Probabilistic Response of a Bladed Disk With Uncertain Geometry

Abstract

Geometric uncertainties in the blade manufacturing process have important consequences in terms of dynamical properties of bladed disks. In this paper, we address the problem of modeling a full bladed disk composed by blades having uncertain geometry. The geometric imperfection of the blades is represented and analyzed according to a procedure previously presented by the authors, based on the principal component analysis (PCA) and the mesh morphing. The dynamical model of the full disk is constructed following the component mode synthesis (CMS) approach. The blade geometry is represented using a probabilistic model constructed from an experimental dataset. The effect of the geometric uncertainties is assessed using a linear uncertainty propagation approach, leading to a procedure that is fast enough to be embedded into a Monte Carlo simulation (MCS) loop.

Sector Mode Assembling Reduction Technique for High-Fidelity Blisk Models with Geometry Mistuning

“…By comparison, the system-mode-based reduction methods in literature employ an expanded projection basis by incorporating more sets of cyclic modes for different geometrically mistuned sector types. Accordingly, the projection basis size in the column dimension becomes n m × n s , provided that the total number of different geometrically mistuned sector types is n s and n m cyclic modes are retained for each sector type, respectively [30], while the ROMs derived by the componentmode-based reduction methods in literature are generally of even larger size because the interface DOFs of each sector are partly preserved [27,28].…”

“…Although the interface DOFs can be reduced through a posteriori secondary modal analysis [27], it still requires high computational cost that scales heavily with the number of the constraint modes. An appealing improvement, referred to as the orthogonal polynomial series method, was recently proposed to efficiently calculate the constraint mode matrix in a reduced form, meanwhile significantly eliminating the interface DOFs in the final ROM [28].…”

A novel model reduction approach for blisks with blend repairs and small mistuning

“…The general substructuring step allows a straightforward integration of both small blade geometric mistuning and large blend repairs. In particular, a reduced set of principal components can be used to represent the small blade geometric variances [15,16]. The Mode-Accelerated XXr method proposes to incorporate blend acceleration modes for bladed disks with large blends so that the size of the ROM can be lowered down [17,18].…”

Experimental Investigation on a Bladed Disk with Traveling Wave Excitation

“…Similar to the mode shapes, each travelingwave force component is characterized by its HI, which is referred to as engine order (EO). The prediction of mistuning at design or construction stage is complicated due to its intrinsic randomness [6][7][8][9][10]. Mistuning can be identified experimentally by observing its effects on the dynamic response of the disk [11][12][13][14][15].…”