Dynamic Coefficients Identification of Water-Lubricated Hybrid Bearings Used in High-Speed Spindles with Different Excitation Methods

Figure 5

Comparative results of the damping coefficients by noncontact harmonic excitation: two rotating speeds (6,000 r/min and 9,000 r/min), three supply pressures (1.2 MPa, 1.5 MPa, and 1.8 MPa), and two exciting frequencies (4 Hz and 60 Hz).

(a) Direct damping,

(b) Cross damping,

(c) Cross damping,

(d) Direct damping,