Papers by Keyword: Tribology

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Authors: Daniel Trauth, Michael Terhorst, Patrick Mattfeld, Fritz Klocke
Abstract: Machine hammer peening is an incremental forming process for high frequency surface finishing of technical components. Recently, machine hammer peening has attracted automotive industry’s attention for the surface finishing and structuring of deep drawing tools. Deep drawing tools surface structured by machine hammer peening are characterized by beneficial friction and wear characteristics in lubricated sliding contacts. However, the physics of hydrodynamic effects in machine hammer peened structures is yet insufficiently researched. Therefore, this work investigates the hydrodynamic effects in surface structures generated by machine hammer peening using a two-dimensional computational fluid dynamic analysis. The effects of structure geometry, structure arrangement and selected sliding parameters on the hydrodynamic fluid pressure and velocity distribution within the structures are analysed. It was observed, that the sliding direction and the structure arrangement have a significant influence on the hydrodynamic fluid pressure maximum.
Authors: Stephen Wan
Abstract: The aim of this paper is to introduce, in broad strokes, a framework – constructed from a fusion of granular flow (GFD) dynamics, tribology and computational fluid dynamic (CFD) techniques – for the practical analysis of mass finishing processes. The presentation opens with a short introduction to typical mass finishing processes, followed by a brief discussion on their respective correspondences to GFD regimes, and ends which some illustrative results arising from the application of this framework to vibratory finishing, which is perhaps the most industrially pervasive mass finishing process.
Authors: Aghasi R. Torosyan, Jonathan R. Tuck, Alexander M. Korsunsky, Svetlana A. Barseghyan
Authors: João Telésforo Nóbrega Medeiros, Luís Gallego Martinez, Roberto M. Souza, D.K. Tanaka
Authors: Pieter Samyn, Jan Quintelier, Wim van Paepegem, Wim De Waele
Abstract: The tribological behaviour of a polymer composite is compared during small-scale and large-scale sliding tests and it is observed that test results strongly depend on the fibre orientation and test configuration. Different wear mechanisms are evaluated by optical microscopy and finite element modelling in relation to a real application of polyester/polyester discs as bearing elements.
Authors: Zhi Wei Wang, Mei Wei Chen, Jian Wei Wu, Hai Hui Zheng, Xiao Feng Zheng
Abstract: Surface texture of tribological interfaces has the potential to improve friction and lubrication performance of various mechanical components. This review paper emphasizes on the current status of the research of surface texture, including the features, the effects on tribological performance, the forming techniques, and the modeling and simulation of surface texture. It is intended to help readers to gain a more comprehensive view on surface texture of tribological interfaces.
Authors: Phongphat Laothanasakul, Karuna Tujinda, Sirinthorn Thongsang
Abstract: In this work, the properties of frictional materials for motorcycle clutch with fly ash replacements of some original substances were studied aiming to reduce the raw materials cost. The fly ash was obtained from the domestic BLCP power plant in Rayong, Thailand. Two replacement schemes were studied;1) all of the original ingredients comprising the clutch was replaced with 15-35 %wt. fly ash and 2) only the original ingredients with similar physical and chemical properties were replaced with 40-55 %wt. fly ash. The mechanical properties, the friction coefficient and the wear performance were then studied. In addition, micro-structural characterizations of the contact surface and the wear debris were carried out. It was found that the fly ash replacement to a certain level increased the hardness resulting in a decrease in the surface wear. The specimens with fly ash replacement were found to have smoother surface leading to a lower static friction coefficient. The dynamic friction coefficient was altered according to the wear debris characteristics. The prototypes with the optimum amount of fly ash, i.e. giving minimum cost with superior or similar properties to the original product, for each scheme was produced and tested on a dynamometer. The prototypes for the 1st and 2nd schemes were found to offer the reduction in the wear rates of approx. 22 to 56% with a reduction in the cost of raw materials of approx. 15 and 23%, respectively. Severe damage of the prototypes was observed slightly sooner than that found for the original product.
Authors: Jeng Haur Horng, Jen Fin Lin, Shin Yuh Chern, Chin Chung Wei, Chun Yueh Chen
Abstract: With the rapid development of microelectromechanical systems (MEMS) technology, materials such as silicon, metal, and polymers are widely used in the MEMS field. One of the reliability concerns related to Si MEMS is unwanted wear and adhesion. Therefore, SiC film is a possible choice for surfaces because of its favorable friction and wear properties such as used in cutting tool and transmission system of wind turbine. In this study, biocompatible SAM film (ODS) was used to decrease the adhesion force and the friction coefficient of SiC surface. Experimental results show that ODS can increase the contact angle and decrease the surface roughness value of SiC surfaces for the different roughness values and roughness directions. For Si, SiC film and SAMs film on surfaces, larger normal forces lead to smaller friction coefficients and cross roughness pattern have a smaller friction coefficient than that of straight roughness pattern. In addition, ODS film can decrease the friction coefficient on cross topography with relative small roughness value more effectively than can straight topography of SiC surfaces.
Authors: Esmeray Üstünyagiz, Mohd Hafis Sulaiman, Peter Christiansen, Chris Valentin Nielsen, Niels Bay
Abstract: The trend in metal forming tribology is to develop new tribo-systems including new lubricants, tool materials and tool coatings in order to substitute environmentally hazardous lubricants by environmentally friendly tribo-systems. In preliminary testing the limits of lubrication of new tribo-systems for sheet forming production, it is advantageous to use dedicated simulative tribo-tests. This paper studies the influence of tool coatings on deep drawing operations using the Bending Under Tension (BUT) test and also under more severe tribological conditions by adopting the Strip Reduction Test (SRT) to replicate industrial ironing of deep drawn, stainless steel parts. Non-hazardous tribo-systems in form of a double layer Diamond-like coated tool applied under dry condition or with an environmentally friendly lubricant were investigated via emulating industrial process conditions in laboratory tests. Experiments revealed that the double layer coating worked successfully, i.e. with no sign of galling, when it was used with environmentally friendly lubricants, whereas the results were more prone to galling under dry condition.
Authors: A.J.A. Winnubst, S. Ran, K.W. Wiratha, D.H.A. Blank, H.R. Pasaribu, J.-W. Sloetjes, D.J. Schipper
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