Critical Speed Analysis of Rotor Shafts Using Campbell Diagrams

The main aim of this paper is to avoid the critical speed at low rotational velocities for three different cases, i.e. shaft without rotor, single rotor system and two rotor system. The critical speeds of these rotor systems are analyzed with two boundary conditions, viz. one end supported, both ends supported. Moreover, the rotors are mounted at two different positions: single rotor is placed at middle of the shaft and the same rotor is split into two halves and kept at equal distance from the either end of shaft. This critical speed analysis is carried out on both solid and hollow shafts. The
range of rotational speed for the analyses considered in between 0 to 5000 rpm. The critical speeds of various rotor systems are studied using Campbell diagram and it is observed that, the critical speeds are altered by changing the boundary conditions and replacing the solid shaft with hollow shaft of same torsional stiffness as well.