Methodology for Optimization of Friction Draft Gear Design

2014 ◽  
Author(s):  
Qing Wu ◽  
Colin Cole ◽  
Maksym Spiryagin
Keyword(s):  
Dynamics Simulation ◽  
Rolling Stock ◽  
System Failures ◽  
Gear Design ◽  
Simulation Techniques ◽  
Coupling System ◽  
Heavy Haul ◽  
Draft Gear ◽  
Train Dynamics ◽  
Heavy Haul Trains

Evidence gathered from industry indicates that railway coupling system failures have become a limitation for further developments of heavy haul trains. Friction draft gears have implications for both longitudinal train dynamics and rolling stock fatigue; therefore, optimization of friction draft gears could be a possible solution to conquer the limitation. In this paper, a methodology for optimization of friction draft gear design based on an advanced friction draft gear model is proposed. The methodology proposes using simulation techniques such as longitudinal train dynamics simulation and a Genetic Algorithm to develop improved parameters.

Development and validation of a new code for longitudinal train dynamics simulation

2020 ◽  
pp. 095440972092349
Author(s):  
Nicola Bosso ◽  
Matteo Magelli ◽  
Nicolò Zampieri
Keyword(s):  
Experimental Tests ◽  
Dynamics Simulation ◽  
Essential Information ◽  
Signaling Systems ◽  
Railway Systems ◽  
Heavy Haul ◽  
Train Dynamics ◽  
And Performance ◽  
Heavy Haul Trains ◽  
Development And Validation

Longitudinal train dynamics have a significant impact on both safety and performance of railway systems. Numerical simulation of long heavy haul trains can thus provide essential information for the development of diagnostic and signaling systems as well as coupling elements and braking systems. Long trains are usually modeled by considering only the longitudinal degree of freedom and by adding extra resistant forces to represent the track curvature and gradients. The prediction of in-train forces represents the most critical aspect in modeling the longitudinal dynamics of long trains made up of several vehicles. In fact, coupling elements have non-linear force–deflection characteristics, with different behavior in loading and unloading states, thus featuring a hysteretic loop. Look-up tables storing data from experimental tests are generally used to model these elements; however, other strategies, such as fitting curves and white-box models are witnessed in the literature. Recently, an international benchmarking of longitudinal train dynamics simulator was established in order to compare the output results obtained by different models with the same input data. The research group from Politecnico di Torino performed the simulations using the multibody software Simpack, but computational inefficiencies and numerical divergences occurred. To overcome these issues, a new dedicated in-house code was developed in the MATLAB environment. The paper focuses on the description of this new code and its validation, which was carried out by performing the simulations according to the benchmark inputs and comparing the results with the outputs from the other participants.

A Dynamic Model of Friction Draft Gear

2014 ◽  
Author(s):  
Qing Wu ◽  
Maksym Spiryagin ◽  
Colin Cole
Keyword(s):  
Dynamic Modeling ◽  
Field Test ◽  
Modeling And Prediction ◽  
Heavy Haul ◽  
Draft Gear ◽  
Train Dynamics ◽  
Simulation Results ◽  
Model Of Friction ◽  
Heavy Haul Trains ◽  
Force Displacement

Friction draft gears are the most widely used draft gears. Modeling and prediction of their dynamic behavior are of significant assistance in addressing various concerns. Longer, heavier and faster heavy haul trains mean larger in-train forces and more complicated force patterns, which require further improvements of dynamic modeling of friction draft gears to assess the longitudinal train dynamics. In this paper a force-displacement characteristics model named “base model” was described. The base model was simulated after the analyses of a set of field-test data. Approaches to improve the base model to a full advanced draft gear model were discussed; preliminary simulation results of an advanced draft gear model were also presented.

Non-Stationary Random Vibration Analysis of Railway Bridges Under Moving Heavy-Haul Trains

2018 ◽  
Vol 18 (03) ◽  
pp. 1850035 ◽  
Author(s):  
Zhihui Zhu ◽  
Lidong Wang ◽  
Zhiwu Yu ◽  
Wei Gong ◽  
Yu Bai
Keyword(s):  
Random Vibration ◽  
Vertical Acceleration ◽  
Railway Bridges ◽  
Coupling System ◽  
Ballasted Track ◽  
Heavy Haul ◽  
Train Speed ◽  
Track Irregularity ◽  
Heavy Haul Trains ◽  
Track Bridge

This paper presents a non-stationary random vibration analysis of railway bridges under moving heavy-haul trains by the pseudo-excitation method (PEM) considering the train-track-bridge coupling dynamics. The train and the ballasted track-bridge are modeled by the multibody dynamics and finite element (FE) method, respectively. Based on the linearized wheel-rail interaction model, the equations of motion of the train-ballasted track-bridge coupling system are then derived. Meanwhile, the excitations between the rails and wheels caused by the random track irregularity are transformed into a series of deterministic pseudo-harmonic excitation vectors by the PEM. Then, the random vibration responses of the coupling system are obtained using a step-by-step integration method and the maximum responses are estimated using the 3[Formula: see text] rule for the Gaussian stochastic process. The proposed method is validated by the field measurement data collected from a simply-supported girder bridge (SSB) for heavy-haul trains in China. Finally, the effects of train speed, grade of track irregularity, and train type on the random dynamic behavior of six girder bridges for heavy-haul railways are investigated. The results show that the vertical acceleration and dynamic amplification factor (DAF) of the midspan of the SSB girders are influenced significantly by the train speed and track irregularity. With the increase in the vehicle axle-load, the vertical deflection-to-span ratio ([Formula: see text]) of the girders increases approximately linearly, but the DAF and vertical acceleration fail to show clear trend.

scholarly journals Exploration of key traction-running equipment and its problems on heavy-haul trains and research on technology development

2020 ◽  
Vol 2 (3) ◽  
pp. 161-182
Author(s):  
Chunyang Chen ◽  
Wei Li ◽  
Youmei Liu ◽  
Xiang Wei
Keyword(s):  
Technology Development ◽  
Rolling Stock ◽  
Practical Applications ◽  
Technical Developments ◽  
Heavy Haul Train ◽  
Heavy Haul ◽  
Traction Equipment ◽  
Heavy Haul Trains ◽  
Technology Control ◽  
Heavy Haul Railway

Abstract In recent years, heavy-haul train technology has seen a number of innovations worldwide, and train traction-running technology has also made great progress, resulting in a rich pool of experience and a range of promising applications. This paper summarizes the key technologies of traction running in heavy-haul combined trains, especially locomotive and rolling-stock technology, traction technology, braking technology, control technology, communication technology and safety technology. At the same time, based on an analysis of practical applications, this paper further explores the main problems and urgent needs of traction equipment on heavy-haul trains. With an eye to the future, the heavy-haul railway system will develop in the direction of informatization, automation and intelligence, in order to build a greener, more energy-saving, safer and more efficient railway. This paper therefore looks forward to the technical developments of heavy-haul combined trains, and provides a reference for the development of heavy-haul railways.

Parallel Computing Enables Whole-Trip Train Dynamics Optimizations

2015 ◽  
Vol 11 (4) ◽  
Author(s):  
Qing Wu ◽  
Colin Cole ◽  
Maksym Spiryagin
Keyword(s):  
Parallel Computing ◽  
Computing Time ◽  
Computing Technique ◽  
Gear Design ◽  
Multiobjective Particle Swarm Optimization ◽  
Draft Gear ◽  
Speed Up ◽  
Train Dynamics ◽  
Dynamics Simulations ◽  
Pareto Fronts

Due to the high computing demand of whole-trip train dynamics simulations and the iterative nature of optimizations, whole-trip train dynamics optimizations using sequential computing schemes are practically impossible. This paper reports advancements in whole-trip train dynamics optimizations enabled by using the parallel computing technique. A parallel computing scheme for whole-trip train dynamics optimizations is presented and discussed. Two case studies using parallel multiobjective particle swarm optimization (pMOPSO) and parallel multiobjective genetic algorithm (pMOGA), respectively, were performed to optimize a friction draft gear design. Linear speed-up was achieved by using parallel computing to cut down the computing time from 18 months to just 11 days. Optimized results using pMOPSO and pMOGA were in agreement with each other; Pareto fronts were identified to provide technical evidence for railway manufacturers and operators.

scholarly journals Influence of Draft Gear Modeling on Dynamics Simulation for Heavy-Haul Train

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Cheng Lei ◽  
Jia Liu ◽  
Lisheng Dong ◽  
Weihua Ma
Keyword(s):  
Impact Test ◽  
Dynamics Simulation ◽  
Lookup Table ◽  
Bench Test ◽  
Spring Model ◽  
Change Rate ◽  
Heavy Haul ◽  
Draft Gear ◽  
Table Model ◽  
Simulation Results

In order to study the impedance characteristics of the frictional draft gear, MT-2 draft gear is studied, and its mechanical properties are analyzed firstly. Then, the mathematical models of two common draft gears are established based on the data collected from the vehicle impact test, and the effects of the two modeling methods on the simulation results are compared through the shunting impact test and the bench test simulation. Researches show that, under various experimental conditions, the simulated draft gear characteristic curve of the lookup table model moves along a fixed trajectory regardless of the change rate of the draft gear stroke, while simulation results of the wedge-spring model depend on the change rate of the draft gear stroke and are more consistent with the experimental results, reflecting the dynamic characteristics of the draft gear and suggesting better adaptability and wider application. Finally, the “1 + 1” grouped 20,000-ton heavy-haul combined train model is established, with its draft gear characteristics under the full-braking condition on flat straight track analyzed. Calculation results and test results of the lookup table model and the wedge-spring model are compared, indicating that using the wedge-spring model to calculate the longitudinal dynamics performance is more accurate. The influence of the modeling on the longitudinal impulse simulation of the train after air braking is also studied, revealing that the variation trends of the coupler force curves of two models are basically the same, but the amplitude and frequency of the longitudinal impulse are different.

A fast simulation approach to assess draft gear loads for heavy haul trains during braking

2021 ◽  
pp. 1-20
Author(s):  
Jony J. Eckert ◽  
Ícaro P. Teodoro ◽  
Luis H. Teixeira ◽  
Thiago S. Martins ◽  
Paulo R. G. Kurka ◽  
...  
Keyword(s):  
Simulation Approach ◽  
Fast Simulation ◽  
Heavy Haul ◽  
Draft Gear ◽  
Heavy Haul Trains

scholarly journals A review on design and testing methodologies of modern freight train draft gear system

2021 ◽  
Author(s):  
Simon Wagner ◽  
Colin Cole ◽  
Maksym Spiryagin
Keyword(s):  
Soviet Union ◽  
South America ◽  
Former Soviet Union ◽  
Rolling Stock ◽  
Freight Train ◽  
Wide Range ◽  
Draft Gear ◽  
Design And Testing ◽  
Damping Systems ◽  
The Eu

AbstractRolling stock connection systems are key to running longer and heavier trains as they provide both the connections of vehicles and the damping, providing the longitudinal suspension of the train. This paper focuses on the evolution of both connection and stiffness damping systems. Focus is on freight rolling stock, but passenger draw gears are also examined. It was found that connection systems have evolved from the buff and chain system used in the pioneer railways of the 1800s to the modern auto-coupler connection systems that are in-service worldwide today. Refined versions of the buff and chain coupling are, however, still in use in the EU, UK, South America and India. A wide range of auto-coupler systems are currently utilised, but the AAR coupler (Janney coupler) remains the most popular. A further variation that persists is the SA3 coupler (improved Wilson coupler) which is an alternative auto-coupler design used mainly throughout the former Soviet Union. Restricting the review to auto-coupler systems allowed the paper to focus on draft gears which revealed polymer, polymer-friction, steel spring-friction, hydraulic draft gears and sliding sill cushioning systems. Along with the single compressive draft gear units balanced and floating plate configurations are also presented. Typical draft gear acceptance standards are presented along with modelling that was included to aid in presentation of the functional characteristics of draft gears.

scholarly journals Recent Developments in Using Molecular Dynamics Simulation Techniques to Study Biomolecules

2017 ◽  
Vol 33 (7) ◽  
pp. 1354-1365 ◽  
Author(s):  
Liao-Ran CAO ◽  
◽  
Chun-Yu ZHANG ◽  
Ding-Lin ZHANG ◽  
Hui-Ying CHU ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Dynamics Simulation ◽  
Simulation Techniques ◽  
Recent Developments

Analysis of Brake Failure and Runaway Accidents in Mountain Terrain in Canada

2013 ◽  
Author(s):  
Daoxing Chen
Keyword(s):  
Dynamics Simulation ◽  
Contributing Factors ◽  
Friction Heat ◽  
Mountain Terrain ◽  
Maintenance Practice ◽  
Train Operation ◽  
Brake Application ◽  
Property Loss ◽  
Train Dynamics ◽  
Mountain Terrains

A number of serious rail runaway accidents have occurred in recent years on long and high grade downhill tracks in mountain terrains in Canada, causing fatal injuries and huge property loss. They were caused by brake failure, misunderstanding of brake features, maintenance deficiency and/or improper brake application on the trains. Train dynamics simulation, brake ratio testing, and dynamometer testing on friction heat fade helped disclose the causes and contributing factors in the cases presented in this paper. Guidelines were revised for safer train operation, equipment requirements and maintenance practice in the mountain terrain conditions.

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