Effect of Service Speed on Dynamic Response of Heavy-Load Depressed Center Flat

2012 ◽  
Vol 226-228 ◽  
pp. 802-806
Author(s):  
Su Xia Zhou ◽  
Teng Long ◽  
Yun Ye Xie ◽  
Ji Long Xie
Keyword(s):  
Dynamic Response ◽  
Rigid Body ◽  
Vertical Vibration ◽  
Elastic Displacement ◽  
Heavy Vehicles ◽  
Heavy Load ◽  
Vibration Displacement ◽  
Flexible Coupling ◽  
Elastic Vibrations ◽  
Vertical Displacements

In order to study the dynamic response characteristics of depressed center flat car with different velocity, based on multi-body system dynamics software SIMPACK, 320t depressed center flat car system rigid body and rigid-flexible coupling-body dynamics model were established and the dynamic response simulation analysis of empty and loaded flat was carried out under several velocities. Then maximal vertical vibration displacement amplitudes and vertical vibration accelerations of depressed centre flat frame under different velocities were obtained. It showed that the maximum accelerations and displacements amplitudes increase with as the speed gradually increased for both empty and heavy vehicles and the trends are similar for the rigid body or rigid-flexible coupling-body. But the values of rigid-flexible coupling-body are bigger than that of rigid body because the elastic vibrations from the depressed center flat frame and all levels of suspension contribut to the vertical displacement. As the speed increases, the vertical displacements of the rigid-flexible coupling-body and the elastic ones response synchronously. The vertical displacements of the empty and heavy vehicles reach their peak values at different speeds and the elastic displacement also has a large proportion, which shows that there are larger elastic vibrations at the speeds. Therefore, it is not suitable for the depressed centre flat to run at very high speeds, and the speed should be confined.

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.

Steady-State Rigid-Body Dynamic Response of Cam-Follower Mechanisms

1994 ◽  
Author(s):  
Andi I. Mahyuddin ◽  
Ashok Midha
Keyword(s):  
Steady State ◽  
Dynamic Response ◽  
Rigid Body ◽  
Angular Speed ◽  
Integration Scheme ◽  
Rigid Body Dynamic ◽  
Speed Variation ◽  
Cam Follower ◽  
Speed Fluctuation ◽  
Body Dynamic

Abstract The camshaft of a cam-follower mechanism experiences a position-dependent moment due to the force exerted on the cam by the follower, causing the angular speed of the camshaft to fluctuate. In this work, a method to expediently predict the camshaft speed fluctuation is developed. The governing equation of motion is derived assuming that the cam-follower system is an ideal one wherein all members are treated as rigid. An existing closed-form numerical algorithm is used to obtain the steady-state rigid-body dynamic response of a machine system. The solution considers a velocity-dependent moment; specifically, a resisting moment is modeled as a velocity-squared damping. The effects of flywheel size and resisting moment on camshaft speed fluctuation are studied. The results compare favorably with those obtained from transient response using a direct integration scheme. The analytical result also shows excellent agreement with the camshaft speed variation of an experimental cam-follower mechanism. The steady-state rigid-body dynamic response obtained herein also serves as a first approximation to the input camshaft speed variation in the dynamic analysis of flexible cam-follower mechanisms in a subsequent research.

On the dynamic response of rigid body assemblies

1986 ◽  
Vol 14 (6) ◽  
pp. 861-876 ◽  
Author(s):  
R. H. Allen ◽  
I. J. Oppenheim ◽  
A. R. Parker ◽  
J. Bielak
Keyword(s):  
Dynamic Response ◽  
Rigid Body

Effect of Gear Tooth Crack on Spur Gear Dynamic Response by Simulation

2011 ◽  
Author(s):  
Yimin Shao ◽  
Xi Wang ◽  
Zaigang Chen ◽  
Teik C. Lim
Keyword(s):  
Dynamic Response ◽  
Gear Tooth ◽  
Sudden Change ◽  
Element Model ◽  
Spur Gear ◽  
Operating Conditions ◽  
Lumped Parameter Model ◽  
Mesh Stiffness ◽  
Heavy Load ◽  
High Rotational Speed

Geared transmission systems are widely applied to transmit power, torque and high rotational speed, and as well as change the direction of rotational motion. Their performances and efficiencies depend greatly on the integrity of the gear structure. Hence, health monitoring and fault detection in geared systems have gained much attention. Often, as a result of inappropriate operating conditions, application of heavy load beyond the designed capacity or end of fatigue life, gear faults frequently occur in practice. When fault happens, gear meshing characteristics, including mesh stiffness that is one of the important dynamic parameters, can be affected. This sudden change in mesh stiffness can induce shock vibration as the faulty gear tooth passes through the engagement zone. In this study, a finite element model representing the crack at the tooth root of a spur gear is developed. The theory is applied to investigate the effect of different crack sizes and the corresponding change in mesh stiffness. In addition, a lumped parameter model is formulated to examine the effect of tooth fault on gear dynamic response.

scholarly journals Soil-Pile Interaction in the Pile Vertical Vibration Based on Fictitious Soil-Pile Model

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
Guodong Deng ◽  
Jiasheng Zhang ◽  
Wenbing Wu ◽  
Xiong Shi ◽  
Fei Meng
Keyword(s):  
Dynamic Response ◽  
Separation Of Variables ◽  
Vertical Vibration ◽  
Dynamic Responses ◽  
Dynamic Force ◽  
Laplace Transform Technique ◽  
Velocity Response ◽  
Pile Interaction ◽  
Pile Model ◽  
Fictitious Soil

By introducing the fictitious soil-pile model, the soil-pile interaction in the pile vertical vibration is investigated. Firstly, assuming the surrounding soil of pile to be viscoelastic material and considering its vertical wave effect, the governing equations of soil-pile system subjected to arbitrary harmonic dynamic force are founded based on the Euler-Bernoulli rod theory. Secondly, the analytical solution of velocity response in frequency domain and its corresponding semianalytical solution of velocity response in time domain are derived by means of Laplace transform technique and separation of variables technique. Based on the obtained solutions, the influence of parameters of pile end soil on the dynamic response is studied in detail for different designing parameters of pile. Lastly, the fictitious soil-pile model and other pile end soil supporting models are compared. It is shown that the dynamic response obtained by the fictitious soil-pile model is among the dynamic responses obtained by other existing models if there are appropriate material parameters and thickness of pile end soil for the fictitious soil-pile model.

Development of Test Rig for High-Speed Railway Rolling Bearings

2011 ◽  
Vol 101-102 ◽  
pp. 702-707 ◽  
Author(s):  
Zhao Dong Huang ◽  
Bo Qian Fan ◽  
Xiao Ping Ouyang ◽  
Ling Ling Xu ◽  
Zhi Gang Wang
Keyword(s):  
High Speed ◽  
High Performance ◽  
Rolling Bearing ◽  
Main Shaft ◽  
Heavy Vehicles ◽  
Test Rig ◽  
Rolling Bearings ◽  
Heavy Load ◽  
High Speed Railway ◽  
Mechanical Structure

The rolling bearing test rig for heavy vehicles often works under heavy load and high speed, thus it requires high performance for the main shaft and mechanical structure. In this paper a design of test rig for high-speed railway rolling bearings is presented, in which a new structure is adopted to reduce the load on the support bearings. The basic idea is to position the load in a way that they can be balanced by each other.

Modeling of Flexible Coupling to Connect Misaligned Flexible Rotors Supported on Ball Bearings

2014 ◽  
Author(s):  
T. C. Gupta ◽  
K. Gupta
Keyword(s):  
Dynamic Response ◽  
Stiffness Matrix ◽  
Ball Bearing ◽  
Radial Clearance ◽  
Fe Model ◽  
Ball Bearings ◽  
Flexible Coupling ◽  
Flexible Rotors ◽  
Deep Groove ◽  
Coupling Stiffness

Parallel or/and angular misalignment between rotors connected by flexible coupling causes deformation of coupling elements and rotor shafts both. The forces and moments from flexible coupling act on driver and driven rotors simultaneously and depend upon dynamic response of coupled rotor system. The authors’ aim in the present work is to propose a methodology to incorporate the coupling stiffness matrix and coupling loads into the finite element model of flexibly coupled flexible rotors supported on deep groove ball bearings. The coefficients of coupling stiffness matrix and coupling loads are nonlinear and depend upon the amount of parallel and angular misalignments. To segregate the effect of nonlinear stiffness of coupling on the dynamic response of the system, the stiffness of ball bearing is initially considered to be linear. Thereafter, ball bearing nonlinearities arising from radial clearance, Hertzian deformation of balls and races, and varying compliance effect are included into the FE model of the system. Considering different types of misalignments in succession and combination, the dynamic response is characterized by the presence of 1N, 2N and other super or sub harmonics. The misalignment in one plane is found to affect the dynamic response in both the orthogonal planes. Comparing to the stiffness of flexible coupling, the stiffness of ball bearing is of higher order and therefore, nonlinear coupling forces and moments have dominant influence on the dynamic response of the system.

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