| A numerically efficient methodology is developed to compute the steady-state forced responses of a large multi-bearing system with short or finite length bearings, gyroscopic discs and hydrodynamic added mass/damping elements.; In this method, static equilibrium is calculated by reducing the number of nonlinear equations involving bearing forces and eccentricities to the number of bearing degrees of freedom and then solving the equations iteratively. Once the eccentricities are known at static equilibrium, linearized bearing coefficients are calculated at these positions. During these calculations, forces, moments and dynamic coefficients of a finite bearing at an arbitrary eccentricity are computed by a new finite element approach which requires only a slight modification of a general two dimensional finite element program.; With the linearized bearing coefficients, the forced responses are calculated by an impedance coupling method, which is extended to incorporate with finite length bearings, hydrodynamic added mass/damping elements and moment type excitations.; This methodology is applied to a ship vibration to determine the dynamic interaction between the propeller and the hull. Included are parametric studies on the damping coefficients, misalignments in the bearing vertical positions, bearing dimensions, and lubricant viscosity. |
