Predicting Blade Stress Levels Directly From Reduced-Order Vibration Models of Mistuned Bladed Disks

Abstract

The forced vibration response of bladed disks can increase dramatically due to blade mistuning, which can cause major durability and reliability problems in turbine engines. To predict the mistuned forced response efficiently, several reduced-order modeling techniques have been developed. However, for mistuned bladed disks, increases in blade amplitude levels do not always correlate well with increases in blade stress levels. The stress levels may be computed by postprocessing the reduced-order model results with finite element analysis, but this is cumbersome and expensive. In this work, three indicators that can be calculated directly from reduced-order models are proposed as a way to estimate blade stress levels in a straightforward, systematic, and inexpensive manner. It is shown that these indicators can be used to predict stress values with good accuracy relative to finite element results, even for a case in which the displacement and stress levels show different frequency response trends.

Circulant Matrices and Their Application to Vibration Analysis

“…However, if the coupling is weak, so that the system frequencies are clustered near those of the isolated sector model, the possibility of localization is significantly increased. This topic has been investigated quite thoroughly, primarily in the context of the vibration of bladed disk assemblies with small blade mistuning; see, for example, [72][73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88]. Also, nonlinear effects can couple linear modes under certain resonance conditions, even at small amplitudes [118].…”

“…This behavior, which stems from the seminal work of Anderson on lattices [71], was originally recognized to be relevant to structural vibrations by Hodges and Woodhouse [72,73] and Pierre and Dowell [74], and has been extensively studied from both fundamental [75] and applied [76][77][78] points of view. The phenomenon of mode localization is also observed in the forced response and has practical implications for the fatigue life of bladed disks in turbomachinery [79,80]. It is interesting to note that localization also arises in nonlinear systems with perfect symmetry, where the dependence of the system natural frequencies on the amplitudes of vibration naturally leads to the possibility of mistuning of frequencies between sectors if their amplitudes are different [81][82][83][84][85][86][87][88].…”

Numerical investigation dynamics and durability of bladed disk of turbomachinery with mistuning parameters

“…В качестве переменной нагрузки рассматривалась сила, определяемая с помощью ряда Фурье [7,[15][16][17]:…”

Vibratory characteristic analysis of integral mistuned bladed disk assemblies for aeroengine

“…Based on the CMS, Bladh et al 9,20 used the ROM to analyze the probability of forced response, then a secondary modal analysis reduction technique was proposed and the computational efficiency was further improved, but computational accuracy was seriously declined. Lim et al 21 predicted the blade stress level from reduced-order vibration model of mistuned bladed disk assemblies (BDA). In his work, three indicators which were calculated directly from ROM were proposed as a way to estimate blade stress level in a straightforward, systematic, and inexpensive manner.…”

“…Lim et al. 21 predicted the blade stress level from reduced-order vibration model of mistuned bladed disk assemblies (BDA). In his work, three indicators which were calculated directly from ROM were proposed as a way to estimate blade stress level in a straightforward, systematic, and inexpensive manner.…”