BENALI, A. BONIFACIE and D. NICOLAS

Pivoted-pads thrust bearing are commonly used to support axial load in rotating machinery. Analysis of such bearing is complicated by the ability of each pad to pivot, as the rotor is displaced and to translate axially due to the flexibility of the pad support. This leads to dependance of linearized stiffness and damping coefficients on rotor vibrational frequency, pad inertia and support dynamic characteristics. 

This paper describes an approach based on the pad assembly technique often used to develop pad journal bearings. A reduced matrix (3,3) can be developped once a vibrational frequency is assumed. Conclusions on the role of pivot support and mass pad are derived. 

This paper presents a linear dynamic analysis of tilting pad thrust bearing with damped flexible supports. The dynamic behavior is characterized by a set of reduced dynamic coefficients which depend on pad mass, stiffness and damping support and frequency of vibration. 

Fig 1 shows a schematic representation of the thrust consists of a runner which rotates at a constant angular speed m and tilting pads (k) with pivots (0. ) which are mounted on a plane througth a compliant support (k, c ). It is assumed that the pads and the runner are rigid and plane. 

The reference frame (X, Y, Z) has its origin located in the center 0 of the pad carrier ring with the Z axis normal to ring face. The local pad coordinate systems (xj, y, with X axis colinear to 00, is also fixed. The circumferential coordinateP is taken counterclockwise from the axis x  

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