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Title:Življenjska doba zavornih diskov tirnih vozil pri termomehanskem obremenjevanju
Authors:ID Šamec, Blaž (Author)
ID Potrč, Iztok (Mentor) More about this mentor... New window
ID Šraml, Matjaž (Comentor)
Files:.pdf DR_Samec_Blaz_2011.pdf (10,52 MB)
MD5: 69A7EDDB79A1AC0ED2BF7637E7C869FC
PID: 20.500.12556/dkum/52fe8f80-c4cb-401c-b39b-5be1b4f573e0
 
Language:Slovenian
Work type:Dissertation
Organization:FS - Faculty of Mechanical Engineering
Abstract: V predloženi doktorski disertaciji je razvit model za določitev življenjske dobe zavornih diskov tirnih vozil. Model temelji na predpostavki, da natančno poznamo hitrostni in višinski profil proge, na kateri bodo le-ti obratovali. Posledično to omogoča napovedovanje ciklov termomehanskega obremenjevanja, ki so vhodni podatek za določitev življenjske dobe zavornih diskov. Na osnovi zahtev računskih modelov za izračun življenjske dobe po deformacijski metodi je bila v sklopu doktorske naloge opravljena podrobna analiza materialnih lastnosti nodularne litine EN-GJS-500-7. Trdnostne lastnosti litine so bile analizirane z nateznimi preskusi pri sobni temperaturi (ST), 300 °C, 350 °C in 400 °C. Malo-ciklični preskusi utrujanja so bili izvedeni pri ST, 300 °C in 400 °C, za te temperature so bili določeni malo-ciklični parametri, ki so potrebni za izračun življenjske dobe, in izrisane deformacijske krivulje zdržljivosti. Ugotovljeno je bilo, da povišana temperatura močno vpliva na življenjsko dobo analizirane nodularne litine. S pomočjo numerične analize po metodi končnih elementov so bila analizirana napetostna in deformacijska polja, ki nastanejo med zaviranjem na dejanskem zavornem disku ter določeno kritično mesto konstrukcije le-tega. Na podlagi numeričnih rezultatov je bila z deformacijsko metodo izračunana življenjska doba zavornega diska v različnih obremenitvenih primerih za nov in obrabljen disk, pri čemer so bile ugotovljene dokaj velike razlike med posameznimi hipotezami, ki upoštevajo večosno napetostno stanje. Na koncu je podana še metodologija določitve življenjske dobe zavornih diskov pri vožnji na določeni progi oziroma hitrostnem sistemu.
Keywords:zavorni diski tirnih vozil, življenjska doba, termomehansko utrujanje, malo-ciklično utrujanje, parametri utrujanja, deformacijska metoda, metoda končnih elementov
Place of publishing:[Maribor
Publisher:B. Šamec]
Year of publishing:2011
PID:20.500.12556/DKUM-19485 New window
UDC:629.3.018.4-52(043.3)
COBISS.SI-ID:257228032 New window
NUK URN:URN:SI:UM:DK:0QWGVXBO
Publication date in DKUM:29.07.2011
Views:3511
Downloads:308
Metadata:XML DC-XML DC-RDF
Categories:KTFMB - FS
:
ŠAMEC, Blaž, 2011, Življenjska doba zavornih diskov tirnih vozil pri termomehanskem obremenjevanju [online]. Doctoral dissertation. Maribor : B. Šamec. [Accessed 23 January 2025]. Retrieved from: https://dk.um.si/IzpisGradiva.php?lang=eng&id=19485
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Secondary language

Language:English
Title:Service life of railway brake discs under thermomechanical loading
Abstract: A model for assessment of service life of railway brake disc is presented in this doctoral thesis. The model is based on the assumption that the particular railway route where brake disc will operate is precisely known. Consequently this allows prediction of thermomechanical cycles of loading, which are the input data for determination of service life for a railway brake disc. Based on the requirements of computational models for fatigue life assessment, detailed analysis of material properties of ductile cast iron EN-GJS-500-7 was done. Strength properties of cast iron were examined by tensile tests at room temperature (RT), 300 °C, 350 °C and 400 °C, while low-cycle fatigue (LCF) tests were carried out at RT, 300 °C and 400 °C. Strain-life curves were obtained and LCF parameters were determined for these temperatures. It was found out that the fatigue life of analyzed ductile cast iron is strongly affected by the increased temperature. Stress and strain fields generated during braking on the actual brake disc were analyzed with finite element method and a critical area of brake disc design has been determined. Based on numerical results, fatigue life was calculated for new and worn disc in different braking regimes, where relatively large differences between the various hypotheses that take account of multiaxial stress state were found. In the end, methodology for determining fatigue life of brake discs while driving on a particular route is presented.
Keywords:railway brake discs, service life, thermomechanical fatigue, low cycle fatigue, fatigue parameters, strain method, finite element method


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