Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-18699 Beitrag zu einem Tagungsband Österle, Werner; Müller, Urs; Desplanques, Y.; Bulthé, A.-L.; Degallaix, G.; Dmitriev, A.I. 3rd Body formation of two different brake pad materials designed for railway application 2006 5th European Conference on Braking (JEF 2006), November 8-9, 2006, Lille, France (Proceedings) 5th European Conference on Braking (JEF 2006) Lille, France 2006-11-08 2006-11-09 107 115 2016-02-19 OPUS4-38545 Zeitschriftenartikel Dmitriev, A. I.; Österle, Werner; Kloß, Heinz; Orts-Gil, Guillermo A study of third body behaviour under dry sliding conditions. Comparison of nanoscale modelling with experiment Automotive brake pads consist of many components but it is still not entirely clear which role each of the elements of this complex composition plays to provide the specified regimes of sliding. This is due to the mutual interaction of multiscale mechanisms, realized during the friction. In this work we have attempted to partly answer this question using computer simulations. Since the simulation allows us to consider various combinations of the structure of the system being simulated ceteris paribus, it becomes possible to understand the role of each constituent sequentially. The main attention is paid to the structure and composition of the thin film that forms on the surface of both bodies as a result of compaction of the wear product, its chemical composition and oxidation. This layer, also named a third body or friction film, differs in composition and microstructure from the two first bodies. We considered a single contact for the steady state sliding when the structure and composition of friction films already are formed. As a modelling tool we used the method of movable cellular automata, which has well proven itself in solving of such tasks. We investigated the influence of modification of the structure and composition of the third body on the features of system behaviour at friction. To assess the adequacy of the numerical model, experimental studies with an artificial third body were also carried out. The Simulation results are in good agreement with experimental data. 2012 Estonian Journal of Engineering 18 3 270 278 10.3176/eng.2012.3.12 2016-12-02 OPUS4-52534 Zeitschriftenartikel Khimich, M. A.; Prosolov, K. A.; Mishurova, Tatiana; Evsevleev, Sergei; Monforte, X.; Teuschl, A. H.; Slezak, P.; Ibragimov, E. A.; Saprykin, A. A.; Kovalevskaya, Z. G.; Dmitriev, A. I.; Bruno, Giovanni; Sharkeev, Y. P. Advances in Laser Additive Manufacturing of Ti-Nb Alloys: From Nanostructured Powders to Bulk Objects The additive manufacturing of low elastic modulus alloys that have a certain level of porosity for biomedical needs is a growing area of research. Here, we show the results of manufacturing of porous and dense samples by a laser powder bed fusion (LPBF) of Ti-Nb alloy, using two distinctive fusion strategies. The nanostructured Ti-Nb alloy powders were produced by mechanical alloying and have a nanostructured state with nanosized grains up to 90 nm. The manufactured porous samples have pronounced open porosity and advanced roughness, contrary to dense samples with a relatively smooth surface profile. The structure of both types of samples after LPBF is formed by uniaxial grains having micro- and nanosized features. The inner structure of the porous samples is comprised of an open interconnected system of pores. The volume fraction of isolated porosity is 2 vol. % and the total porosity is 20 vol. %. Cell viability was assessed in vitro for 3 and 7 days using the MG63 cell line. With longer culture periods, cells showed an increased cell density over the entire surface of a porous Ti-Nb sample. Both types of samples are not cytotoxic and could be used for further in vivo studies. MDPI 2021 Nanomaterials 11 5 1159 urn:nbn:de:kobv:b43-525344 10.3390/nano11051159 https://creativecommons.org/licenses/by/4.0/deed.de 2021-04-29 OPUS4-18701 Beitrag zu einem Tagungsband Österle, Werner; Dmitriev, A.I.; Kloß, Heinz Jayashree Bijwe, Basic considerations for the development of friction materials Delhi, India Indian Academy of Sciences 2008 Proceedings of the IWAAFC-2, International Workshop on Advances in Asbestos-free Friction Composites IWAAFC-2, International Workshop on Advances in Asbestos-free Friction Composites Delhi, India 2008-02-07 2008-02-08 24 51 2016-02-19 OPUS4-18700 Beitrag zu einem Tagungsband Österle, Werner; Dmitriev, A.I.; Urban, Ingrid Jayashree Bijwe, Characterization of up to date brake friction materials Delhi, India Indian Institute of Technology 2006 IWAAFC-1, International Workshop on Advances in Asbestos free Friction Composites, January 5-6, 2006, Delhi, India (Proceedings) IWAAFC-1, International Workshop on Advances in Asbestos free Friction Composites Delhi, India 2006-01-05 2006-01-06 21 35 2016-02-19 OPUS4-18698 Zeitschriftenartikel Dmitriev, A.I.; Smolin, A.Y.; Psakhie, S.G.; Österle, Werner; Kloß, Heinz; Popov, V.L. Computer modeling of local tribological contacts by the example of the automotive brake friction pair In the paper the method of discrete modeling (movable cellular automata method) and combined discrete-continuous description of the simulated medium are used to analyze processes occurring in the local contact of the automotive brake system. The characteristic size of the considered region is 1.5 ?m. The following contact situation is simulated: steel fiber coated by an iron oxide film as the brake pad and pearlitic steel also coated by an iron oxide layer as the disc. On the assumption of oxide layer wearing we simulate the iron oxide - iron oxide, iron oxide - metal and metal - metal contacts. The calculation results for the friction coefficient for various contact situations give quite adequate values. For example, for the oxide - oxide system the calculated coefficient is approximately equal to 0.4, while for the metal - metal contact the obtained value varies from 0.7 to 0.9. Analysis of a set of the obtained results allows concluding that oxide is formed more rapidly than the sliding layer, which in turn makes the friction coefficient value stabilized. Tomsk Inst. of Strength Physics and Materials Science SB RAS 2008 Physical mesomechanics 11 1-2 73 84 10.1016/j.physme.2008.03.008 2016-02-19 OPUS4-26822 Zeitschriftenartikel Österle, Werner; Dmitriev, A.I.; Kloß, Heinz Does ultra-mild wear play any role for dry friction applications, such as automotive braking? Nanostructured third body films and/or storage of wear debris at the surfaces of the first bodies are deemed as prerequisites of sliding under ultra-mild wear conditions. Since such features have been observed experimentally on brake pads and discs, attempts were undertaken to study their sliding behaviour by modelling on the nanoscopic scale with an approach based on Movable Cellular Automata (MCA). The model rendered the possibility to study the influence of different nanostructures systematically and to assess the impact of different brake pad ingredients on the sliding behaviour, velocity accommodation and friction force stabilization at a sliding contact. Besides providing a review on previously published modelling results, some additional new graphs enabling better visualization of dynamic processes are presented. Although ultra-mild wear conditions were considered to be essential for achieving the desired tribological properties, transitions to mesoscopic and macroscopic wear mechanisms were studied as well. The final conclusion is that ultra-mild wear and corresponding smooth sliding behaviour play an important role during automotive braking, even though temporarily and locally events of severe wear may cause friction instabilities, surface damage and release of coarse wear particles. Cambridge [u.a.] Soc. 2012 Faraday discussions 156 0 159 171 10.1039/c2fd00117a 2016-02-19 OPUS4-33035 Zeitschriftenartikel Österle, Werner; Dmitriev, A.I.; Gradt, Thomas; Häusler, Ines; Hammouri, Basem; Morales Guzman, Pablo Israel; Wetzel, B.; Yigit, D.; Zhang, G. Exploring the beneficial role of tribofilms formed from an epoxy-based hybrid nanocomposite The composition and nanostructure of a beneficial tribofilm formed during sliding of a hybrid nanocomposite against steel were characterized comprehensively. A similar nanostructure was produced by high energy ball milling of the three identified tribofilm constituents: silica, hematite and graphite. By supplying powders to a pin-on-disc test it has been shown that neither silica, nor hematite, nor a mixture of both provide the low coefficient of friction (COF) observed for the hybrid composite. Only if graphite was blended with the oxides, the low COF was obtained. Thus, a film of finely dispersed stable inorganic wear products containing 15 vol% graphite provides low friction and wear in the considered case. Oxford Butterworth-Heinemann 2015 Tribology International 88 126 134 10.1016/j.triboint.2015.03.006 2016-02-20 OPUS4-33421 Zeitschriftenartikel Österle, Werner; Giovannozzi, A.; Gradt, Thomas; Häusler, Ines; Rossi, A.; Wetzel, B.; Zhang, G.; Dmitriev, A.I. Exploring the potential of Raman spectroscopy for the identification of silicone oil residue and wear scar characterization for the assessment of tribofilm functionality We applied a combination of Raman spectroscopy (RS) and cross-sectional transmission electron microscopy (X-TEM) to identify silicone oil residues and tribofilms at steel disc surfaces after tribological testing. Neither chemical cleaning nor mechanical removal of a 50 µm thick surface layer produced a surface without any silicone residue. Nevertheless, long-term tribological properties are not affected due to silicone degradation which has been proved by Raman spectroscopy. Excellent anti-wear and anti-friction properties of a nanocomposite at severe stressing conditions correlated with the formation of a silica-based tribofilm containing amorphous and graphite-like carbon nanoparticles. Since reliable carbon quantification by analytical TEM is difficult, RS is a useful complementary method for carbon identification at wear scars. Oxford Butterworth-Heinemann 2015 Tribology International 90 481 490 10.1016/j.triboint.2015.04.046 2016-02-20 OPUS4-35040 Beitrag zu einem Tagungsband Dmitriev, A.I.; Kloß, Heinz; Österle, Werner Final outcome of a fundamental research project on tribofilms formed during automotive braking, Part 2: Numerical simulation In part 1 it was shown that tribofilms usually are 100 nm thick and exhibit a multiphase nanocrystalline structure. The objective of our modelling efforts was to obtain a better understanding of the sliding behaviour and associated friction properties and to study the impact of internal and external parameters on these properties. The method of movable cellular automata (MCA) was used. The third bodies were considered as aggregates of linked nanoparticles which may decompose and form a layer of granulär material, the so-called mechanically mixed layer (MML), if certain fracture criteria are fulfilled. The basic model structure which consists of Fe3Ü4 nanoparticles with 13 % graphite inclusions was used. In order to assess the robustness of the model the following parameter studies were performed. The pressure ränge at an asperity contact was varied between 15 and 50 MPa. The mechanical properties of the oxide were varied between brittle and ductile behaviour corresponding to room temperature and high temperature behaviour. The mechanical properties of the soft ingredient were varied + 50 % of the properties of graphite. The influence London FISITA International Federation of Automotive Engineering Societies 2014 EuroBrake 2014 (Proceedings) 978-0-9572076-4-6 EuroBrake 2014 Lille, France 13.05.2014 15.05.2014 1 9 2016-02-20