A kind of modified Jeffcott rotor/stator system was studied

both stability characteristic and reliability characteristic were analyzed while considering the influence of parameter's random distribution. A reliability formula was deduced as well as the reliability index of 0.95 is calculated by using the FORM (first order reliability method) and CMC (Crude-Monte-Carlo) method respectively. In addition

the boundary of rubbing problem is determined due to the reliability requirement. Furthermore

the effects of various parameters on the rotor steady-state response and security domain were discussed as well as the sensitivity of parameters also been considered. Finally

the solution of general rotor/stator rubbing problem is derived in the space of three parameters(coefficient of friction

speed and clearance) corresponding to the specific requirement in practice.