As one of the common faults that induce shafting vibration of large steam turbine units

crack fault seriously threatens the safety of power production. The enhanced aerodynamic effect of the seal on the rotor in high-parameter steam turbine can aggravate the vibration of the shaft system. In this paper

besides studying the vibration response of the cracked shafting

the dynamic response is analyzed based on the characteristic frequency of the frequency slice wavelet transform (FSWT) method in the refined response within the specified interval

considering the influence of steam excitation and other nonlinear factors on the shafting

. The results show that after the coupled steam flow excitation

the energy conversion and superposition between the frequency doublings in the time domain curve of the cracked shaft system are intensified. When the load of the unit increases

the system gradually changes from a "single-period" chaotic motion to a "two-period" chaotic motion. The span of the first frequency doubling is gradually reduced by 7.64%

11.66%

and 22.69%

and the fourth frequency doubling shows a small "wave-like" change.