The dynamic characterisation of rolling-element bearings

Razpotnik, Matej (author), Boltežar, Miha (mentor)

The transmission of vibration through rolling-element bearings is a major topic of interest with respect to the modern rotating machinery. Due to the complex contact conditions the bearing modelling as part of a wider system primarily remains on the analytical level. This work discusses in the first part the adequacy of current analytical bearing models by comparing their load-displacement characteristics. Afterwards the bottom-up investigation of a system is presented. Based on precisely known dynamic properties of all integral parts but bearings we asses the dynamic bearing model. The next part of this work describes the numerical issues that appears when calculating the time response of a system containing rolling-element bearings. A derivation of smooth contact-state transition model is presented that ensures faster and stable integration procedure. In the last part the statically indeterminate system containing rolling-element bearings is investigated. More unknowns than available equations require a new numerical approach to calculate a resulting equilibrium of the system.

• Language: Slovenian
• Keywords: Rolling-element bearings, Dynamic bearing model, Stiffness matrixes, Smooth contact-state transition, Unbalanced rotors, Statically indeterminate systems
• Work type: Doctoral dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [M. Razpotnik]
• Year: 2019
• Number of pages: XXX, 136 str.
• PID: 20.500.12556/RUL-108481
• UDC: 621.822.6:531.395(043.3)
• COBISS.SI-ID: 16710427
• Publication date in RUL: 04.07.2019

Secondary language

• Language: English
• Title: Dinamska karakterizacija kotalnih ležajev

Abstract

Popis prenosa vibracij preko kotalnih ležajev predstavlja velik izziv pri načrtovanju sodobnih rotacijskih naprav. Zaradi kompleksnih kontaktnih pogojev ostaja modeliranje ležajev kot del širšega sistema pretežno na analitičnem nivoju. V prvem delu obravnavamo primernost obstoječih modelov ležaja s primerjavo karakteristik sila-pomik. Sledi numerična in eksperimentalna raziskava namensko zasnovanega sistema. Na podlagi natančno poznanih dinamskih lastnosti vseh ostalih sestavnih delov lahko ocenimo dinamski model ležaja. V nadaljevanju je predstavljena problematika numerične časovne integracije sistemov s kotalnimi ležaji. Z vpeljavo glajenja kontaktnih stanj je izpeljan dinamski model ležaja, ki omogoča hitrejši in stabilnejši integracijski postopek. V zadnjem delu obravnavamo statično nedoločen sistem, ki vsebuje kotalne ležaje. Več neznank kot poznanih enačb narekuje vpeljavo novega numeričnega postopka, ki omogoča izračun fizikalno smiselnega ravnovesja sistema.

• Keywords: Kotalni ležaji, Dinamski model ležaja, Togostne matrike, Glajenje kontaktnih stanj, Neuravnotežen rotorji, Statično nedoločeni sistemi