Taking the three-span rotor shaft system as the research object

the orthogonal test method with interaction was used to analyze the influence of bearing position on the vibration characteristics of the rotor shaft system

and find out the optimal combination of bearing position and the primary and secondary orders of the influence on vibration. The simplified rotor shaft system model was introduced into ANSYS Workbench to simulate the vibration near the critical speed of the system at different bearing positions. The minimum vibration deformation in the first three order vortex states was the target parameter

and the relationship between the bearing position change and the target parameters was obtained. The results show that the interaction of bearing Ⅰ×Ⅱ has a great influence on the vibration characteristics of the shaft system

the position of the bearing Ⅰ has the greatest influence on the vibration characteristics of the shaft system

and the position of bearing Ⅲ has a relatively small influence.