Foundation modelling and implementing its dynamic behavior into a rotor system by using frequency response functions

Abstract

The purpose of this research work to implement the dynamic behavior of a foundation structure into a rotor-bearing system by using equivalent matrices. Thus, a foundation structure was modelled using a computationally aided design program. Then, modelled structure was analyzed by using finite element methods to obtain the frequency response functions of the structure. Afterwards, by using modal analyses and single-degree-of-freedom curve-fitting method, equivalent matrices of foundation structure were calculated. For equivalent matrices, maximum amplitude frequencies were chosen from frequency response functions. Furthermore, calculated matrices were implemented into a rotor-bearing system by using built-in finite element code. Then, rotor-bearing-foundation system and rotor-bearing system with implemented equivalent matrices were compared in terms of natural frequencies at zero rotation speeds. Finally, it was seen that, calculated equivalent matrices are capable of implementing the chosen frequencies.