High Speed Rail Short Bridge-Track-Train Interaction Based on the Decoupled Equations of Motion in the Finite Element Domain

2016 ◽  
Author(s):  
Said I. Nour ◽  
Mohsen A. Issa
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Numerical Solutions ◽  
Equations Of Motion ◽  
Rotational Inertia ◽  
Force Model ◽  
Inertia Effects ◽  
Contact Points ◽  
Short Span ◽  
Track Bridge

The interaction between the train, track, and bridge was considered as an interaction between two decoupled subsystems. A first subsystem consisted of the train vehicle simulated as a four-wheelset mass-spring-damper system having two layers of suspensions and ten degrees of freedom. A second subsystem consisted of the track-bridge system assumed to be a top rail beam and a bottom bridge beam coupled by continuous springs and dampers representing the elastic properties of the trackbed smeared over the spacing of the railway ties. The bridge supports were assumed to be rigid or flexible. The equations of motion of a finite element form were derived for each subsystem independently by means of the Newton’s second law. The dynamic interaction between the moving vehicle of the first subsystem and the stationary underlying track-bridge structure of the second subsystem was established by means of a no-separation constraint equation in the contact points between the wheels and the rails. The proposed two-dimensional analysis was intended to accurately describe the vertical behavior of short span bridges subjected to high-frequency excitations due to the passage of high speed trains; therefore, shear deformations, rotational inertia effects, and consistent mass matrices were adopted in the mathematical model. Numerical solutions of the decoupled equations of motion for both subsystems were obtained with the step-by-step direct integration in the time domain using HHT alpha method with a special scheme in the contact interface. The solution accuracy of the proposed method was validated against responses obtained from a semi-analytical method of a train car travelling over a simply supported bridge. The practical engineering application was demonstrated with a case study investigating effects of key parameters in the behavior of a ballasted short span railway bridge. Compared with the moving force model, results showed that for bridges with rigid supports both the vehicle interaction and trackbed produce lower peak responses at resonance speeds with the latter being more significant. However an increase in support flexibility had a greater impact across all speeds in increasing the bridge responses.

A modified damping model of vector form intrinsic finite element method for high-speed spiral bevel gear dynamic characteristics analysis

2021 ◽  
pp. 030932472110188
Author(s):  
Xiangying Hou ◽  
Yuzhe Zhang ◽  
Hong Zhang ◽  
Jian Zhang ◽  
Zhengminqing Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Numerical Solutions ◽  
Bevel Gear ◽  
Spiral Bevel Gear ◽  
Vector Form ◽  
Good Efficiency ◽  
Spiral Bevel ◽  
Damping Model

The vector form intrinsic finite element (VFIFE) method is springing up as a new numerical method in strong non-linear structural analysis for its good convergence, but has been constricted in static or transient analysis. To overwhelm its disadvantages, a new damping model was proposed: the value of damping force is proportional to relative velocity instead of absolute velocity, which could avoid inaccuracy in high-speed dynamic analysis. The accuracy and efficiency of the proposed method proved under low speed; dynamic characteristics and vibration rules have been verified under high speed. Simulation results showed that the modified VFIFE method could obtain numerical solutions with good efficiency and accuracy. Based on this modified method, high-speed vibration rules of spiral bevel gear pair under different loads have been concluded. The proposed method also provides a new way to solve high-speed rotor system dynamic problems.

Simulation of Finite Element Analysis for Cutting Force of High-Speed Dry Gear Milling by Flying Cutter

2011 ◽  
Vol 86 ◽  
pp. 100-103
Author(s):  
Qian Guo ◽  
Chao Lin ◽  
Wei Quan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Comparative Analysis ◽  
Cutting Force ◽  
High Speed ◽  
Cutting Parameters ◽  
Force Model ◽  
Cutting Force Model ◽  
Element Analysis ◽  
Gear Hobbing

This paper makes the emulate experimental research of cutting force in high-speed dry gear milling by flying cutter with finite element analysis method by using the established cutting force model yet, makes the comparative analysis for the result of simulation experiment and theoretical calculation, verifies the correctness of cutting force model and calculation method, makes the comparative analysis for the influencing relations and changing laws of cutting force and cutting parameters and so many factors, and reveals the cutting mechanism of high-speed dry gear milling by flying cutter initially. By the research of this paper, it provides basic theory for subsequent cutting machine technology of high-speed dry gear hobbing, and establishes the theoretical basis for the spread and exploitation of this technology.

Stability Analysis of High-Speed Railway Vehicle Based on Multibody Dynamics Analysis

2013 ◽  
Vol 392 ◽  
pp. 156-160
Author(s):  
Ju Seok Kang
Keyword(s):  
Stability Analysis ◽  
Multibody Dynamics ◽  
High Speed ◽  
Equations Of Motion ◽  
Contact Forces ◽  
Design Parameters ◽  
Railway Vehicle ◽  
Dynamics Analysis ◽  
Contact Points ◽  
The Stability

Multibody dynamics analysis is advantageous in that it uses real dimensions and design parameters. In this study, the stability analysis of a railway vehicle based on multibody dynamics analysis is presented. The equations for the contact points and contact forces between the wheel and the rail are derived using a wheelset model. The dynamics equations of the wheelset are combined with the dynamics equations of the other parts of the railway vehicle, which are obtained by general multibody dynamics analysis. The equations of motion of the railway vehicle are linearized by using the perturbation method. The eigenvalues of these linear dynamics equations are calculated and the critical speed is found.

On the Elastic Bending of Columns Due to Dynamic Axial Forces Including Effects of Axial Inertia

1960 ◽  
Vol 27 (1) ◽  
pp. 125-131 ◽  
Author(s):  
Eugene Sevin
Keyword(s):  
Numerical Solutions ◽  
Equations Of Motion ◽  
Sine Wave ◽  
Elastic Response ◽  
Secondary Importance ◽  
Inertia Effects ◽  
Elastic Bending ◽  
Axial Forces ◽  
Compression Members ◽  
Constant Rate

This study is concerned with the influence of axial inertia upon the elastic bending motion of initially slightly curved columns acted on by time-dependent axial forces. The equations of motion include both axial inertia and nonlinear strain terms. Numerical solutions were obtained for a similar problem previously studied by Hoff [1] but in which axial-inertia effects were neglected; i.e., the problem of a simply supported column initially bent in the shape of a half sine wave and loaded by displacing one end axially at a constant rate. The range of solutions pertains to conventional structural compression members (slenderness ratios less than 150), and to minimum rates of loading compatible with elastic response of common engineering materials. This study suggests that axial-inertia effects are of secondary importance in so far as the gross elastic response of conventional structural columns is concerned.

scholarly journals Dynamics Analysis of Unbalanced Motorized Spindles Supported on Ball Bearings

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Junfeng Liu ◽  
Tao Lai ◽  
Xiaoan Chen
Keyword(s):  
High Speed ◽  
Magnetic Force ◽  
Numerical Solutions ◽  
Dynamic Properties ◽  
Lyapunov Stability Theory ◽  
Force Model ◽  
Proposed Model ◽  
Dynamic Operating ◽  
Motorized Spindles ◽  
Good Agreement

This paper presents an improved dynamic model for unbalanced high speed motorized spindles. The proposed model includes a Hertz contact force model which takes into the internal clearance and an unbalanced electromagnetic force model based on the energy of the air magnetic field. The nonlinear characteristic of the model is analysed by Lyapunov stability theory and numerical analysis to study the dynamic properties of the spindle system. Finally, a dynamic operating test is carried out on a DX100A-24000/20-type motorized spindle. The good agreement between the numerical solutions and the experimental data indicates that the proposed model is capable of accurately predicting the dynamic properties of motorized spindles. The influence of the unbalanced magnetic force on the system is studied, and the sensitivities of the system parameters to the critical speed of the system are obtained. These conclusions are useful for the dynamic design of high speed motorized spindles.

Analysis of a High-Speed Flexible Four-Bar Linkage: Part I—Formulation and Solution

1989 ◽  
Vol 111 (1) ◽  
pp. 35-41 ◽  
Author(s):  
F. W. Liou ◽  
A. G. Erdman
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Equations Of Motion ◽  
Computer Code ◽  
Element Analysis ◽  
Virtual Displacement ◽  
Axial Forces ◽  
Direct Integration Method ◽  
Analysis Computer ◽  
Four Bar Linkage

Derived from the principle of virtual displacement, a general finite element analysis computer code (FEMAP) of the flexible four-bar linkage is developed on the Apollo computer. In this part, virtual displacement method is presented as a basic theory for the general formulation of the equations of motion. Based on these results, a general finite element computer code of planar four-bar linkage is developed. All the links of the mechanism are considered to be flexible. The nonlinear terms such as coupling between the rigid body and elastic deformation terms and the effect of the axial forces are included. The Newmark direct integration method is used as solution scheme.

A Refined Model for a Piezoelectric Transformer

2001 ◽  
Author(s):  
Wolfgang E. Seemann ◽  
Rainer Gausmann
Keyword(s):  
Finite Element ◽  
Equations Of Motion ◽  
Wave Length ◽  
Analytical Models ◽  
Piezoelectric Transformer ◽  
Element Analysis ◽  
Load Impedance ◽  
Inertia Effects ◽  
Rod Theory ◽  
University Of Technology

Abstract This paper is dedicated to Prof. Peter Hagedorn, Darmstadt University of Technology, Germany, on the occasion of his 60th birthday. Usually piezoelectric actuators are nowadays simulated with the help of finite element codes. Analytical models are only used for very simple geometries like beams and plates or in those cases where piezoelectric patches are bonded to a beam or plate. Examples can be found in literature. However, it has to be kept in mind that there are still some problems for which standard finite element codes like ANSYS might get difficulties. One such problem is a piezoelectric transformer with an arbitrary load impedance connected to the electrodes of one of the piezoceramics. Such a system is investigated in this paper. To obtain results which are still valid if the diameter of the rod is not small compared to the wave length, a refined rod theory is used which takes into consideration also the inertia effects due to transverse contraction. To derive the equations of motion and the boundary conditions for such a system Hamilton’s principle for electromechanical systems is used. The equations of motion are solved and compared with experimental results. A comparison with results of a finite element analysis is also given for one special case which could be handled by ANSYS.

The Characteristic Analysis of Vibration for High-Speed Train-Ballastless Track-Bridge System Base on A Hybrid FE-SEA Method

2012 ◽  
Vol 226-228 ◽  
pp. 387-391
Author(s):  
Wen Jun Luo ◽  
Xiao Yan Lei ◽  
Song Liang Lian ◽  
Lin Ya Liu
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Power Input ◽  
Characteristic Analysis ◽  
State Response ◽  
Complex Dynamic Systems ◽  
Ballastless Track ◽  
Track Bridge ◽  
Bridge System

A hybrid method combining FE and SEA was recently presented for predicting the steady-state response of vibro-acoustic systems. The new method is presented for the analysis of complex dynamic systems which is based on partitioning the system degrees of freedom into a ‘‘global’’ set and a ‘‘local’’ set. The global equations of motion are formulated and solved by using the finite element method (FEM).The local equations of motion are formulated and solved by using statistical energy analysis (SEA). The power input from the global degrees of freedom. This paper deduces the theory for the beam element , and Train-Ballastless Track-Bridge System provides an application, and it showed that the method yields very good results .

Generalized Equations of Motion for the Dynamic Analysis of Elastic Mechanism Systems

1984 ◽  
Vol 106 (4) ◽  
pp. 243-248 ◽  
Author(s):  
D. A. Turcic ◽  
Ashok Midha
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Single Type ◽  
Generalized Equations ◽  
Element Analysis ◽  
Beam Elements ◽  
Elastic Mechanism ◽  
Element Type

Until recently, vibration effects have generally been neglected in the design of high-speed machines and mechanisms. This has been primarily due to the complexity of the mathematical analysis of mechanisms with elastic links. With the advent of high-speed computers and structural dynamics techniques, such as finite element analysis, this is no longer regarded as such a formidable task. To date, with few exceptions, the analysis of elastic mechanism systems have been limited to a single type of mechanism (i.e., a four-bar or slider-crank) modeled with a small number of simple finite elements (usually beam elements). This paper develops the generalized equations of motion for elastic mechanism systems by utilizing finite element theory. The derivation and final form of the equations of motion provide the capability to model a general two- or three-dimensional complex elastic mechanism, to include the nonlinear rigid-body and elastic motion coupling terms in a general representation, and to allow any finite element type to be utilized in the model. A discussion of a solution method, applications, as well as an experimental investigation of an elastic four-bar mechanism will be presented in subsequent publications.

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