Abstract:For the reason that Reynolds equation is not suitable for reflecting hydrodynamic bearings with high speed rotation coupled by inertial effect of oil circumferential flow and dynamic squeeze effect of the journal,the calculating accuracy of dynamic stiffness coefficients can not satisfy optimal design of highprecision bearings.A new approach of calculating stiffness coefficients of journal bearings was developed.Transient oil film pressure distribution and transient oil film force were solved with ADINA firstly,and the orbits of shaft centerline was obtained.The dynamic stiffness of oil film was calculated with the difference calculation model.In the new approach,the fluid structure interaction and cavitation model are used,Arbitrary-Lagrangian-Eulerian(ALE)method is adopted to avoid the grid distortion of fluid domain in the fluidsolid coupling analysis between the oil and shaft.The dynamic balance process of the axis and the dynamic development process of the pressure distribution of the threedimensional flow field are well simulated by the new approach,and the dynamic oil film force and dynamic oil film stiffness in the transient process are obtained.The comparison between the experimental results and the calculation results based on fluid solid coupling and cavity model shows that the two are basically identical.It is shown that the numerical simulation method based on fluid solid coupling and cavity model is feasible and effective.