Numerical Investigation of a Mistuned Academic Bladed Disk Dynamics With Blade/Casing Contact

Abstract

<jats:title>Abstract</jats:title> <jats:p>This contribution focuses on the combined analysis of mistuning and unilateral blade-tip/casing contacts. A 2D phenomenological finite element model of an aircraft engine fan stage is considered. It is reduced by means of the Craig-Bampton component mode synthesis method and contact treatment relies on a Lagrange multiplier algorithm within an explicit time-integration scheme. Blade-tip/casing contacts are initiated through the deformed shape of a perfectly rigid casing. Mistuning is accounted for on the blades only. Monte Carlo simulations are carried out in both linear and nonlinear configurations, which allows to compare amplifications predicted in both context due to mistuning. Following a thorough convergence analysis of the proposed numerical strategy, the influence of mistuning level as well as the configuration of the external forcing are investigated. Presented results underline the detrimental consequences of mistuning in a nonlinear structural context, yielding even higher vibration amplifications than in a linear context. A cross-analysis between linear and nonlinear computations reveals that no correlation is found between linear and nonlinear amplifications which suggests that the effect of existing strategies to mitigate vibration amplifications within a linear context may not be suitable within a nonlinear context.</jats:p>

Investigation on the Robustness of Rotor/Stator Contact Interactions With Respect to Small Mistuning

“…Samples are therefore approximately equally spread on both sides of the diagonal line. This observation differs from the conclusions derived from the phenomenological model in [16], for which the amplification factors were increased when considering contact nonlinearities. However, the contact stiffening was higher in the case of the phenomenological model (no abradable layer was modeled that soften the blades/casing contacts), which can explain this difference in the behavior.…”

“…The vast majority of studies on rotor/stator interactions have been conducted considering a single blade [15]. First investigations on full bladed disk dynamics have been carried out using a two-dimensional phenomenological model in both tuned and mistuned configurations [16]. On this academic model, a higher amplification of the vibration amplitudes has been evidenced in a nonlinear context compared to linear forced responses.…”

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

“…[12,13,14,15,16,17,18]). A research effort has also been made for the construction of nonlinear reduced-order models allowing for the mistuning analysis of bladed-disk in presence of contact nonlinearities [19,20,21,22,23,24,25]. Moreover, due to technological evolutions that involve lighter materials and thinner blades, the nonlinear geometrical effects induced by finite displacements cannot longer be neglected.…”

A novel mathematical model for the design of the resonance mechanism of an intentional mistuning bladed disk system

“…The results show that intentional mistuning has a great effect on the vibration localization. Intentional mistuning of the bladed disk is used to reduce the larger forced response (Corral et al, 2018;Martel and Sanchez-Alvarez, 2018;Gao et al, 2020;Joachim et al, 2021;Repetckii, 2020). An intentional mistuning bladed disk changes the vibration localization by designing the structure parameter (Nakos et al, 2021;Picou et al, 2018;Beirow et al, 2021;Biagiotti et al, 2018;Schlesier et al, 2018).…”