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Rotor system of modern aero-engine together with the case mounted on the wing represents a uniform system that is supposed to be considered as a rotor-bearings-foundation structure. Nowadays rotating machinery such as modern aircraft engines usually designed, marketed and sold for the most part based on analytical and numerical predictions. In such a way methods to incorporate the foundation effect in rotordynamic calculations are very important. For investigation purposes a rotor-foundation test rig, which can simulate the aero-engine’s typical operating condition such as wing vibration and hard landing, was built to study the influence of foundation behavior on the dynamic characteristics of rotor system. To predict natural frequencies for the full system simplified models based on FEM approach were created. Moreover, simple numerical model was created to study influence of foundation kinematic excitation on behavior of rotor disk orbit. Furthermore simulation results were compared with experimental to understand influence of main parameters which define foundation vibration on rotor deviation from normal operation condition. Obtained numerical and experimental results can help to understand principles of rotating structure-foundation interaction when the later one subjected to excitation and could be further used for improving of more complicated models for design and enhancement of aircraft engines.

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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.

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