Theoretical modeling for a rotor-bearing-foundation system and its dynamic characteristics analysis

Abstract

Modeling for rotor-bearing-foundation systems is one of the key bases for efficient dynamic analysis in the field of turbomachinery. However it should be noted that the term foundation structure should be interpreted depending on the purpose of the rotating machine. Thus in heavy power machinery it is usually a massive fixed base structure made of steel frames and concrete e.g. for power generating turbine units, but in aerospace it is relatively light and flexible beam type wing for aircraft engines. Since rotating machinery such as modern aircraft engines usually designed, marketed and sold for the most part based on analytical and numerical predictions, methods to incorporate the foundation influence effect in rotordynamic calculations are very important. The aim of the current paper is to observe recent efficient approaches for foundation structure modeling and to point out contemporary methods used by engineers for foundation structure parameters identification. Further in the simulation section of the paper simplified models were created in modern FEM software packages in order to demonstrate foundation structure influence on the dynamics of rotor-bearing system and their interaction.