13343 KB214 KB0 KB2018Boltežar, MihaTurel, AlešXXVI, 118 str., 30 cmCOBISSID:16126747URN:URN:NBN:SI:doc-YA2QPP4LslA. Turelvisokošolska delaabsolute nodal coordinate formulationalternatorska krtačkabaker-grafitna krtačkacontactcopper-graphite brushdinamikadinamika sistemov telesdisertacijedissertationseksperimentexperimentkontaktmetoda absolutnih vozliščnih koordinatmultibody system dynamicsobrabatemperaturatemperaturewearČasovno spremenljiv kontaktni razvoj v dinamiki sistema togih teles| doktorsko delo|The research presents an approach to solving multibody systems dynamics of rigid and flexible bodies using the method of absolute nodal coordinates formulation and by including the detection of several simultaneous contact situations. This work experimentally researches the rotational speed, electric current and the temperature dependent material properties of copper-graphite brush. The effect of brush temperature on material properties was analised by brush dynamics through measured damping ratio. Experimentally defined brush material properties were implemented in the dynamic model of the brush, brush holder and slip ring. The dynamic model confirmed the time variability of contact situations, which was detected in the measurements of contact resistance. Experimentally, was found that, due to the change in the material properties of the brushes in a narrow temperature range between 80°C and 90°C, the damping ratio increased by 15% and the wear rate increased up to a five-foldRaziskava predstavi pristop k reševanju dinamskih sistemov togih in prožnih teles, z uporabo metode absolutnih vozliščnih koordinat ter z vključitvijo zaznavanja več sočasnih kontaktnih situacij. Za primer baker-grafitne krtačke je predstavljena študija, ki eksperimentalno povezuje predvsem od vrtljajev, električnega toka in temperature odvisne materialne lastnosti. Vpliv temperature na lastno dinamiko krtačke je bil analiziran z izmerjenim razmernikom dušenja. Izmerjene materialne lastnosti so bile implementirane v dinamski model sklopa krtačke, nosilca krtačk in drsnega obročka. Z dinamskim modelom je bila potrjena časovna spremenljivost kontaktnih situacij, ki je bila zaznana pri meritvah kontaktnih upornosti. Eksperimentalno je bilo ugotovljeno, da se zaradi spremembe materialnih lastnosti krtačk v ozkem temperaturnem območju med 80°C in 90°C nenadoma poveča razmernik dušenja za 15% ter obraba za pet kratTEXTvisokošolska delatheses and dissertationsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Ljubljani, Fakulteta za strojništvo