Author: Anthony Picou

Publisher:

Published: 2019

Total Pages: 0

ISBN-13:

The intentional mistuning, also called detuning has been identified as an efficient technological way for reducing the sensitivity of the forced response of bladed disks to unintentional mistuning (simply called mistuning), caused by the manufacturing tolerances and the small variations in the mechanical properties from blade to blade. The intentional mistuning consists in detuning the bladed disk structure by using partial or alternating patterns of different sector types. However, the recent technological improvements that include the use of more flexible and lighter blades can lead to large strains/displacements, which requires the use of nonlinear dynamic equations involving geometric nonlinearities. This work is devoted to the robust analysis of the effects of geometric nonlinearities on the nonlinear dynamic behavior of rotating detuned bladed disks in presence of mistuning. The detuning corresponds to uncertainties in the computational model, and are taken into account by a probabilistic approach. This thesis presents a series of novel results in dynamics of rotating bladed disks with mistuning and detuning in presence of nonlinear geometrical effects. The structural responses are computed in the time domain and are analyzed in the frequency domain. The frequency analysis exhibits responses outside the frequency band of excitation. The confidence region of the stochastic responses allows the robustness to be analyzed with respect to uncertainties, that is to say with respect to the level of mistuning. The bladed disk structure, which is used for the numerical simulations, is made up of 24 blades for which several different detuned patterns are investigated with and without mistuning.