Accurate identification of the frequency response functions for the rotor–bearing–foundation system using the modified pseudo mode shape method

Theoretical Modeling for a Rotor-Bearing-Foundation System and Its Dynamic Characteristics Analysis

“…Bonello and Brenn showed in [15] a mechanical impedance technique for modeling of the dynamic behavior of a rotor on flexible foundations, concluding that sometimes it's cheaper and easier to measure dynamics of the foundations rather than to model them, since further they could be combined with theoretical model in so-called hybrid model. Chen et al [16] described a pseudo mode shape method based on use of frequency response function for establishing equivalent mass, damping and stiffness matrices of the foundation without having to build the physical model. A combination of finite elements and transfer matrix approach to add foundation effect in rotordynamic calculations was proposed in [17,18] by Feng et al with further experimental validation [19].…”

Experimental evaluation of a modal parameter based system identification procedure

“…After all, we are seeking for a general procedure to identify the equivalent system, which predicts the frequency response over the frequency range of interest correctly. Thereby, proportional damping model, which could be presented by diagonalisable damping matrix, was adopted, since it is a commonly used damping model in modal approach [2,6,[8][9]. The extension to a more accurate assumption of asymmetric though not necessarily diagonalisable damping matrix is left for future work.…”

“…Traditional modal approach usually solves the non-linear modal analysis equation for the modal parameters of all vibration modes simultaneously [6][7][8][9]. In our earlier work, we developed an approach to decouple the modal analysis equation so that each vibration mode could be solved independently; thereby, the number of unknowns in each individual identification equation was significantly reduced and the solving procedure was simplified [10].…”

Analysis on Coupling Faults Induced Vibration of Hydropower Unit

“…Among the various vibration causes, 70% was found to relate to the shaft system faults, such as unbalance and misalignment. Therefore, the dynamic feature of hydropower unit rotor has been researched as a popular topic, and achieved some process [3][4][5][6]. For example, Ref [3]employed the time-spectrum analysis on impact signal and displacement signal to characterize the dynamic rotor motion; Ref [4]combined the simulation with the experiment, and explored the relationship among peak-to-peak value of vibration, rotating rate and crack depth.…”