Thermal analysis of polymer containing tribological contacts

Siddiqui, Muhammad Shoaib Naseem (author), Kalin, Mitjan (mentor), Golobič, Iztok (comentor)

This doctoral thesis investigates the thermal behaviour of polymer-containing tribological contacts, emphasizing the role of contact temperature in governing the friction and wear performance. Initially, a comprehensive experimental study was conducted on polymer/steel pin-on-disc sliding contacts under severe operating conditions, with a special focus on the effect of steel disc thickness—acting as a heat sink—on contact temperature, friction, and wear. The findings identified the key parameters influencing the contact temperature and demonstrated its critical role in determining the tribological performance of these systems, underscoring the importance of effective thermal management in such sliding contacts. Based on these findings, predictive, ready-to-use models were developed to estimate the maximum contact temperature in both (1) polymer/steel and (2) polymer/polymer pin-on-disc sliding configurations, covering a broad spectrum of material properties, contact geometries, and loading conditions. The developed models provide an important advancement in our understanding of the contact-temperature contributions in pin-on-disc experiments by employing several new modelling approaches. In particular, the models consider an energy balance for the whole tribological system of contacting bodies, and accounts for the dissipation of frictional heat by various dissipation modes: due to the convection, conduction and radiation. The ready-to-use model for polymer/steel contacts deliver highly accurate contact temperature predictions within the validated experimental range, with an uncertainty of approximately 3%. Similarly, the model developed for polymer/polymer sliding contacts demonstrated strong alignment between predicted and measured values under the specific contact conditions explored in this study, with a relative uncertainty of about 5%. This research not only enhances the understanding of thermal and tribological interactions in polymer-based sliding contacts but also provides practical modelling tools to aid in the design, optimization, and thermal management of polymer-containing tribological systems.

• Language: English
• Keywords: contact temperature, wear mechanisms, polymers, friction, finite element modelling
• Work type: Doctoral dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: FS - Faculty of Mechanical Engineering
• Year: 2025
• Number of pages: XXX, 135 str.
• PID: 20.500.12556/RUL-174326
• UDC: 536.5:539.92:678.7(043.3)
• COBISS.SI-ID: 251892483
• Publication date in RUL: 01.10.2025

Secondary language

• Language: Slovenian
• Title: Termična analiza triboloških kontaktov s polimeri

Abstract

Doktorska disertacija preučuje toplotno obnašanje triboloških kontaktov, ki vključujejo polimere, s poudarkom na vlogi kontaktne temperature pri določanju trenja in obrabe. V prvi fazi je bila izvedena obsežna eksperimentalna študija drsnih kontaktov polimer–jeklo v konfiguraciji modelnih triboloških testov tipa “pin-disk” pod zahtevnimi obratovalnimi pogoji, s posebnim poudarkom na vplivu debeline jeklenega diska – ki deluje kot toplotni ponor – na kontaktno temperaturo, trenje in obrabo. Rezultati so identificirali ključne parametre, ki vplivajo na kontaktno temperaturo, in pokazali njeno odločilno vlogo pri tribološki učinkovitosti teh sistemov, s čimer se poudarja pomen učinkovitega toplotnega upravljanja pri takšnih drsnih kontaktih. Na podlagi teh ugotovitev so bili razviti napovedni, uporabniku prijazni modeli za oceno največje kontaktne temperature v (1) polimer–jeklo in (2) polimer–polimer konfiguracijah “pin-disk”, ki pokrivajo širok spekter materialnih lastnosti, geometrij kontaktov in obremenitvenih pogojev. Razviti modeli predstavljajo pomemben napredek v razumevanju prispevka kontaktne temperature v eksperimentih tipa “pin-disk”, saj uporabljajo več novih modelnih pristopov. Zlasti modeli temeljijo na energijski bilanci celotnega tribološkega sistema teles v kontaktu ter upoštevajo disipacijo trenja zaradi različnih načinov odvajanja toplote: s konvekcijo, prevodom in sevanjem. Model za polimer–jeklo kontakte omogoča zelo natančne napovedi kontaktne temperature znotraj potrjenega eksperimentalnega območja, z negotovostjo približno 3?%. Podobno je tudi model za drsne kontakte polimer–polimer pokazal dobro ujemanje med napovedanimi in izmerjenimi vrednostmi pri specifičnih kontaktnih pogojih v tej študiji, z relativno negotovostjo približno 5?%. Ta raziskava ne le poglabljajo razumevanje toplotnih in triboloških interakcij v drsnih kontaktih na osnovi polimerov, temveč ponuja tudi praktična modelna orodja za načrtovanje, optimizacijo in toplotno upravljanje triboloških sistemov, ki vključujejo polimere.

• Keywords: kontaktna temperatura, mehanizmi obrabe, polimeri, trenje, metoda končnih elementov (MKE)