Bearing Wear and Its Effect on Shaft Alignment

Abstract

The combined wear of water-lubricated bearings supporting a flexible shaft has a modal characteristic, that is, the cumulative wear can be represented by distinct patterns (modes) that increase geometrically at unique rates. The instantaneous wear rates decrease exponentially with time and approach zero asymptotically. The total load on the outboard bearings decreases and the total load on the inboard bearings increases: the redistribution of outboard and inboard loads is controlled by the shaft stiffness matrix (the reaction influence numbers). The characteristics of modal wear are examined and the changes in alignment loads are calculated, particular attention being paid to reduction-gear loads. Numerical results are displayed.