A new elastohydrodynamic model for lubricated cylindrical joints in flexible multibody system

摘要

The Absolute-Coordinate-Based (ACB) method that combines the Natural Coordinate Formulation (NCF) describing rigid rotating journal and the Absolute Nodal Coordinate Formulation (ANCF) describing flexible bearing is used to study elastohydrodynamic behaviors of the lubricated cylindrical joints in flexible multibody system.A new elastohydrodynamic (EHD) model of lubricated cylindrical joint is proposed in which the flexible bearing is modeled by the twenty-node hexagonal element of ANCF and the lubricant pressure is obtained through solving the Reynolds’ equation using the finite-difference method. To enhance the computation efficiency, the elastic forces and their Jacobian of the ANCF finite element are derived from the definition of the Piola-Kirchhoff stress tensor of the first kind in the continuum mechanics. The assembled huge set of equations of motion for the constrained flexible multibody system with lubricated cylindrical joint is efficiently solved by using OPenMP based parallel algorithm.Finally, two numerical examples are studied to validate the ACB method and the proposed EHD model.Some numerical results are also verified by using the commercial software ADINA.