Performance Criteria for High-Speed Crank-and-Rocker Linkages—Part II: Spherical Crank-and-Rocker Linkages

1979 ◽  
Vol 101 (1) ◽  
pp. 26-31 ◽  
Author(s):  
H. Funabashi ◽  
F. Freudenstein
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Performance Criteria ◽  
Link Length ◽  
Angle Variation ◽  
Numerical Examples ◽  
Transmission Angle ◽  
The Dead ◽  
Sine Functions

In Part I proportions were derived for high-speed plane crank-and-rocker mechanisms. In this part, the corresponding developments are given for spherical crank-and-rocker mechanisms. The ratios of the sine functions of the transmission angles and of the rocker accelerations—both at the dead-center positions—remain the static and dynamic performance criteria of the linkage. The results are illustrated by numerical examples, which show the influence of these ratios on the transmission-angle variation, rocker acceleration and the ratio of minimum to maximum link length.

Performance Criteria for High-Speed Crank-and-Rocker Linkages—Part I: Plane Crank-and-Rocker Linkages

1979 ◽  
Vol 101 (1) ◽  
pp. 20-25 ◽  
Author(s):  
H. Funabashi ◽  
F. Freudenstein
Keyword(s):  
High Speed ◽  
Performance Criteria ◽  
Angle Variation ◽  
Pocket Calculator ◽  
Numerical Example ◽  
High Speeds ◽  
Classical Procedure ◽  
Transmission Angle ◽  
Crank Mechanism

Criteria are given for evaluating the performance and determining the dimensions of plane crank-and-rocker mechanisms suitable for operation at high speeds. In contrast to the classical procedure of simulating the acceleration pattern of the slider-crank mechanism by means of centric crank-and-rocker linkages, a family of crank-and-rocker linkages has been found, with a more nearly sinusoidal acceleration pattern, i.e., one which tends more nearly to simulate the acceleration variation of a scotch yoke. At the same time the transmission-angle variation and the ratio of minimum to maximum link lengths is controlled. A pocket-calculator procedure is described and illustrated by means of a numerical example.

Combining Inverse Dynamics With Traditional Mechanism Synthesis to Improve the Performance of High Speed Machinery

2008 ◽  
Author(s):  
Robert Rayner ◽  
M. Necip Sahinkaya ◽  
Ben Hicks
Keyword(s):  
Mechanism Design ◽  
High Speed ◽  
Inverse Dynamics ◽  
Dynamic Performance ◽  
Performance Criteria ◽  
Alternative Mechanism ◽  
Analysis Tool ◽  
Mechanism Synthesis ◽  
Inverse Dynamic ◽  
Modeling And Analysis

This paper describes a unique, computer-based, mechanism design strategy that takes into account both kinematic and dynamic performance criteria at the synthesis stage of the design process. The strategy can be used to investigate improvements in the design of any existing mechanism with geometric redundancy in its output path. By iteratively varying the form of this redundant portion of the output path, alternative potentially better mechanism designs can be generated using a traditional mechanism synthesis and kinematic analysis method. The generated designs with the most desirable kinematic characteristics can be selected and analyzed using a multi-body, dynamic modeling and analysis tool. Using forward and inverse dynamic analysis the quality of the designs can be quantified. This paper describes work done to apply the strategy to an existing mechanism. An alternative mechanism design was identified with superior dynamic qualities. Kinematic performance was not sacrificed.

A General Theory for Synthesizing Crank-Type Four-Bar Function Generators With Transmission Angle Control

1978 ◽  
Vol 45 (2) ◽  
pp. 415-421 ◽  
Author(s):  
Krishna C. Gupta
Keyword(s):  
General Theory ◽  
Least Square ◽  
Angle Variation ◽  
Numerical Examples ◽  
Transmission Angle ◽  
Function Generators

In this paper, the author proposes a general theory for synthesizing crank-type (i.e., crank-rocker and double-crank) four-bar function generators in which the transmission angle variation over a full crank revolution is in a specified range. Precision point as well as least-square designs have been considered in the paper. Applications of the theory are illustrated by means of numerical examples.

Optimization of Crank-and-Rocker Linkages with Size and Transmission Constraints

1979 ◽  
Vol 101 (1) ◽  
pp. 51-57 ◽  
Author(s):  
F. Freudenstein ◽  
Meng Sang Chew
Keyword(s):  
Logical Analysis ◽  
Direct Solution ◽  
Angle Variation ◽  
Numerical Examples ◽  
Transmission Angle ◽  
Transmission Constraints

An algebraic procedure suitable for pocket calculators is derived for the determination of the proportions of a plane crank-and-rocker linkage in which the ratio of largest to smallest link and the transmission-angle variation are prescribed. A logical analysis of the relative lengths of the links leads to a direct solution without algorithms or iteration. The results are illustrated with tables and numerical examples.

A COMPARATIVE STUDY OF CAM MOTIONS FOR HIGH-SPEED SEMI-RIGID FOLLOWER CAM SYSTEMS

1988 ◽  
Vol 12 (3) ◽  
pp. 121-128 ◽  
Author(s):  
P.S. GREWAL ◽  
W.R. NEWCOMBE
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Poor Performance ◽  
Performance Criteria ◽  
Vibrational Response ◽  
High Speeds ◽  
Speed Performance ◽  
Cam Profile ◽  
Torque Values ◽  
Profile Errors

A study is presented on the comparison of all the popular cam motions based on a refined dynamic model which takes into account the effects of cam profile errors and most of the important factors that influence the dynamic performance for a semi-rigid follower cam system. A stochastic model is developed to simulate the input signal resulting from the cam motion, including the deviations due to profile errors. The performance criteria comprise the vibrational response at the follower and the dynamic characteristics at the cam. It has been established that, at high speeds, it is not the vibrational behaviour, but the follower tendency to jump and the maximum contact force and cam torque values which determine the dynamic performance. The Modified-Sine, Simple Harmonic and 3-4-5 Polynomial motions have been shown to exhibit superior high speed performance compared to that of the popular Cycloidal and Modified Trapezoidal motions. Higher-order Polynomial motions give very poor performance at high speeds.

scholarly journals Mathematical Modeling on Statics and Dynamics of Aerostatic Thrust Bearing with External Combined Throttling and Elastic Orifice Fluid Flow Regulation

Lubricants ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 57 ◽  
Author(s):  
Vladimir Kodnyanko ◽  
Stanislav Shatokhin ◽  
Andrey Kurzakov ◽  
Yuri Pikalov
Keyword(s):  
Mathematical Modeling ◽  
High Speed ◽  
Metal Cutting ◽  
Load Capacity ◽  
Dynamic Performance ◽  
Performance Criteria ◽  
Design Parameters ◽  
Machining Accuracy ◽  
Aerostatic Bearing ◽  
Aerostatic Bearings

As aerostatic bearings are used in high-speed metal-cutting machines to increase machining accuracy, there is the need to improve their characteristics, including compliance, which is usually high. In practical applications, a significant reduction of bearing compliance is often necessary, sometimes down to zero and even negative values, to ensure automatic compensation of the elastic deformation in the machine technological system. A decrease in compliance leads to deterioration in the dynamic performance of the bearing, so it is necessary to develop new designs that meet the above requirements. This article considers an aerostatic bearing, in which decrease in compliance is ensured by the use of air throttling with elastic orifices. To ensure its stability, the principle of combined external throttling was applied, which can substantially improve the dynamics of conventional aerostatic bearings. A mathematical model of the elastic orifice deformation was developed, together with the flow rate performance calculation method. The method ensured full qualitative and satisfactory quantitative agreement with the experimental data. The model was used in the mathematical modeling of the aerostatic bearing movement. The article also proposes a method to calculate the static load capacity and compliance of a bearing, as well as a numerical method for fast computation of its dynamic performance, which allows for real-time multi-parameter optimization by the bearing dynamic performance criteria. The study showed that there is an optimal set of design parameters for which low, zero, and negative static compliance of the bearing is ensured, with the necessary stability margin, high speed, and the non-oscillatory nature of the transient processes.

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

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.

A Study on the Method of Vibration Analysis for Korean High Speed Train by the On-Line Test

2006 ◽  
Vol 321-323 ◽  
pp. 1593-1596 ◽  
Author(s):  
Chan Kyoung Park ◽  
Ki Whan Kim ◽  
Jin Yong Mok ◽  
Young Guk Kim ◽  
Seog Won Kim
Keyword(s):  
Vibration Analysis ◽  
High Speed ◽  
Vibration Mode ◽  
Dynamic Performance ◽  
Railway Vehicle ◽  
High Speed Train ◽  
Acceleration Data ◽  
On Line ◽  
System Vibration ◽  
Line Test

The Korean High Speed Train (KHST) has been tested on the Kyongbu high speed line and the Honam conventional line since 2002. A data acquisition system was developed to test and prove the dynamic performance of the KHST, and the system has been found to be very efficient in acquiring multi-channel data from accelerometers located all over the train. Also presented in this paper is an analysis procedure which is simple and efficient in analyzing the acceleration data acquired during the on-line test of the KHST. The understanding of system vibration mode for a railway vehicle is essential to evaluate the characteristics of a dynamic system and to diagnose the dynamic problems of the vehicle system during tests and operations. Methods based on homogeneous linear systems are not realistic because real systems have nonlinear characteristics and are strongly dependent on environmental conditions. In this paper an efficient method of vibration analysis has been proposed and applied for the KHST to evaluate its vibration mode characteristics. The results show that this method is suitable to estimate the system vibration modes of the KHST.

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