Combined Explicit Finite and Discrete Element Methods for Rotor Bearing Dynamic Modeling

TLDR: In this paper, the explicit finite element method (EFEM) and the discrete element method are coupled to investigate dynamics of flexible rotor systems supported by deep-groove ball bearings, where the flexible shaft is modeled with a full 3D elastic formulation using the EFEM rather than the reduced form.

Abstract: This article presents a new approach in which the explicit finite element method (EFEM) and the discrete element method (DEM) are coupled to investigate dynamics of flexible rotor systems supported by deep-groove ball bearings. In this investigation, DEM is used to develop the bearing (dynamic motion) model in which all of the components of the bearing (i.e., inner and outer race, balls, and cage) have 6 degrees of freedom. The flexible shaft is modeled with a full 3D elastic formulation using the EFEM rather than the reduced form, which implements component mode synthesis. The EFEM and DEM were combined to investigate the dynamics of flexible shaft rotor systems supported by ball bearings. Rotor and inner races of the bearings are fully coupled such that both translation and rotation of the flexible rotor are transmitted to the bearings. At each time step, the translational motion and rotation/tilt angle of the rotor cross section at the location of an inner race are applied to the inner race of the bear...