Istraživanje nosivosti klizno-valjnih parova

scientific master's theses

• Title (english): Load carrying capacity research of sliding/rolling pairs
• Author: Dragan Žeželj
• Mentor: Milan Opalić (mentor)
• Committee member: Ivo Alfirević (predsjednik povjerenstva)
• Committee member: Milan Opalić (član povjerenstva)
• Committee member: Jože Flašker (član povjerenstva); VIAF: 66191048
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2002-11-19, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering
• Universal decimal classification (UDC): 621 - Mechanical engineering. Nuclear technology. Machinery

Abstract

Istraživanje u ovom radu odnosi se na područje temeljnih elemenata strojeva, poglavito nosivost podmazivanih klizno-valjnih parova. Pojam klizno-valjnog para odnosi se na dva opterećena elementa čije se površine ili dijelovi površina dodiruju sa ili bez prisustva maziva, te se međusobno relativno gibaju uz određeni odnos klizanja i valjanja. U uvodnom dijelu rada predstavljene su teorijske osnove dodira dvaju krutih tijela, te su sistematizirani tipovi kontakata i njima svojstveni tipovi oštećenja. Rupičenje i zaribavanje posebno su izdvojeni kao češći oblici trošenja kod klizno-valjnih parova. Sistematski su obrađene tri relevantne teorije podmazivanog dodira: hidrodinamička (HD), kojom je obrađen dodir dvaju idealno krutih tijela u prisustvu maziva za koje se uzima da ima karakteristike \Newtonovog fluida (\Newtonovo mazivo), te u izotermičkim uvjetima, elastohidrodinamička (EHD), kojom je obrađen dodir dvaju elastičnih tijela u prisustvu maziva čiji viskozitet zavisi o tlaku, te u izotermičkim uvjetima, termoelastohidrodinamička (TEHD), kojom su uz uvjete EHD teorije uključeni i utjecaji vezani uz promjenu temperature. Za svaku od navedenih teorija dana je uvodna analiza, te obrađeno područje primjene na jednodijelni klizni radijalni ležaj. U sklopu razmatranja EHD teorije, pored razrade za Newtonovo, obrađen je i slučaj ne-Newtonovog maziva, te je dat pregled češće korištenih reoloških modela kojima se opisuje veza između smičnog naprezanja i brzine smične deformacije. Rezultati primjene pojedine teorije predočeni su dijagramima za svaki relevantni čimbenik.

Abstract (english)

Research presented in this work deals with basic machine elements, especially with load carrying capacity of lubricated pairs with sliding and rolling motion involved. Such pair could be described as couple of loaded elements contacting over common surface in presence or without lubricant, in relative motion with some ratio of sliding and rolling. Introduction gives theoretical basics for rigid bodies contact, systematisation of such contacts and corresponding damages that usually occur. Two models of wear, pitting and scuffing, are outlined as commonly found at pairs mentioned. Three theories of lubricated contact are studied and presented: Hydrodynamic (HD), that deals with contact between two ideally rigid bodies in presence of Newtonian lubricant in isothermal environment, Elastohydrodynamic (EHD), that deals with elastic bodies, Newtonian or non-Newtonian lubricant whose viscosity depends on pressure and isothermal environment, Termoelastohydrodynamic (TEHD), for equal conditions as EHD but widen for thermal influence. Analysis was conducted for each theory mentioned, as well as study and appliance on simple journal bearing. In part of EHD study mostly used rheological models for non- Newtonian lubricants are shown. Results for each theory and corresponding factors of influence are presented in diagram form.

• Keywords: klizno-valjni parovi; kontaktno naprezanje; viskozitet; podmazivanje
• Keywords (english): sliding-rolling pairs; contact stress; viscosity; lubrication
• Language: croatian
• URN:NBN: urn:nbn:hr:235:711870
• Study programme: Title: Mechanical Engineering - mr.sc.; Study programme type: university; Study level: postgraduate; Academic / professional title: magistar znanosti (magistar znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-02-01 12:45:10