Figs.10.4 (a),and (b) show Campbell diagrams for the present problem with 1 and 20 elements, respectively. Table 10.3 lists the critical speeds up to the third mode with and without gyroscopic couple. It should be noted that the critical speed without gyroscopic couple is always in between the corresponding mode forward and backward whirl critical speeds, which indicate the splitting of natural frequency in the case of gyroscopic effect. It can be observed that the split in the whirl natural frequency is distinct at higher speeds and at higher mode numbers. Fig 10.5(a) and (b) show mode shapes for translational and rotational displacements, respectively.