Development of a Roller Bearing Model for Multibody Simulations: Bearing Vibration Transfer Path Analysis

Abstract

Mechanical systems are major sources of sound radiations and vibrations, even in their good operating conditions. The vibro-acoustic transfer functions of mechanical systems are crucial in Noise Vibration Harshness (NVH) analysis. Rotating machines are among common applications in mechanical engineering. Every mechanical component in rotating machines affect the total vibration transfer path. For this reason, for an accurate NVH modelling of the system, the detailed modelling of each component is required. With the advancements in commercial multibody simulation software and computational capacity of the modern computers, it is possible to model and simulate complex multibody systems. Rolling bearings are considered as the key elements in motion and vibration transmission. They are utilized to carry shaft and transmit the motion. Therefore, rolling bearings need to be modelled accurately by considering their varying dynamic characteristics. A number of studies have proposed and investigated various bearing dynamic models to estimate their dynamical behavior. Although available models have widely being used in industry and academia, their accuracy in estimation of bearing vibrations and vibration transfer path is still doubtful. In this regard, modelling and implementation of the rolling bearing contact mechanism plays major role in bearing vibration transfer path function. Rolling bearing contacts are usually considered as Hertz contact in the literature. In contrast, the recent investigations show the importance of the Elastohydrodynamic (EHD) contacts in dynamic modelling of mechanical parts. The EHD contacts can be simulated and analyzed using Reynolds and Computational Fluid Dynamics (CFD). Within the objectives of the current study, three rolling bearing dynamic models based on three various contact models using, Hertz, Reynolds, and CFD are developed. For this purpose, bearing contacts are considered as Kelvin-Voigt spring-dampers, and extended to a total rolling bearing model in a Multibody Simulation (MBS) environment. Then, their dynamic properties and transfer paths are investigated and compared numerically in the time and frequency domain. The numerical results illustrate and highlight the differences and limitations of the above mentioned bearing contact modelling methods in the context of the total bearing model.