Date of Award


Degree Type



Mechanical Engineering

First Advisor

Rashidi, Majid

Subject Headings

Lagrangian functions, Vibration, Roller bearings, Lagrangian approach, phanikrishna, vibrations in a bearing


Vibratory behavior of a rolling element bearing on a horizontal rotor is studied in this work. This Thesis analyzes the dynamics of a typical roller bearing as a result of internal excitations. These internal excitations stem from the geometric deviations of the interacting surfaces from their ideal geometry. Such deviations in turn are the results of either manufacturing limitations or normal wear of the bearing surfaces. Lagrangian approach is implemented to derive the dynamic equations of motion. Matlab is used to solve the equation of motion of governing the vibrations of the system. Parametric studies are conducted to provide results for several excitation levels. The study shows, that for a surface waviness of 0.00001 (mm), the roller's radial displacement is about 1.5*10-6 (mm) under a linear analysis for a shaft speed of 2000rpm. Consideration of non-linear analysis predicted 2*10-15 (mm) for the roller radial displacement in response to the same surface condition. For shaft speeds of 2400 rpm, 3000 rpm, and 4000 rpm, the roller radial displacements for linear analysis are 8.5*10-7, 8*10-7, and 6*10-7 (mm) respectively. And for nonlinear analysis are 8*10-15, 2*10-16, 6*10-16 respectively