THE PHENOMENON OF LOCALIZATION OF VIBRATION MODES IN AIRCRAFT TURBINE BLADES
The present work refers to the identification and analysis of structural issues in aeronautical engine blades referring to the possible occurrence of the Phenomenon of Vibration Modes in Aeronautical Turbines. This involves the distribution of vibrational energy in turbine models in which a large number of nominally identical subsystems (the blades) are coupled by the rotor to which they are attached. Thus, an analysis was adopted considering, first, an ideal model, where we have characteristics, such as length, stiffness, angle of the blades, etc., given as identical for all subsystems. In this case, the vibration modes extend to the entire set of blades. Next, the model is considered for a more real consideration, varying certain structural characteristics of the blades (in this work, the focus was on varying, in the first analysis, the length of the blades, in the second analysis, their stiffnesses and, finally, their angulation). It is shown that, in this type of more real model, the Phenomenon of Paddle Vibration Modes in Aeronautical Turbines appears and must be considered, disregarded that it was in the ideal model. In this phenomenon, the vibration energy ends up being located in only part of the system, sometimes in a single blade. For these analyzes, the Matlab language was used in a program based on the Finite Elements Method to identify the vibration modes of a cyclic system such as turbine, generating graphs to allow a better visualization of the presence of this phenomenon and the comparison between the models, real and ideal.