Stability analyses of a cracked shaft subjected to the end load

Abstract The stability of a rotating cracked shaft subjected to the end load, an axial compressive force, is studied and the influences of the existing open crack on the natural whirling speeds of the shaft are discussed. A finite element model of Timoshenko beam is adopted to approximate the continuous shaft part, and the effects of the rotary inertia, shear deformations and gyroscopic moments are taken into account. The results show that two principal instability regions of different types (one of the types is divergence and the other is flutter) occur when the cracked shaft is subjected to an increasing end load. The influences of the crack are significant for the dynamic behaviour of the system as the depth of the crack reaches certain values, and would make the shaft's forward whirling frequencies less than backward ones.