Session: 27-06 Lateral-Torsional, Cracked, and Bent Rotordynamics

Paper Number: 100923

100923 - Coupled Lateral-Torsional Analysis With Structural Interaction on Geared Shaft 

In the theoretical framework of rotordynamic predictability, Baker Hughes has developed several validations of lateral torsional dynamic modeling. The train under study is a geared turbogenerator shaft line system that consists of a generator mounted on a baseplate and connected with a planetary reducer directly supported (overhung) on the generator frame. The gas turbine driver is not included in the modeling due to the use of a diaphragm flexible coupling connecting it with the reducer. The shaft line in object is then only composed by the planetary gear rigid connected with a generator solid poles rotor observed during mechanical running test (no load condition). The presence of the gearbox prevents lateral and torsional vibrations from being treated independently. Furthermore, the interaction of the rotordynamic system with its supports (machine frames, bearing housings and baseplate) is described using state space matrices approach. This modeling methodology is resulted very likelihood in predicting the dynamic system natural frequencies as well as peak level of reached vibration in all analyzed speed range. Operational modal analysis has been used to compare expected natural frequencies vs identified ones while the level of vibrations is induced by applying unbalance force in the proper location (i.e. shop test verification). 

Presenting Author: Mirko Libraschi Baker Hughes

Presenting Author Biography: I'm Mirko Libraschi and i work as mechanical vibration specialist for Baker Hughes Turbomachinery & Process Solutions since 2010. In 2018 i received my Six Sigma Black Belt certification. I directly followed Tilting Pad Journal Bearing test campaigns, identification methodology and analytical investigation. I'm specially involved on Root Causes Analysis and several research activities on rotodynamic with the main focusing on modeling predictability and uncertainty quantification of component/system level test activities.
I received my Mechanical Engineering degree in 2002 from the University of Pisa.

Authors:

Mirko Libraschi Baker Hughes
Francesco Capanni Baker Highes
Luca Innaco Baker hughes
Stefano Rossin Baker Hughes