High-Fidelity Sensitivity Analysis of Modal Properties of Mistuned Bladed Disks Regarding Material Anisotropy

2019

Engineering Reports

Monocrystalline blades used in gas turbines exhibit material anisotropy, and the orientation of the anisotropy axis affects the deformation of the bladed disk. Considering the orientation of the anisotropy axis as a random design parameter, the uncertainty and sensitivity analysis for static blade deformations are presented for the first time. The following two cases are analyzed using a realistic bladed disk model with friction contacts: (i) deformation of the tuned bladed disks considering the uncertainty in anisotropy orientation and variations in fir tree root geometry and (ii) deformation of mistuned bladed disks with uncertain blade crystal orientations. For efficient uncertainty and sensitivity analysis, the applicability of the following surrogate models are explored: (i) an ensemble of regression trees (random forest) and (ii) gradient‐based polynomial chaos expansion. Faster convergence in statistical characteristics has been obtained using a surrogate model compared to that obtained from finite element model based Monte Carlo simulation. From sensitivity analysis, it has been inferred that the uncertainty in static displacements of a blade in a bladed disk is primarily due to the uncertainty in anisotropy angles of that blade itself and secondarily due to the interaction of different blade anisotropy angles.

“…The capability for sensitivity analysis with respect to material anisotropy orientation was introduced in CalculiX as part of the current project. 54…”

Section: Bladed Disk Modelsmentioning

confidence: 99%

“…The FE analysis is performed using CalculiX , which is an open source FE analysis package. The capability for sensitivity analysis with respect to material anisotropy orientation was introduced in CalculiX as part of the current project …”

Section: Numerical Studies Of Bladed Disk Modelsmentioning

confidence: 99%

Uncertainty and global sensitivity analysis of bladed disk statics with material anisotropy and root geometry variations

Rajasekharan

2019

Engineering Reports

“…where, the c jk and s j are the coefficients of the series expansion and the residual term accounting for the mode shapes not included in the summand respectively. For the detailed description of the calculation of the sensitivity of mode shapes the reader is referred to the earlier work of the authors [10].…”

Section: Sensitivity Calculation Of Modal Propertiesmentioning

confidence: 99%

“…in [8] for turbine buckets using computational and experimental means and in [9] for simple beam models. The study of the sensitivity of the natural frequencies and mode shapes with respect to the crystal orientation parameters of bladed disks has been presented in [10], which shows significant sensitivities for the blade dominated and localized mode shapes.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity and Forced Response Analysis of Anisotropy-Mistuned Bladed Disks With Nonlinear Contact Interfaces

Koscso

Journal of Engineering for Gas Turbines and Power

2019

Self Cite

A new method has been developed for the analysis of nonlinear forced response of bladed disks mistuned by blade anisotropy scatter and for the forced response sensitivity to blade material anisotropy orientations. The approach allows for the calculation of bladed disks with nonlinear friction contact interfaces using the multiharmonic balance method. The method uses efficient high-accuracy model reduction method for the minimization of the computational effort while providing required accuracy. The capabilities of the developed methods are validated and demonstrated using a two-blade model. A thorough study of the influence of the material anisotropy mistuning and its sensitivity on the characteristics of the forced response is carried out using finite element (FE) modes of anisotropy mistuned realistic bladed disk with nonlinear friction joints of blade roots and shroud contacts. The dependency of the nonlinear forced response on excitation level and contact pressure values has been carried out for anisotropy mistuned bladed disks.

Section: Introductionmentioning

confidence: 99%

Sensitivity and Forced Response Analysis of Anisotropy-Mistuned Bladed Disks With Nonlinear Contact Interfaces

Koscso

Volume 7B: Structures and Dynamics

2019

Self Cite

A new method has been developed for the analysis of nonlinear forced response of bladed disks mistuned by blade anisotropy scatter and for the forced response sensitivity to blade material anisotropy orientations. The approach allows for the calculation of bladed disks with nonlinear friction contact interfaces using the multi-harmonic balance method. The method uses efficient high-accuracy model reduction method for the minimization of the computational effort while providing required accuracy. The capabilities of the developed methods are validated and demonstrated using a two-blade model. A thorough study of the influence of the material anisotropy mistuning and its sensitivity on the characteristics of the forced response is carried out using finite element modes of anisotropy mistuned realistic bladed disk with nonlinear friction joints of blade roots and shroud contacts. The dependency of the nonlinear forced response on excitation level and contact pressure values has been carried out for anisotropy mistuned bladed disks.