottom, which lead to large vibration response, influence the ride comfort and fatigue failure of structure. In this paper, the whole mode of car-body was analyzed through finite element software. The local mode of car-body bottom and side wall were computed by method of equivalent stiffness constrain. The results show that the local mode of car-body is mainly caused by asymmetry suspension device. The modal analysis method and local modal analysis method adopted in this essay provide the reference and guide the dynamic structural design.

CLASSIFICATION OF BUCKLING MODES IN STIFFENED FUNCTIONALLY GRADED COMPOSITE TUBES SUBJECT TO BENDING

2021 ◽  
Author(s):  
LUAN TRINH ◽  
PAUL WEAVER
Keyword(s):  
Wall Thickness ◽  
Functionally Graded ◽  
Geometric Parameters ◽  
Mode Shapes ◽  
Local Mode ◽  
Buckling Mode ◽  
Global Mode ◽  
Local Modes ◽  
Linear Discriminant ◽  
Finite Element Software

Bamboo poles, and other one-dimensional thin-walled structures are usually loaded under compression, which may also be subject to bending arising from eccentric loading. Many of these structures contain diaphragms or circumferential stiffeners to prevent cross-sectional distortions and so enhance overall load-carrying response. Such hierarchical structures can compartmentalize buckling to local regions in addition to withstanding global buckling phenomena. Predicting the buckling mode shapes of such structures for a range of geometric parameters is challenging due to the interaction of these global and local modes. Abaqus finite element software is used to model thousands of circular hollow tubes with random geometric parameters such that the ratios of radius to periodic length range from 1/3-1/7, the ratio of wall thickness to radius varies from 1/4-1/10. The material used in this study is a type of bamboo, where the Young’s and shear moduli are point-wise orthotropic and gradually increase in magnitude in the radial direction. Under eccentric loads with varying eccentricity, the structures can buckle into a global mode or local modes within an internode, i.e. periodic unit. Moreover, the local modes may contain only one wave or multiple waves in the circumferential direction. As expected, numerical results show that the global mode is more likely to occur in small and thick tubes, whereas the local modes are observed in larger tubes with a smaller number of circumferential waves present in thicker walls. Also, greater eccentricity pushes the local mode domains towards smaller tubes. An efficient classification method is developed herein to identify the domains of each mode shape in terms of radius, wall thickness and eccentricity. Based on linear discriminant analysis, explicit boundary surfaces for the three domains are defined for the obtained data, which can help designers in predicting the mode shapes of tubular structures under axial bending.

Application of Experimental Modal Analysis Method in Researching of Mechanical Structure Dynamic Characteristics

2013 ◽  
Vol 694-697 ◽  
pp. 370-373
Author(s):  
Zhang Yu ◽  
Wen Zheng Cai
Keyword(s):  
Modal Analysis ◽  
Natural Frequency ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Experimental Modal Analysis ◽  
Analysis Method ◽  
Mechanical Structure ◽  
Vibration Resistance ◽  
Structural Rigidity ◽  
Structure Dynamic

With the purpose of realizing the analysis of mechanical structure dynamic characteristics and inhibit vibration and noise, combined with the analysis of a certain type of high speed sewing machines vibration characteristics, we carry on the concrete experimental modal analysis, and compare the results of the experimental modal analysis with the results of spectrum analysis. The analysis results show that the second order natural frequency of the shell is close to two octaves under the normal working speed of sewing machine and it will lead to resonance. Enhancing the structural rigidity and the natural frequency under this modal to avoid resonance frequency is the key to improve vibration resistance of the structure.

Simulation of Bus Ride Comfort under the Excitation of Road Irregularity

2012 ◽  
Vol 510 ◽  
pp. 249-254 ◽  
Author(s):  
Jin Feng ◽  
Yuan Hua Chen
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Ride Comfort ◽  
Temporal Frequency ◽  
Vertical Vibration ◽  
Fe Model ◽  
Analysis Method ◽  
The Road ◽  
Power Spectral ◽  
Bus Structure

Bus vibration is studied by the finite element method (FEM) base on bus structure model. The bus mathematical model of vertical vibration is established and the vibration response variables were deduced with the modal analysis method. The finite element (FE) model is established and decoupled. The transformational relation between spatial frequency displacement power spectral density (PSD) and temporal frequency displacement PSD and the sampling characteristics of the road irregularity PSD in numerical computation are discussed. Road irregularity load is modeled in software. The FE model is solved using modal analysis method and the acceleration PSD of each keypoint can be gained. Finally, a road test experiment is carried on to verify the simulation results. The example indicated that study on vehicle ride comford by FEM has instructive meaning.

Lateral Dynamics Optimization of a Conventional Railcar

1975 ◽  
Vol 97 (3) ◽  
pp. 293-299 ◽  
Author(s):  
N. K. Cooperrider ◽  
J. J. Cox ◽  
J. K. Hedrick
Keyword(s):  
Constrained Optimization ◽  
High Speed ◽  
Optimization Problem ◽  
Ride Comfort ◽  
Stability Margin ◽  
Railway Vehicle ◽  
Constrained Optimization Problem ◽  
Stroke Length ◽  
Car Body ◽  
Unconstrained Problem

The attempt to develop a railway vehicle that can operate in the 150 to 300-mph(240 to 480-km/h) speed regime is seriously hampered by the problems of ride comfort, curve negotiation, and “hunting.” This latter phenomena involves sustained lateral oscillations that occur above certain critical forward velocities and cause large dynamic loads between the wheels and track as well as contributing to passenger discomfort. This paper presents results of an initial effort to solve these problems by utilizing optimization procedures to design a high speed railway vehicle. This study indicates that the problem is more easily treated as a constrained optimization problem than as an unconstrained problem with several terms in the objective function. In the constrained optimization problem, the critical “hunting” speed was maximized subject to constraints on 1) the acceleration of the car body, 2) the suspension stroke length, and 3) the maximum suspension stroke while negotiating a curve. A simple, three degree-of-freedom model of the rail vehicle was used for this study. Solutions of this constrained problem show that beyond a minimum yaw stiffness between truck and car body the operating speed remains nearly constant. Thus, above this value, the designer may trade off yaw stiffness, wheel tread conicity and stability margin.

Modal Analysis of High-Speed Face Milling System Based on Composite Structure System Analysis Method

2014 ◽  
Vol 800-801 ◽  
pp. 408-413
Author(s):  
Lu Ning Liu ◽  
Zhen Yu Shi ◽  
Zhan Qiang Liu ◽  
Hao Song
Keyword(s):  
Machine Tool ◽  
Modal Analysis ◽  
Composite Structure ◽  
High Speed ◽  
System Analysis ◽  
Face Milling ◽  
Analysis Method ◽  
Milling Cutter ◽  
Structure System ◽  
The Face

This paper adopts composite structure system analysis method to perform modal analysis of high-speed face milling cutter which is mounted on the machine tool through FEM modal analysis. The key problem of this method is to obtain joint surface parameters between the machine tool spindle and face milling cutter through experimental modal analysis and MATLAB software. The joint surface parameters consist of linear stiffness, linear damping, rotation stiffness and rotation damping. After getting the frequency response function (FRF) at the tool tip of the face milling system through experimental modal analysis, the contact surface parameters can be used to eliminate the influence of the machine tool to get modal parameters of the face-milling cutter itself. Based on the finite element model of face milling cutter, composite structure system analysis method can be used easily to acquire the dynamic performance of the face milling system through FEM modal analysis, greatly to improve the reliability of modal analysis, and is helpful to the dynamic design and the structure improvement of high speed face milling cutter.

Vehicle dynamics of a high-speed passenger car due to aerodynamics inside tunnels

2007 ◽  
Vol 221 (4) ◽  
pp. 527-545 ◽  
Author(s):  
B Diedrichs ◽  
M Berg ◽  
S Stichel ◽  
S Krajnović
Keyword(s):  
Vehicle Dynamics ◽  
High Speed ◽  
Ride Comfort ◽  
Sensitivity Study ◽  
Response Analysis ◽  
Vehicle Dynamic ◽  
Aerodynamic Loads ◽  
Car Body ◽  
Unsteady Aerodynamic ◽  
Multi Body

High train speeds inside narrow double-track tunnels using light car bodies can reduce the ride comfort of trains as a consequence of the unsteadiness of the aerodynamics. This fact was substantiated in Japan with the introduction of the series 300 Shinkansen trains more than a decade ago, where the train speed is very high also in relatively narrow tunnels on the Sanyo line. The current work considers the resulting effects of vehicle dynamics and ride comfort with multi-body dynamics using a model of the end car of the German high-speed train ICE 2. The present efforts are different from traditional vehicle dynamic studies, where disturbances are introduced through the track only. Here disturbances are also applied to the car body, which conventional suspension systems are not designed to cope with. Vehicle dynamic implications of unsteady aerodynamic loads from a previous study are examined. These loads were obtained with large eddy simulations based on the geometry of the ICE 2 and Shinkansen 300 trains. A sensitivity study of some relevant vehicle parameters is carried out with frequency response analysis (FRA) and time domain simulations. A comparison of these two approaches shows that results which are obtained with the much swifter FRA technique are accurate also for sizable unsteady aerodynamic loads. FRA is, therefore, shown to be a useful tool to predict ride comfort in the current context. The car body mass is found to be a key parameter for car body vibrations, where loads are applied directly to the car body. For the current vehicle model, a mass reduction of the car body is predicted to be most momentous in the vicinity of 2 Hz.

Based on Analysis of Finite Element Analysis of Automobile Transmission Shaft Comprehensive Optimization

2014 ◽  
Vol 684 ◽  
pp. 341-346
Author(s):  
Heng Yi Yuan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
High Speed ◽  
Ride Comfort ◽  
Element Model ◽  
Drive Shaft ◽  
Element Analysis ◽  
Finite Element Software ◽  
Transmission Shaft

The shaft as an important parts of automobile transmission system, in the process of the car have the effect of rotational speed and torque. Due to the structural characteristics of its low frequency, small stiffness, universal joint, such as the existence of the additional moment drive shaft inevitably exist when high speed vibration phenomenon. So the shaft vibration problems to deal with the vehicle ride comfort, comfort and dynamic performance has important significance. On the basis of the finite element software ANSYS, the physical design of drive shaft. Analyzes the mapping grid finite element model of transmission shaft, facilitate accurate transmission shaft strength calculation. Based on the inherent frequency and vibration model of finite element method to calculate transmission shaft, using experimental modal technology for modal analysis of the shaft, the test results verify the reliability of the finite element model. On this basis, the drive shaft assembly constraint modal finite element analysis, can be used as the basis of further research.

Effect of the Welding Heat Input on Residual Stresses in Butt-Weld of High-Speed Train

2011 ◽  
Vol 337 ◽  
pp. 255-261 ◽  
Author(s):  
Zhong Yin Zhu ◽  
Peng Chen ◽  
Hong Mei Zhou ◽  
Yong Hui Zhu ◽  
Yong Hong Chen ◽  
...  
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Heat Input ◽  
High Speed ◽  
Side Wall ◽  
High Speed Train ◽  
Butt Weld ◽  
Car Body ◽  
Welding Heat Input

Abstract. This study used finite element software SYSWELD to analyze residual stresses in butt-weld between underframe and side wall of high-speed train car body. Based on the thermal-elastic-plastic theory, double ellipsoid heat source model is adopted to simulate the residual stresses under different heat input in the welded joints between underframe and side wall. The residual stresses at the surface of weld specimen were measured experimentally by using the hole-drilling method. The results of the finite element analysis were compared with experimentally measured data to evaluate the accuracy of the finite element modeling. Based on this study, a modelling procedure with reasonable accuracy was developed. The developed finite element modelling was used to study the effects of welding heat input on magnitude and distribution of welding residual stresses in butt-weld of high-speed train car body made of A6N01-T5. The results show the maximum residual stress exists in the welded seam and the adjacent-weld zone, and the residual stress value decreases gradually while the zone is farther from the weld center .Besides, With the increase of the welding heat input, the residual stress value increases gradually.

The Experimental Modal Analysis of High Speed Machining Tool System Based on Integral Polynomial Recognition Method

2012 ◽  
Vol 723 ◽  
pp. 159-163 ◽  
Author(s):  
Fei Xiao ◽  
Xian Li Liu ◽  
Yan Xin Wang ◽  
Li Jia Liu ◽  
Da Qu
Keyword(s):  
Modal Analysis ◽  
High Speed ◽  
Simulation Method ◽  
Experimental Modal Analysis ◽  
Modal Parameters ◽  
High Speed Machining ◽  
Analysis Method ◽  
Recognition Method ◽  
Element Simulation ◽  
Integral Polynomial

According to the principle of the experimental modal analysis, this study is based on tool system of the MIKRON UCP 710 numerical control machining center as test object for experimental modal analysis. Using the integral polynomial recognition method to identify the modal parameters (natural frequency, structural damping, and modal shape), and finally matching the results with the vector analysis method and the finite element simulation method. The results show that integral polynomial recognition method has higher precision than the vector analysis method to identify the multi-degree of freedom system; the experimental modal analysis can also obtain better modal parameters of the structure system, and a higher precision than the finite element simulation method. Obtained the MIKRON UCP 710 high-speed milling center tool system accurate modal parameters provides the necessary theoretical and experimental basis for the further study of the stability properties in the cutting processing of the high speed machining tool system.

scholarly journals Effect of train speed and track geometry on the ride comfort in high-speed railways based on ISO 2631-1

2019 ◽  
Vol 234 (7) ◽  
pp. 765-778
Author(s):  
Chi Liu ◽  
David Thompson ◽  
Michael J Griffin ◽  
Mani Entezami
Keyword(s):  
High Speed ◽  
Dynamic Models ◽  
Ride Comfort ◽  
Railway Vehicle ◽  
Track Geometry ◽  
Car Body ◽  
Flexible Mode ◽  
High Speed Trains ◽  
All Speeds ◽  
Iso 2631

The operational speeds of passenger trains have been increasing and now often exceed 300 km/h. Higher speeds can lead to increased vibration and reduced ride comfort for railway passengers. This study investigates the combined effect of speed and track geometry on vibration discomfort in high-speed trains. Railway vehicle dynamic models with various levels of complexity are used, with the measured geometry of a section of a high-speed track as an input. The models have been calibrated with vibration measurements carried out in a train running over this section of the track and then applied to predict the vibration discomfort at increased speeds. To evaluate the vibration discomfort at speeds up to 400 km/h, information on track geometry should include wavelengths up to at least 150 m. Vertical irregularities have the greatest effect at all speeds but lateral irregularities are also important. Both the vertical and lateral irregularities of a high-speed track should be controlled at wavelengths of 50–100 m that excite rigid modes of the car body, corresponding to frequencies of typically 1–2 Hz. Additionally, vertical irregularities with wavelengths of 5–12 m that excite the fundamental flexible mode of the car body, typically around 10–15 Hz, should also be controlled. The effects of cant, the rates of change of cant, and the radius of vertical curves are also evaluated although they only have a small effect on vibration discomfort.

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