Effect of shape errors on the stability of externally pressurized air journal bearings using semi-implicit scheme

Effects of shape errors on the dynamic behavior of externally pressurized air journal bearings are studied. A semi-implicit numerical scheme is used in order to reduce the computing time. A new algorithm is developed that can handle a non-tridiagonal matrix from the periodic boundary conditions of the journal bearing. Using this method, the half frequency whirl phenomena and instability threshold speeds can be effectively calculated for the bearings having shape errors on the surfaces of the shafts and bearings, respectively. It is shown that the effect of shape errors on the stability from the shaft and the bearing is different and the precision of the shaft is much more important than that of the bearing.