Analysis of frequency and mode shape of rotating-flexible disk-drum coupled structure with non-continuous connections

This study focuses on the coupling vibration of a rotating-flexible disk-drum structure with a non-continuous connection, and investigates the frequencies and mode shapes of the coupled system. The Sanders' shell and the Kirchhoff plate theories were considered for the flexible drum and flexible disk, respectively. Artificial springs were utilized to represent the general boundary and non-continuous connection conditions. The rotating speed was also considered for the coupled structure to establish the dynamic equation. First, the proposed model was validated by comparing the results with those obtained from literature and using ANSYS. Next, numerical simulations were performed to determine the effect of the connection point number, rotating speed, connection stiffness, drum length, and disk thickness on the frequency and mode shape of the coupled structure in the static and rotating state. The results show that the frequency increases as the point number increases. When the point number is less than 16, the local deformation of the mode shape is obvious. The analysis of frequency curves, mode shapes, and MAC indicates that the essence of frequency veering, merging, and bifurcation is the vibration coupling and mode shape interaction between the coupling modes. The frequencies increase monotonically with the increased connection stiffness. The axial connection stiffness and disk thickness have a significant effect on the disk-dominant mode. The circumferential and radial connection stiffness and the drum length mainly affect the drum-dominant mode. Compared with other stiffnesses, the rotational connection stiffness has a smaller effect on the frequency of the coupled structure. In a rotating state, with a larger drum length or disk thickness, the frequency veering occurs at a lower rotating speed, while the frequency merging occurs at a higher rotating speed.

Automated summary

This study investigates the coupling vibration of a rotating-flexible disk-drum structure with a non-continuous connection, analyzing the frequencies and mode shapes of the coupled system. Results show that the frequency increases with the connection point number, with noticeable local deformation of the mode shape when the point number is less than 16. Analysis of frequency curves, mode shapes, and MAC indicates that frequency veering, merging, and bifurcation are primarily due to the vibration coupling and mode shape interaction between coupling modes.