Nonlinear Pad Functions for Static Analysis of Tilting Pad Bearings

An experimental procedure was developed for the determination of pad bearing performance by means of nonlinear stiffness pad functions. These functions describe the pad reaction for each location of the journal. The performance of the complete bearing is then computed from the assembly of the individual pad functions. This yields a complete static nonlinear description of the bearing forces. The same method, that is by using nonlinear damping pad functions, can as well be used for investigating the dynamic behavior of tilting pad bearings. This procedure can be used in two ways: (a) To tabulate the functions for an adequate constellation of the design parameters of the pads and from them compute the performance parameters of the bearing such as load carrying capacity and linear coefficients, (b) To incorporate these functions into a nonlinear numerical analysis of the dynamic response of the rotor-bearing system. Comparison of the static state results with previous investigations on complete bearings shows a good agreement while existing numerical solutions give unacceptable results for wide areas of bearings operation.