Problems, assumptions and solutions in locomotive design, traction and operational studies

AbstractLocomotive design is a highly complex task that requires the use of systems engineering that depends upon knowledge from a range of disciplines and is strongly oriented on how to design and manage complex systems that operate under a wide range of different train operational conditions on various types of tracks. Considering that field investigation programs for locomotive operational scenarios involve high costs and cause disruption of train operations on real railway networks and given recent developments in the rollingstock compliance standards in Australia and overseas that allow the assessment of some aspects of rail vehicle behaviour through computer simulations, a great number of multidisciplinary research studies have been performed and these can contribute to further improvement of a locomotive design technique by increasing the amount of computer-based studies. This paper was focused on the presentation of the all-important key components required for locomotive studies, starting from developing a realistic locomotive design model, its validation and further applications for train studies. The integration of all engineering disciplines is achieved by means of advanced simulation approaches that can incorporate existing AC and DC locomotive designs, hybrid locomotive designs, full locomotive traction system models, rail friction processes, the application of simplified and exact wheel-rail contact theories, wheel-rail wear and rolling contact fatigue, train dynamic behaviour and in-train forces, comprehensive track infrastructure details, and the use of co-simulation and parallel computing. The co-simulation and parallel computing approaches that have been implemented on Central Queensland University’s High-Performance Computing cluster for locomotive studies will be presented. The confidence in these approaches is based on specific validation procedures that include a locomotive model acceptance procedure and field test data. The problems and limitations presented in locomotive traction studies in the way they are conducted at the present time are summarised and discussed.

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A numerical study of the influence of lateral geometry irregularities on mechanical deterioration of freight tracks

Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit ◽

10.1177/0954409712445115 ◽

2012 ◽

Vol 226 (6) ◽

pp. 575-586 ◽

Cited By ~ 13

Author(s):

Kalle Karttunen ◽

Elena Kabo ◽

Anders Ekberg

Keyword(s):

Numerical Study ◽

Contact Point ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

Field Measurements ◽

Rolling Contact ◽

Railway Track ◽

Operational Conditions ◽

Track Geometry ◽

Track Maintenance

Optimisation of railway track maintenance requires knowledge of how a deteriorated track geometry will affect subsequent loading and damage of the track. This is the scope of the current study where, in particular, the influence on track shift forces and rolling contact fatigue is investigated through numerical simulations. To this end, track geometries are obtained from field measurements. Lateral irregularities are extracted and scaled to represent different levels of geometry deterioration. Multibody simulations of dynamic train–track interaction featuring two freight wagon types are performed under different operational conditions. Track shift forces and rolling contact fatigue damage are further evaluated from simulation results. It is found that track shift forces tend to follow a normal distribution for moderate levels of lateral track geometry irregularities, and that an approximate linear relationship between standard deviations of lateral irregularities and track shift forces can be established. The relation between lateral track irregularity magnitude and rolling contact fatigue is more complex. Increasing levels of lateral irregularities will decrease the fraction of curve length affected by rolling contact fatigue for sharp curves, whereas for shallow curves it increases. As detailed in the article, this is caused by the lateral movement of the contact point as imposed by the track irregularities. Furthermore, the influence of wheel/rail friction and wear is investigated.

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18CrNiMo7-6 with TRIP-Effect for Increasing the Damage Tolerance of Gear Components — Part I: Alloy Design

Materials Science Forum ◽

10.4028/www.scientific.net/msf.783-786.633 ◽

2014 ◽

Vol 783-786 ◽

pp. 633-638

Author(s):

Margarita D. Bambach ◽

Andreas Stieben ◽

Wolfgang Bleck

Keyword(s):

High Performance ◽

Damage Tolerance ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

High Strength ◽

Residual Austenite ◽

Rolling Contact ◽

Optimum Process ◽

Trip Effect ◽

Stress Concentrations

High performance components such as gear wheels shall be resistant to rolling-contactfatigue. This type of failure is usually caused by effects occurring on a microscopic scale, such ascrack initiation at non-metallic inclusions. Much effort has been invested so far in improving thesteel cleanliness. However, these high performance components often do not reach the desiredservice life. Preliminary failure within the guarantee terms still occurs which leads to high warrantycosts. Alternative to improving steel cleanliness, the damage tolerance of high performancecomponents could be increased by inducing the TRIP-effect around the crack tip. Due to high localstrain hardening, martensite transformation occurs. The high compressive stresses related to it coulddelay or stop crack propagation by reducing stress concentrations via plastic deformation. As aresult, rolling-contact fatigue resistance of carburized steels may be increased and preliminaryfailure may be avoided. Part I of this study focuses on modifying the chemical composition ofconventional 18CrNiMo7-6 steel with Al to develop a high-strength, yet ductile matrix with a highwork hardening potential. Dilatometric tests on laboratory melts analyze the possibility of adjustinga microstructure able to produce a TRIP-effect. Both isothermal annealing and Quenching andPartitioning (Q&P) are used to stabilize residual austenite and optimum process routes areidentified.

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Observation of Crack Propagation in PEEK Polymer Bearings under Water-Lubricated Conditions

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.566.109 ◽

2012 ◽

Vol 566 ◽

pp. 109-114 ◽

Cited By ~ 7

Author(s):

Hitonobu Koike ◽

Katsuyuki Kida ◽

Takashi Honda ◽

Koshiro Mizobe ◽

Shunsuke Oyama ◽

...

Keyword(s):

Crack Propagation ◽

High Performance ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

Rolling Contact ◽

Practical Applications ◽

Performance Engineering ◽

Poly Ether Ether Ketone ◽

Laser Confocal Microscope ◽

Circular Cracks

Radial ball bearings made of metal, ceramics and plastics are commonly used as important components in various types of industrial machinery. Due to the latest markets demands for elements capable of withstanding e.g. corrosive environment, metallic bearings are being gradually replaced by components produced from high performance engineering plastic polymers. In order to investigate the failure mechanism of polymer bearings and further improve their performance in practical applications in an underwater environment, in this research crack propagation in Poly-ether-ether-ketone (PEEK) was studied by rolling contact fatigue (RCF) testing under water. Crack propagation in the inner ring raceway surface and subsurface areas of PEEK bearings after testing was observed by a laser confocal microscope. Cracks and flaking failure were found on the bearing raceway surface. From the RCF tests results, it was found that the detected cracks could be divided into three groups: Main Surface Cracks, Semi-circular Cracks and Main Subsurface Cracks. It is concluded that flaking occurs on the inner ring raceway due to the fusion of semi-circular cracks and a main subsurface crack.

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Influence of Radial Load on PEEK Plastic Bearings Life Cycle under Water Lubricated Conditions

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.217-218.1260 ◽

2011 ◽

Vol 217-218 ◽

pp. 1260-1265 ◽

Cited By ~ 10

Author(s):

Hitonobu Koike ◽

Takashi Honda ◽

Katsuyuki Kida ◽

Edson Costa Santos ◽

Justyna Rozwadowska ◽

...

Keyword(s):

Feed Rate ◽

High Performance ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

Rolling Contact ◽

Wear Loss ◽

Ball Bearings ◽

Before And After ◽

Dry Conditions ◽

Market Needs

Radial ball bearings made of metal, ceramics and plastics are commonly used as important components in industrial machinery. Usage of high performance engineering plastic polymers is increasing progressively as a replacement for metal components due to the latest markets demands. Poly-ether-ether-ketone (PEEK) is a promising material for precision-machined custom bearings, products that are expected to suit special market needs. In the present study, PEEK radial ball bearings were manufactured by lathe machining under different parameters and their rolling contact fatigue (RCF) resistance under water lubricated conditions was investigated. We observed the surface of the bearings prior and after testing by laser confocal microscope. The wear loss was measured by weighing the bearings before and after test. Cracks and/or flaking failures were identified on the bearing surface after testing. From the RCF tests results, we found that, at water lubricated conditions, crack initiation occurred later in the material that was machined at slower feed rate while at dry condition, the feed rate had little influence on the wear loss and cracking. Wear loss in the case of bearings tested under water was much less severe than that of bearings tested at dry conditions.

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Surface Densification Coupled with Higher Density Processes Targeting High-Performance Gearing

Materials Science Forum ◽

10.4028/www.scientific.net/msf.534-536.317 ◽

2007 ◽

Vol 534-536 ◽

pp. 317-320 ◽

Cited By ~ 1

Author(s):

Francis Hanejko ◽

Arthur Rawlings ◽

Patrick King ◽

George Poszmik

Keyword(s):

High Performance ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

High Strength ◽

Rolling Contact ◽

Powder Metal ◽

Surface Densification ◽

Performance Requirements ◽

Fatigue Durability ◽

Steel Grades

This paper will describe a powder and processing method that facilitates single presssingle sintered densities approaching 7.5 g/cm³. At this sintered density, mechanical properties of the powder metal (P/M) component are significantly improved over current P/M technologies and begin to approach the performance of wrought steels. High performance gears have the added requirement of rolling contact fatigue durability that is dependent upon localized density and thermal processing. Combining high density processing of engineered P/M materials with selective surface densification enables powder metal components to achieve rolling contact fatigue durability and mechanical property performance that satisfy the performance requirements of many high strength automotive transmission gears. Data will be presented that document P/M part performance in comparison to conventional wrought steel grades.

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Herstellungsprozess und Wälzfestigkeit von hybriden Hochleistungsbauteilen/Manufacturing of Hybrid High-Performance Components under Rolling Contact Fatigue

Konstruktion ◽

10.37544/0720-5953-2018-09-84 ◽

2018 ◽

Vol 70 (09) ◽

pp. 84-89

Author(s):

Maximilian Mildebrath ◽

Hans Jürgen Maier ◽

Thomas Hassel ◽

Timm Coors ◽

Florian Pape ◽

...

Keyword(s):

Material Properties ◽

High Performance ◽

Materials Science ◽

Steel Substrate ◽

Construction Material ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

Industrial Applications ◽

Rolling Contact ◽

Tailored Forming

Inhalt: Moderne Massivbauteile werden herkömmlich aus Monomaterialien gefertigt. Viele Bauteile besitzen dabei Funktions- und Strukturbereiche, welche durch unterschiedliche Beanspruchungsprofile sehr unterschiedliche Anforderungen an den Konstruktionswerkstoff stellen. Somit ermöglicht das eingesetzte Material oft nur einen Kompromiss hinsichtlich der geforderten Materialeigenschaften und der Leistungsfähigkeit des Bauteils. Im Sonderforschungsbereich 1153 „Tailored Forming“ an der Leibniz Universität Hannover (LUH) werden neue Prozessketten zur Realisierung hoch belastbarer hybrider Massivbauteile entwickelt. In Zusammenarbeit des Instituts für Werkstoffkunde (IW) und des Instituts für Maschinenkonstruktion und Tribologie (IMKT) wurden hybride Lagerscheiben zum Einsatz als Axial-Zylinderrollenlagern entwickelt. Diese wurden mittels Plasma-Pulver-Auftragschweißen (PPA) aus Vergütungsstahl hergestellt (Bild 1) und anschließend bezüglich Ihrer Wälzfestigkeit untersucht. Diese Untersuchungen dienen als Grundlage zur Evaluierung von Leistungsfähigkeit und Qualität des Beschichtungsprozesses sowie der Materialeigenschaften. Mit ersten hybrid hergestellten Rohlingen werden Maschinenelemente gefertigt, um die Eignung des Prozesses für industrielle Anwendungen zu bewerten.   Abstract: Modern solid components are conventionally manufactured from monomaterials. Many components are equipped with functional and structural areas, which have to fulfil various demands regarding the construction material due to different stress profiles. Thus, the applied material offers a trade-off concerning the required material properties and the performance of the component. The Collaborative Research Center 1153 „Tailored Forming“ at Leibniz Universität Hannover (LUH) is developing new process chains for the realization of highly resilient hybrid solid components. In cooperation with the Institute of Materials Science (IW) and the Institute of Machine Design and Tribology (IMKT), multi-material bearing discs were developed for use as cylindrical roller thrust bearings. These were produced by plasma powder deposition welding (PPA) from heat treatable steel (Figure 1) on a steel substrate and then tested under rolling contact loads. These investigations serve as a basis for evaluating the performance and quality of the coating process as well as the material properties. In this publication, the above concept was proven for first hybrid produced workpieces in order to assess the suitability of the process for industrial applications.

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