Model Correlation of Dynamic Non-linear Bearing Behavior in a Generator
Efforts to correlate the dynamic response of a generator finite element model have revealed a "jump" phenomenon in the experimental vibration measurements of the generator system. The behavior is representative of a non-linear stiffening spring and is believed to be associated with the stiffness characteristics of the rotor shaft bearings. Current modeling techniques provide good correlation between analytical modal analysis results and frequency response functions made with an instrumented impact hammer. However, the resonant frequency of vibration predicted by the generator model does not correlate well with generator response data acquired on an electrodynamic shaker. This paper discusses the non-linear dynamic behavior of the generator response, as indicated by both physical and theoretical data.