Universal Mechanism - the software for modeling of dynamics of mechanical systems: UM Loco

Module for Simulation of Railway Vehicle Dynamics (UM Loco)

The program package includes module UM Loco, which is intended for simulation of dynamics of railway vehicles of different types (diesel and electric locomotives, passenger and freight wagons) in both straight and curve railroad tracks. The simulation is performed in time domain by means of numeric integration of differential or differential-algebraic equations of motion. UM Loco allows the user to create fully parameterized models of vehicles. Geometrical, inertia and force parameters may be specified using identifiers. The parameterization of a model is the base for effective analysis and optimization its dynamical behavior.

In some cases to obtain more accurate solution and/or perform a fatigue analysis it needs to introduce in the model of the vehicle flexible bodies imported from ANSYS or NASTRAN instead rigid ones. It could be done with the help of the UM FEM module.

The paper "Simulation of dynamics of railway vehicles in Universal Mechanism software" (8 pages) is an overview of accumulated experience of using Universal Mechanism (UM) software in railway industry. The list of UM users, applied researches and the Universal Mechanism key features are discussed.

Adequacy of the mathematical models of UM was proved with the help of Manchester Benchmarks, click here for details.

UM allows the user

- to calculate the critical speed;
- to analyze 3D dynamics of a vehicle or a train in time domain on straight track or curves with/without irregularities;
- to analyze vehicle dynamics depending on wheel and rail profiles;
- to create multivariant projects for scanning the vehicle/train dynamics depending on any parameters;
- to compute natural frequencies and modes as well as root locus;
- to create hybrid rigid-elastic models of vehicles;
- to perform a durability analysis of parts of vehicles.


Electric locomotive EP200 with passenger train	Three-piece bogie 18-100

UM Loco features

- wheelset as a standard subsystem;
- automatic calculation of rail/wheel contact forces according to various models of creep forces (Mueller model, FastSim algorithm, modified Kik-Piotrowski method, etc.), multipoint non-Hertzian (non-elliptical) contact is implemented;
- specialized graphical interface for animation of contact forces and contact areas;
- interface for creation of rail and wheel profiles and track irregularities;
- interface for setting curve parameters;
- standard list of variables, which characterize rail/wheel interaction (creepage, creep forces, angle of attack, wear factors, etc., more than 30 performances for each wheel).


Freight car	Electric locomotive VL80

Software verification

Manchester Benchmarks by The Rail Technology Unit of Manchester Metropolitan University is now de-facto standard for verification of software for simulation of railway vehicle dynamics.

“The aim of producing these benchmarks was to allow railway vehicle suspension designers and researchers investigating vehicle dynamic behaviour to assess the suitability of the various software packages that now exist for simulation of such behaviour.”

So called Manchester Benchmarks were published in 1998 and includes prototypes of passenger and freight cars. Results of simulation of test cars from Manchester Benchmarks are now available for most of commercial software and published in [1]. Results of Manchester Benchmarks for Universal Mechanism software are available in 10_UM_Loco_Manchester_benchmarks.pdf (1 Mb).

A number of field and test bench experiments were fulfilled by independent researchers. Sakalo and Kossov in [2, 3] considered dynamics of a TE116 locomotive and drew a conclusion that “… satisfactory convergence of theoretical and experimental values of all considered features are achieved. Divergence between results of computer simulation in UM and field experiments does not exceed 15 %.” Pavlukov and others ran test bench experiments with a freight three-piece bogie. Convergence between results of numerical simulation and test bench experiments within 10% bounds is obtained, [4].

References

1. Iwnicki, Simon D. The Manchester benchmarks for rail vehicle simulation / ed. by S. Iwnicki. - Lisse: Swets & Zeitlinger, 1999. Available on Amazon

2. Kossov, V. S. Reducing dynamical loading of running gears of locomotives and railway track. Doctoral thesis, Kolomna, 2001 (in Russian)

3. Sakalo V.I., Kossov V.S. Contact problems of railway transport. Moscow: Mashinostroenie, 2004. (in Russian)

4. Pogorelov D.Yu., Pavlukov A.E., Yudakova T.A., Kotov S.V. Simulation of contact interactions in multibody system dynamics. / Dynamics, strength and reliability of transport machines / ed. by V.I. Sakalo. Bryansk: Bryansk State Technical University, 2001. P. 11–23. (in Russian)

Our users

Universal Mechanism software is used by the following design institutes, factories and colleges from railway industry:

Australia
WorleyParsons Limited, Melbourne
Institute of Railway Technology, Monash University, Melbourne

Belarus
Belarusian State University of Transport, Gomel

Brazil
TyssenKrupp

Canada
Concordia University

China
Chinese Academy of Railway Sciences (CARS)
CRRC Qingdao Sifang Rolling Stock Research Institute Co., Ltd
East China Jiaotong University
Southwest Jiaotong University
Shijiazhuang Tiedao University
Beijng Jiaotong University
CRRC Nanjing Puzhen Co., Ltd.
Southwest Jiaotong Univeirsity Emei Campus
CRRC Zhuzhou Times New Material Technology Co., Ltd
BYD Company Limited
China Railway Eryuan Engineering Group Co., Ltd.
Tongji University
China Railway Design Corporation
CRRC Zhuzhou Locomotive Co., Ltd.
Shanghai University of Engineering Science
Beijing General Municipal Engineering Design & Reearch Institute Co., Ltd.
CRRC Academy Co., Ltd.
Tsinghua University
Beijing Jiuzhouyigui Environmental Technology Co., Ltd
Hefei University of Technology
Chengdu Xinzhu Road & Bridge Machinery Co., Ltd.
The Hong Kong Polytechnic University