Including foundation effects on the vibration behaviour of rotating machinery

Abstract Including foundation effects on rotating machinery vibrations is normally difficult and very approximate owing to the complicated foundation configuration and its interaction with the surrounding environment, necessitating experimental identification of the foundation parameters. This paper presents and evaluates numerically a promising technique for identifying mass, damping and stiffness parameters of a field foundation supporting unbalanced rotating machinery. All necessary measurements can be taken during a single run-down. Moreover, only a knowledge of the bearing characteristics and measurements of rotor and foundation motions at selected co-ordinates (including the connections) and at selected speeds are needed. In particular, the method does not require an accurate rotor model, nor a knowledge of the actual unbalance distribution.