An Investigation of Finite Element Models of Roller Bearings
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Typ
Examensarbete för masterexamen
Program
Applied mechanics (MPAME), MSc
Publicerad
2021
Författare
Rahani, Ramin
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Increasing demands on the design of transmissions for heavy trucks include higher
loads, longer lifetime and reduction of noise. To design gearboxes with aid of the finite
element method it is important to obtain precise force transfer and thus accurate
stress distribution close to a roller bearing seat. Therefore, stable and numerically
accurate bearing models are necessary. The purpose of the thesis is to accurately
describe the local or average behavior of roller bearings and to present finite element
results of the required detail level close to the bearings. It entails calibration of
bearing models with results from commercial bearing analysis tools. The objectives
are to find improved ways to model the change from contact to play between the
rollers and the rings, study stiffness of different bearing distribution models, investigate
mesh-sensitivity and implement axial stiffness in the bearing models. The
Abaqus finite element software is used to predict the behavior of roller bearings.
The analysis includes modelling of bearings and execution of load steps. Matlab
scripts are used to post-process the bearing models and evaluate them with bearing
analysis tools. The commercial software Shaft and Bearing Analysis (SABR) is used
to create bearing reference models. An optimization process is implemented with
Matlab to automate the convergence process of SABR. The developed model with
GAP-elements agrees with the reference model in the same way as the model using
nonlinear springs. Bearing models with different distribution loads show increasing
deformation as the ring thickness increases. For bearings of extreme sizes, it is
found that small rollers are slightly more flexible and large rollers a bit stiffer. The
mesh study demonstrates that the relative size difference between adjacent elements
does not affect the stiffness. When the spring spacing is equal to or smaller than
the element size, the bearing stiffness is not affected by the spring spacing or the
element size. The deflection of the bearings is influenced by the axial play. Axial
stiffness should be high and does not give a large contribution to the total deflection.
The results from the Abaqus bearing models provide good accuracy to model pure
radial, pure axial and a combination of radial and axial loads along with bearing
misalignments.
Beskrivning
Ämne/nyckelord
Axial , Radial , Rings , Roller bearing , Springs , Stiffness