Robust dynamic analysis of detuned-mistuned rotating bladed disks with geometric nonlinearities

Abstract

This work is devoted to the robust analysis of the effects of geometric nonlinearities on the nonlinear dynamic behavior of rotating detuned (intentionally mistuned) bladed disks in presence of unintentional mistuning (simply called mistuning). Mistuning induces uncertainties in the computational model, which are taken into account by a probabilistic approach. This paper presents a series of novel results of the dynamic behavior of such rotating bladed disks exhibiting nonlinear geometric effects. The structural responses in the time domain 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 and also allows physical insights to be given concerning the structural sensitivity. The bladed disk structure is made up of 24 blades for which several different detuned patterns are investigated with and without mistuning.

Nonlinear stochastic dynamics of detuned bladed-disks with uncertain mistuning and detuning optimization using a probabilistic machine learning tool

“…The amplitudes of these new resonances correspond to the indirect excitation of the first blade modes of the blisk and are of a lower order of magnitude in the present case, probably because the blades are not very slender. Note that this phenomenon has already been observed in previous analyses of nonlinear mistuned blisk for which the blades were slender structures, attached to the disk [36,47]. Moreover, the phenomenon for which the amplitude of the resonances located below the frequency band of excitation are dominant has been investigated in another context of sloshing in nonlinear fluid structure interaction [60].…”

“…With such a choice, the speed of convergence with respect to M of the projection remains fast enough for bladed-disks whose blades have a reasonable slenderness. When the gyroscopic coupling term is kept, an alternative method avoiding the calculation of complex modes can be used as proposed in [47]. It consists in using the proper orthogonal decomposition method (POD) applied to the nonlinear dynamical response of the rotating structure (including all the coupling terms) issued from a first nonlinear reduced-order model obtained with the linear elastic modes calculated without the gyroscopic coupling term.…”

“…This gives rise to the development and to the use of lighter materials, that have to be capable of high thermo-mechanical resistance and of long durability, so that it may be possible that the blade displacements respond in its nonlinear vibration range. In this context, a computational methodology and a robust analysis of the geometrical nonlinear effects on several detuned configurations of mistuned bladed-disk have been proposed in [47]. The results underline a complex nonlinear dynamical behavior and highlight a sensitivity of the nonlinear response to the detuning in presence of mistuning.…”

Detuning Optimization of Nonlinear Mistuned Bladed-Disks

“…This gives rise to the development and to the use of lighter materials, that have to be capable of high thermomechanical resistance and of long durability, so that it may be possible that the blade displacements respond in its nonlinear vibration range. In this context, a computational methodology and a robust analysis of the geometrical nonlinear effects on several detuned configurations of mistuned bladed disk have been proposed in [22]. The results underline a complex nonlinear dynamical behavior and highlight a sensitivity of the nonlinear response to the detuning in presence of mistuning.…”

Nonproportional Intentionally Mistuned Turbine Blisk Design with Improved Component Modal Synthesis

“…Intrinsically, the intentionally mistuned design is a robustness control and design, which got a rapid development since the 1990s. e robustness of blisks was analyzed [9,18,19]. e robustness of turbocharged components was investigated [20].…”