Eckart Uhlmann; Mykola Bobyr; Yuriy Borodiy; Pavlo Lypovka; Pavel Protsenko; Janis Thalau
Abstract
As societies have a rising demand regarding mobility as well as an increasing ecological awareness, the energy efficiency, noise emissions and availability of transportation in urban environments become essential for growing cities. In this context, the role of rail-bound traffic in urban environments ...
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As societies have a rising demand regarding mobility as well as an increasing ecological awareness, the energy efficiency, noise emissions and availability of transportation in urban environments become essential for growing cities. In this context, the role of rail-bound traffic in urban environments as well as in intercity-connections is of rising importance. To guarantee travelling comfort and safety, shorter downtimes as well as power efficiency, the condition of the railway network is subject to rising quality requirements. Therefore, the maintenance, repair and overhaul as well as the material quality of railway-tracks is faced with new challenges. An important part of track maintenance is track grinding. To ensure an economically reasonable track life cycle and to prolong the time period between repair tasks, grinding processes should not induce damage such as cracks and hardening. On the other side, high productivity of track grinding, which tends to induce damage, is crucial to reduce disruptions and delays from repair. Research work presented in this paper aims at reducing the lack of knowledge concerning interactions between the track grinding parameters, grinding tool specifications and the topology of the track’s surface and damage of the track’s sub surface. Industrial track grinding processes were tested under laboratory conditions with a variation of the grinding wheel circumferential speed and depth of cut. Afterwards the ground tracks specimens were evaluated with regard to the achieved surface roughness as well as the micro-hardening, induced cracks and residual stresses in the sub surface zone. Furthermore, the influence of different external factors such as environmental conditions on the results of track grinding is analysed by evaluating the influence of the track’s initial temperature on the process results. As a result, the main influencing factors on the surface quality and the sub surface damage in track grinding were identified and their influence on the tribological behaviour of the ground tracks in contact with an opposing steel disc was analysed. Based on these considerations, recommendations on eligible track grinding strategies, which lead to highly productive yet low-damage track repair, are derived.
Balakrishnan G; Elangovan T; Shin-Sung Yoo; Dae-Eun- Kim; Kuppusami P; Venkatesh Babu R; Sastikumar D; Jung il Song
Abstract
Nanostructured single layer aluminium oxide (Al2O3), single layer zirconium oxide (ZrO2) and the (Al2O3/ZrO2) nano multilayer films were deposited on Si (100) substrates at an optimized oxygen pressure of 3×10 -2 mbar at room temperature by pulsed laser deposition. The Al2O3 layer was kept constant ...
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Nanostructured single layer aluminium oxide (Al2O3), single layer zirconium oxide (ZrO2) and the (Al2O3/ZrO2) nano multilayer films were deposited on Si (100) substrates at an optimized oxygen pressure of 3×10 -2 mbar at room temperature by pulsed laser deposition. The Al2O3 layer was kept constant at 5 nm, while ZrO2 layer thickness was varied from 5 nm to 20 nm. The X-ray diffraction (XRD) studies of single layer of Al2O3 film indicated the cubic γ-Al2O3, while the single layer of ZrO2 indicated both the monoclinic and tetragonal phases. The Al2O3/ZrO2 multilayer films of 5/5 nm and 5/10 nm indicated the tetragonal phase of ZrO2 with nanocrystalline nature. The FESEM and AFM studies showed the dense and smooth morphology of the films. The pin-on disc revealed that the 5/10 nm multilayer film has low friction coefficient ~ 0.10. The wear rate of multilayers film is half of the wear rate of the single layer films and 5/10 nm multilayer film showed a reduced wear rate when it is compared to other single and multilayers. The Al2O3-ZrO2 ceramics find wide applications in wear and corrosion resistance components, high temperature applications and bio-implant materials.
Ram Krishna Upadhyay; Lakshmi Annamalai Kumaraswamidhas
Abstract
Tribological study includes surface interaction and mechanism involve between contacts. At contact points, surface forces affect the geometry and properties of material whereas stress concentration affects processes that involve during friction interactions. Nanomechanical behaviour of thin-film and ...
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Tribological study includes surface interaction and mechanism involve between contacts. At contact points, surface forces affect the geometry and properties of material whereas stress concentration affects processes that involve during friction interactions. Nanomechanical behaviour of thin-film and surfaces has been largely studied during past years in the field of electronics industry such as microelectronics, optoelectronics application, aerospace industry, iron and steel industries and also adapted in the field of biological sector that likely to grow in near future extensively. High resolution microscope and computational techniques enable the material to investigate their interfacial problems at nanoscale. In this, we studied mechanism of tribology, with different deposition technique and their mechanical properties.
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