Based on the work of Chu and Pilkey

a new direct integration method for the transient analysis of nonlinear rotor-bearing systems is proposed

called Continuous-Space Discrete-Time(CSDT)-Riccati transfer matrix integration method. In this method

the transfer vector ｛f…｝ Trather than the previous ｛f…e｝ T is used with the aid of the Newmark generalized acceleration formulation;the accelerations of all stations

not the deflections

are computed by the Riccati transfer matrix method

in result the method's numerical instabilities are improved.The method sustains the advantages of the Riccati transfer matrix method

i.e.

it is staightforward

easy to be understood

very convenient to use

quite stable

and capable to reduce the computation time and memory space significantly.So

it is especially fit to calculate the transient response of large complex rotor-bearing systems containing nonlinear elements.The method is illustrated and tested for the transient response of an unbalanced flexible rotor incorporating squeeze-film damper without centralizing spring.The obtained results agree well with those of the lumped mass method.For comparison an numerical example of the transient response of the above system has been also computed

using the transfer vector｛f…e｝ T.The obtained results show that such an integration is unstable.The reason of the unstability is also analyzed in this paper.