Influence of the lubrication model on the dynamic response of mechanical systems

Abstract

The main objective of this work is to present a study on the use of different hydrodynamic force models on the dynamic response of mechanical systems with lubricated revolute joints. For this purpose, the fundamental issues related to the classical theory of lubrication for dynamically loaded journal-bearings are revised, which is used to evaluate the Reynolds’ equation for dynamic regime. The hydrodynamic forces that develop at the lubricated revolute joints are determined and included into the dynamic equations of motion. In this study, three different approaches are considered to evaluate the hydrodynamic forces, namely the Pinkus and Sternlicht approach for long journal-bearings and the Frêne et al. models for both long and short journal-bearings. Results for a mechanical system with a lubricated revolute joint are presented and used to discuss the main assumptions and procedures adopted in this work. From the computational simulations performed, it can be observed that the hydrodynamic force model play a crucial role in predicting the dynamic behavior of mechanical systems and originate some uncertainties in their dynamic responses.