On the Critical Speeds of a Shaft due to the Deflections of Bearing Pedestals

Abstract

Usually, the uniformity of flexural rigidity of bearing pedestals in all directions may not be obtained. Owing to this non-uniformity of the rigidity, the critical speeds of synchronous backward procession can occur for the shaft with one disc. The results obtained may be summarized as follows : 1) There are two critical speeds, one is higher than the major critical speed, another is lower. 2) The amplitudes increase with the non-uniformity of the rigidity of pedestals. 3) Such critical speeds can occur for disc either loosely mounted or not. 4) The amplitudes vary as the location where a disc is attached to the shaft.