The nonlinear response of crack Jeffcott rotor in leveling and hovering state was studied

while a mathematical model of crack Jeffcott rotor in hovering state was set up

and the corresponding motion equation was derived.The results show that

there are three ways leading to chaos

which are quasi-periodic bifurcation

intermittence bifurcation and instability period-3 motion to chaos.Generally speaking

the hover can depress the nonlinear response of system

but increase considerably the amplitude of system response

thus creating a bigger possibility of axis crack and rotor collision.And

the hover will also lead to nonlinear response near the fraction frequency of swing critical speed.