Gas turbine blade vibration

Blade vibration is one of the most significant causes of high cycle fatigue failure in gas turbine engines. A correctly conducted modal analysis can accurately predict the values of natural frequency. The most commonly used tool for such purpose is software based on Finite Element Method. Compared to experimental tests it is less costly, more time efficient and can incorporate phenomena which are not possible to include in experimental measurements. To perform such analysis correctly one must be aware of several significant parameters that should not be omitted in the model definition. This work focuses on main influencing factors such as working temperature, rotational speed, blade root stiffness and examines their effects. In addition it studies the importance of boundary conditions in the FEM model and verifies possible geometrical simplifications that could optimize the solution process. This analysis should be useful to engineers working on turbine blade vibration. The conclusions contained in the work can serve as guidelines for optimizing the process of turbine blade modal analysis and may help FE software users to obtain most accurate results in the least time.

Autorentext

MSc: Studied Mechanical Engineering and Applied Computer Science at the International Faculty of Engineering of the Technical University of Lodz. FEM Calculation Engineer at AMSC Windtec, Klagenfurt, Austria