Abstract
This paper proposes an analysis model of oil damper under extremely small excitation that is modeled based on its mechanism and shows its availability for applying to time history analysis. Under small excitation, with damper stroke as below about 0.5 mm, the damper force becomes linear to the second power of input velocity and the stiffness of oil descends with air bubble in it. Furthermore, friction resistance of packing seal becomes apparent and it depends on its pressure. Considering those characteristics properly, the results of time history analysis with the model follows ones of the experiment.
