Automatic Generation of Radial Ball Bearing FE-Models

Abstract

In Finite Element (FE) analyses of transmission components such as gearboxes or di erentials, there is a need for accurate bearing models to predict the behavior and properties of the system. The models also needs to be easy to implement and generate, and relatively simple to be fast and stable. This thesis deals with the radial ball bearings speci cally. Initial literature studies found it suitable to model the outer ring with solid elements and the inner ring with either solid elements or a rigid body from the rolling elements to the load center. The rolling element were replaced with nonlinear elastic springs with sti ness calculated based on Hertz contact theory to capture the contact zones deformation which is the most signi cant factor to the overall bearing sti ness. For the model to be easy to create, a script was written in Python to generate an ABAQUS input le from bearing properties speci ed in a text le for radial ball bearings. The input le for the bearing can then be loaded and implemented into a larger FE-model. Main focus of the thesis was to create a functional script that would generate a stable and reliable radial ball bearing model that could be used and relatively easy be modi ed for future needs. The model performs well with respect to convergency and low calculation times. Unfortunately the sti ness is much lower than measured results from real bearings. A close look at the deformation of the ring raceways gives us a reason to believe that this is because our springs are attached in a single node to the raceway and thus giving us a contact point to where all the transfered load between the rings is concentrated in, instead of a contact area as in a real bearing. Keywords: radial ball bearing, ABAQUS, python script, automatic FE-model generation, Hertz contact theory