scholarly journals Model Based Research of Dynamic Performance of Shaft-Bearing System in High-Speed Field

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Teng Hu ◽  
Guofu Yin ◽  
Mingnan Sun
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Static Condition ◽  
Influential Factor ◽  
Fe Model ◽  
Idle State ◽  
Gyroscopic Moment ◽  
Nonmonotonic Variation ◽  
Moment Effect ◽  
Bearing System

Dynamic performance of the high-speed running shaft-bearing system (SBS) is different from that of idle state system due to the high-speed effects (HSE), including shaft centrifugal force, gyroscopic moment, and nonlinear bearing operational stiffness. In this paper, aiming at improving the operation stability, dynamic performance of SBS operating in high-speed field is investigated based on a finite element (FE) dynamic model. Firstly, the Timoshenko beam elements are applied to develop the SBS FE model with full consideration of HSE. Secondly, idle state frequency response function at the front tip is obtained analytically and experimentally to validate that the FE model can illustrate the system dynamic behaviors in static condition. Finally, by substituting various rotational velocities into the FE model, the HSE on system natural frequencies are studied one by one as well as together. The results show that, when bearing is being extremely light preloaded, SBS frequencies are affected by the HSE of shaft more than bearing, especially where the gyroscopic moment effect of shaft is the most influential factor. Moreover, the nonmonotonic variation of bearing operational stiffness is analyzed. The “stiffen” phenomenon explained in this paper provides a more comprehensive understanding of the nonlinear bearing operational stiffness.

On The Steady State and Dynamic Performance Characteristics of Floating Ring Bearings

1981 ◽  
Vol 103 (3) ◽  
pp. 389-397 ◽  
Author(s):  
Chin-Hsiu Li ◽  
S. M. Rohde
Keyword(s):  
Steady State ◽  
Linear Theory ◽  
High Speed ◽  
Dynamic Performance ◽  
Equations Of Motion ◽  
Nonlinear Behavior ◽  
Journal Bearings ◽  
Transient Problem ◽  
The Stability ◽  
Bearing System

An analysis of the steady state and dynamic characteristics of floating ring journal bearings has been performed. The stability characteristics of the bearing, based on linear theory, are given. The transient problem, in which the equations of motion for the bearing system are integrated in real time was studied. The effect of using finite bearing theory rather than the short bearing assumption was examined. Among the significant findings of this study is the existence of limit cycles in the regions of instability predicted by linear theory. Such results explain the superior stability characteristics of the floating ring bearing in high speed applications. An understanding of this nonlinear behavior, serves as the basis for new and rational criteria for the design of floating ring bearings.

Insight Into the Design of Blast-Mitigating Floor Mats Using Design of Experiments

2019 ◽  
Author(s):  
Hisham Kamel
Keyword(s):  
Design Of Experiments ◽  
Computational Study ◽  
Close Contact ◽  
Dynamic Performance ◽  
Experimental Tests ◽  
Element Model ◽  
Influential Factor ◽  
Fe Model ◽  
Energy Absorbing ◽  
Insight Into

Abstract Recently, Improvised explosive devices (IEDs) have evolved into a major and significant threat inflicting substantial human casualties and property damage. The majority of injuries are to the lower extremities since they are in close contact to vehicle floor. Floor mats have been developed to mitigate the effects of IEDs blasts. This paper reports a computational study on the energy absorbing behavior of a novel commercial floor mat — Skydex — for foot protection. The design of experiments (DOE) approach was applied to investigate the effect of shape variations on the dynamic performance of a finite element model of Skydex. The FE model was verified using experimental tests on samples produced using 3D printing technique. The DOE approach revealed significant insight into the design of Skydex. It confirmed that shape variables have strong effect on the amount of energy absorbed and the transmitted load. DOE specifically identified the radius of the mid-section of Skydex as the most influential factor in controlling the mode of deformation under compression. In addition, it uncovered the interaction effect between the radius of curvatures of the two hemispheres and upper and lower radii. Finally, DOE revealed the bi-trade-off relations between energy absorbed, transmitted load and mass. These were shown in meaningful and helpful plots which will help the development of Skydex design.

On the Coupling of Foil Bearing Supported Rotors: Part 1 — Analysis

2007 ◽  
Author(s):  
Hooshang Heshmat ◽  
James F. Walton ◽  
Crystal A. Heshmat
Keyword(s):  
Dynamic Characteristics ◽  
High Speed ◽  
Ball Bearing ◽  
Dynamic Performance ◽  
Rotor Systems ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Flexible Rotors ◽  
Coupling Dynamic ◽  
Bearing System

The expanded application of high-speed rotor systems operating on compliant foil bearings will be greatly enhanced with the ability to adequately couple multiple shaft systems with differing bearing systems and dynamic performance. In this paper the results of an analytical tradeoff study assessing coupling dynamic characteristics and their impact on coupled rotor-bearing system dynamics are presented. This analysis effort was completed in an effort to establish the form of characteristics needed to couple foil bearing supported rotors to ball bearing supported rotors, other foil bearing supported rotors as well as coupling rigid and flexible rotors both supported on foil bearings. The conclusions from this study indicate that with appropriate coupling design, a wide array of foil bearing supported rotor systems may be successfully coupled.

Investigation of rotor–gas foil bearing system and its application for an ultra-high-speed permanent magnet synchronous motor

2021 ◽  
pp. 135065012110317
Author(s):  
Jiale Tian ◽  
Baisong Yang ◽  
Sheng Feng ◽  
Lie Yu ◽  
Jian Zhou
Keyword(s):  
Permanent Magnet ◽  
High Speed ◽  
Dynamic Performance ◽  
Permanent Magnet Synchronous Motor ◽  
Synchronous Motor ◽  
Rotating Speed ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Ultra High Speed ◽  
Bearing System

In this study, an ultra-high-speed rotor–gas foil-bearing system is designed and applied to a permanent magnet synchronous motor. Gas foil journal bearings and gas foil thrust bearings are used to provide journal and axial support to the rotor, respectively. The bearings are analyzed theoretically considering the nonlinear deflection of the top foil, and the static and dynamic characteristics are obtained with which the rotor dynamic performances of the tested rotor are calculated using the finite element method. During the experiment, the permanent magnet synchronous motor can operate stably at 94,000 r/min, which demonstrates a great dynamic performance of the gas foil bearings and the stability that it provides to the entire system. The sub-synchronous vibration also occurs when the rotating speed reaches 60,000 r/min and as the speed keeps rising, the amplitude of such vibration increases, which will contribute to the destabilization of the rotor–gas foil-bearing system. Finally, the axial force of the rotor is calculated theoretically as well as measured directly by four micro force sensors mounted in the thrust end cover of the permanent magnet synchronous motor. The experimental results presented in this article are expected to provide a useful guide to the design and analysis of the rotor–gas foil-bearing system and high-speed permanent magnet synchronous motor.

Performance of Two Lobe Multirecess Hybrid Journal Bearing Compensated With Capillary Restrictor

2007 ◽  
Author(s):  
Prashant Kushare ◽  
Satish C. Sharma ◽  
S. C. Jain ◽  
J. Sharana Basavaraja
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Dynamic Performance ◽  
Journal Bearings ◽  
Performance Characteristics ◽  
Favourable Effect ◽  
Improved Performance ◽  
Stiffness And Damping ◽  
Offset Factor ◽  
Bearing System

Multirecess hydrostatic/hybrid journal bearings are being used in many applications owing to their excellent characteristics. The Noncircular journal bearing configurations too are quite frequently used in high speed machinery as they are efficient, less costly and provide better shaft stability. The Two lobe bearing (elliptical bearing) are among the commonly used noncircular journal bearing configuration. The multilobe multirecess hybrid journal bearings have been developed to combine the features of noncircular and circular hybrid journal bearing configurations. In the present work a theoretical investigation of a two lobe multirecess hydrostatic/hybrid journal bearing system have been carried out. The multilobe journal bearing configuration is designed as an arc of the circle with the centre points placed on the symmetry line of the single lobe. The journal offset has been accounted by defining an offset factor ‘δ’. The finite element method has been used to solve the Reynolds equation governing the flow of lubricant in the clearance space of the journal bearing system. The bearing static and dynamic performance characteristics have been presented for the various values of the offset factors (0.75, 1, 1.25 and 1.50) for hybrid mode of operation of the bearing. The simulated results of the studies reveals that, a two lobe recessed hybrid journal bearing provides an improved performance in respect of fluid film stiffness and damping coefficients as compared to that of circular recessed journal bearing. It has been observed that for a multilobe bearing having offset factor more than one has a favourable effect on the dynamic performance characteristics of the two lobe bearing.

Dynamic Performance of High-Speed Electric Multiple Unit within Multi-Body System Simulation

2019 ◽  
Vol 12 (4) ◽  
pp. 339-349
Author(s):  
Junguo Wang ◽  
Daoping Gong ◽  
Rui Sun ◽  
Yongxiang Zhao
Keyword(s):  
High Speed ◽  
Rapid Development ◽  
Dynamic Performance ◽  
Body System ◽  
High Speed Railway ◽  
Evaluation Indexes ◽  
Actual Operation ◽  
Multiple Unit ◽  
The Stability ◽  
Multi Body

Background: With the rapid development of the high-speed railway, the dynamic performance such as running stability and safety of the high-speed train is increasingly important. This paper focuses on the dynamic performance of high-speed Electric Multiple Unit (EMU), especially the dynamic characteristics of the bogie frame and car body. Various patents have been discussed in this article. Objective: To develop the Multi-Body System (MBS) model of EMU, verify whether the dynamic performance meets the actual operation requirements, and provide some useful information for dynamics and structural design of the proposed EMU. Methods: According to the technical characteristics of a typical EMU, a MBS model is established via SIMPACK, and the measured data of China high-speed railway is taken as the excitation of track random irregularity. To test the dynamic performance of the EMU, including the stability and safety, some evaluation indexes such as wheel-axle lateral forces, wheel-axle lateral vertical forces, derailment coefficients and wheel unloading rates are also calculated and analyzed in detail. Results: The MBS model of EMU has better dynamic performance especially curving performance, and some evaluation indexes of the stability and safety have also reached China’s high-speed railway standards. Conclusion: The effectiveness of the proposed MBS model is verified, and the dynamic performance of the MBS model can meet the design requirements of high-speed EMU.

Dynamic Performance of HTS Maglev and Comparisons with Another Two Types of High-Speed Railway Vehicles

Cryogenics ◽  
2021 ◽  
pp. 103321
Author(s):  
Yuhang Yuan ◽  
Jipeng Li ◽  
Zigang Deng ◽  
Zhehao Liu ◽  
Dingding Wu ◽  
...  
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
High Speed Railway ◽  
Railway Vehicles ◽  
Hts Maglev

scholarly journals A Practical Numerical Approach to Characterizing Non-Linear Shrinkage and Optimizing Dimensional Deviation of Injection-Molded Small Module Plastic Gears

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2092
Author(s):  
Xiansong He ◽  
Wangqing Wu
Keyword(s):  
Injection Molding ◽  
High Speed ◽  
Numerical Approach ◽  
Linear Shrinkage ◽  
Influential Factor ◽  
Dimensional Deviation ◽  
Non Linear ◽  
Injection Molded ◽  
Plastic Gears ◽  
Circle Diameter

This paper was aimed at finding out the solution to the problem of insufficient dimensional accuracy caused by non-linear shrinkage deformation during injection molding of small module plastic gears. A practical numerical approach was proposed to characterize the non-linear shrinkage and optimize the dimensional deviation of the small module plastic gears. Specifically, Moldflow analysis was applied to visually simulate the shrinkage process of small module plastic gears during injection molding. A 3D shrinkage gear model was obtained and exported to compare with the designed gear model. After analyzing the non-linear shrinkage characteristics, the dimensional deviation of the addendum circle diameter and root circle diameter was investigated by orthogonal experiments. In the end, a high-speed cooling concept for the mold plate and the gear cavity was proposed to optimize the dimensional deviation. It was confirmed that the cooling rate is the most influential factor on the non-linear shrinkage of the injection-molded small module plastic gears. The dimensional deviation of the addendum circle diameter and the root circle diameter can be reduced by 22.79% and 22.99% with the proposed high-speed cooling concept, respectively.

A Nonlinear Rail Vehicle Dynamics Computer Program SAMS/Rail: Part 1—Theory and Formulations

2009 ◽  
Author(s):  
Khaled E. Zaazaa ◽  
Brian Whitten ◽  
Brian Marquis ◽  
Erik Curtis ◽  
Magdy El-Sibaie ◽  
...  
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Contact Element ◽  
Contact Forces ◽  
Simulation Code ◽  
Vehicle Performance ◽  
Normal Contact ◽  
Advantages And Disadvantages ◽  
High Speed Trains

Accurate prediction of railroad vehicle performance requires detailed formulations of wheel-rail contact models. In the past, most dynamic simulation tools used an offline wheel-rail contact element based on look-up tables that are used by the main simulation solver. Nowadays, the use of an online nonlinear three-dimensional wheel-rail contact element is necessary in order to accurately predict the dynamic performance of high speed trains. Recently, the Federal Railroad Administration, Office of Research and Development has sponsored a project to develop a general multibody simulation code that uses an online nonlinear three-dimensional wheel-rail contact element to predict the contact forces between wheel and rail. In this paper, several nonlinear wheel-rail contact formulations are presented, each using the online three-dimensional approach. The methods presented are divided into two contact approaches. In the first Constraint Approach, the wheel is assumed to remain in contact with the rail. In this approach, the normal contact forces are determined by using the technique of Lagrange multipliers. In the second Elastic Approach, wheel/rail separation and penetration are allowed, and the normal contact forces are determined by using Hertz’s Theory. The advantages and disadvantages of each method are presented in this paper. In addition, this paper discusses future developments and improvements for the multibody system code. Some of these improvements are currently being implemented by the University of Illinois at Chicago (UIC). In the accompanying “Part 2” and “Part 3” to this paper, numerical examples are presented in order to demonstrate the results obtained from this research.

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