Nonlinear dynamic characteristics of ceramic motorized spindle considering unbalanced magnetic pull and contact force effects

The ceramic motorized spindle is widely used in precision machining due to the properties of the ceramic material such as inverse magnetism and small deformation. There are complex magnetic-thermal physical fields in the motorized spindle. This can lead to its internal parts stress complex. In order to study the nonlinear dynamic behavior of ceramic motorized spindle, the unbalanced magnetic pull is calculated through Maxwell considering inverse magnetic. Meanwhile, the radial displacement is analyzed and the contact force is solved. Then, the centralized mass approach is employed to simplify the construction of the spindle, and a mathematical model with 10-DOFs is constructed. In this study, the nonlinear vibrational characteristics of ceramic motorized spindles are thoroughly analyzed using bifurcation and Poincare section diagrams. The investigation reveals that as the rotational speed increases, the system transitions through various bifurcation states, including periodic, inverted, and chaotic. The impact of the nonlinear contact force is found to be significant on the rotational frequency, while the unbalanced magnetic pull predominantly influences the 2 subharmonic frequency. Enhancing the preload has been observed to augment system stability effectively. A comparison between experimental data and simulation models indicates a high degree of congruence, with the maximum frequency domain error being capped at 3.05%. These insights provide a robust theoretical base for advancing research and development in the field of ceramic motorized spindles.