Static and Dynamic Analyses of a Rotor with Aerostatic Ceramic Porous Journal

Abstract

This work presents the numerical model of an experimental set-up where it was made an evaluation on the static characteristics of the shaft and the identification of the dynamic characteristics for an aerostatic radial porous bearing. The use of ceramic porous as journal for aerostatic bearings can improve its perform related to the wear, thermal stability, stiffness and load capacity allowing that spindles work with precision at speed above 20,000 rpm with small clearances (40 μ). In order to investigate these bearings were developed static analyses to obtain the deflection and stiffness of the support shaft, stiffness of the aerostatic porous bearing and dynamic identification for experimental set-up. The static analysis indicated stiffness of shaft and aerostatic porous bearing of 20.1 and 2.6 kN/mm, respectively. The dynamic analysis indicated that the first natural frequency of the rotor is close to 1365.9 Hz, which is much higher than the first natural frequency of the aerostatic ceramic porous bearing whose value is 775.0 Hz. One can concluded that geometrical configuration and support conditions choosen allow a robust condition to proceed the experimental tests in order to obtain dynamic characteristic of the aerostatic porous bearing.