TITLE

Rotor-pala sistemlerinde mil burulma-pala eğilme bağlaşık titreşimleri

AUTHOR(S)
Bulut, Gökhan; Turhan, ÖZgür
PUB. DATE
April 2010
SOURCE
ITU Journal Series D: Engineering;Apr2010, Vol. 9 Issue 2, p40
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Vibrations of rotor-blade systems is an important research topic due to very important applications such as aeroplane and helicopter propellers, compressors, fans, turbo-machines, etc. In those application areas, accurate prediction of vibration characteristics is crucial in the design stage because prototyping and testing costs are exceptionally high and failure is generally disastrous. As the vibratory failures generally occur in the blades, most of the researches are concentrated on the blade vibrations. Bending and torsional vibrations of the shaft are also treated in the literature as other important sources of vibration failure. However, vibrations of different elements are generally considered separately, overlooking thus possible coupling effects, though the few works considering the coupling, pointed to serious interaction between shaft and blade vibrations. The aim of this study is to study the coupling effects between shaft torsional and blade in-plane bending vibrations in single and multi stage rotor-blade systems through an analytical approach. For this purpose, an idealized model, that consists in a torsionally elastic shaft carrying a number of rigid disks, which in turn, carry a number of identical blades modelled as cantilevered, uniform Euler-Bernouilli beams is considered. The equations of this multi body system is derived through a synthetical (elements of the system are considered first), multiframe (the motion of each element is referred to the most appropriate frame) and mixed (each element is modelled by a different method) approach. Thus, the torsionally elastic shaft is modelled by finite element method to obtain a discrete model and the blades are modelled by Galerkin's method to obtain a similar model. The resulting equations of motion are linear in shaft's torsional coordinates, nonlinear in blades' bending coordinates, and include both linear and nonlinear coupling between them. A consistent small vibrations assumption leads to a fully linear model. Then, the resulting linearized equations are brought together into a single hyper-matrix-vector equation whose matrices have repetitive structures owing to the identity of the blades on each stage. The related eigenvalue analysis problem is developed analytically and splitted into two independent sub-problems corresponding to two kinds of possible normal mode motions of the system. These are referred to as coupled shaft torsion-blade bending modes and rigid shaft modes by the authors. …
ACCESSION #
49548105

 

Related Articles

  • Effect of Non-Uniform Temperature Gradients on the Onset of Convection in a Couple-Stress Fluid-Saturated Porous Medium. Shivakumara, I. S.; Sureshkumar, S.; Devaraju, N. // Journal of Applied Fluid Mechanics;Jan2012, Vol. 5 Issue 1, p49 

    The effect of different forms of basic temperature gradients on the criterion for the onset of convection in a layer of an incompressible couple-stress fluid-saturated porous medium is investigated. It is shown that the principle of exchange of stability is valid, and the eigenvalue problem is...

  • Nonlinear coupled dynamics of liquid-filled spherical container in microgravity. Bao-zeng Yue // Applied Mathematics & Mechanics;Aug2008, Vol. 29 Issue 8, p1085 

    Nonlinear coupled dynamics of a liquid-filled spherical container in microgravity are investigated. The governing equations of the low-gravity liquid sloshing in a convex axisymmetrical container subjected to lateral excitation is obtained by the variational principle and solved with a modal...

  • On computing eigenvalues of second-order linear pencils. Annaby, M. H.; Tharwat, M. M. // IMA Journal of Numerical Analysis;Apr2007, Vol. 27 Issue 2, p366 

    In this paper, we use sinc techniques to compute the eigenvalues of a second-order operator pencil of the form Q � ?P approximately. Here Q and P are self-adjoint differential operators of the second and first order, respectively. Also the eigenparameter appears in the boundary conditions...

  • Galerkin analysis of kinematic dynamos in the von Kármán geometry. Marié, L.; Normand, C.; Daviaud, F. // Physics of Fluids;Jan2006, Vol. 18 Issue 1, p017102 

    We investigate dynamo action by solving the kinematic dynamo problem for velocity fields of the von Kármán type between two coaxial counter-rotating propellers in a cylinder. A Galerkin method is implemented that takes advantage of the symmetries of the flow and their subsequent influence...

  • Effect of Bearing Dynamic Properties on the Lateral Vibration of a Flexible Rotor. Wu, Helen // Applied Mechanics & Materials;2014, Issue 553, p693 

    Analytic study of rotor vibration plays an important role in design, and fault detection and diagnosis of rotating machines. In this paper, vibration characteristics of a flexible rotor due to a central mass unbalance were analysed numerically under two cases. In Case I, bearings have symmetric,...

  • Nonlinear Vibrations of FGM Cylindrical Panel with Simply Supported Edges in Air Flow. Hao, Y. X.; Zhang, W.; Li, S. B.; Zhang, J. H. // International Journal of Aerospace Engineering;1/6/2015, Vol. 2015, p1 

    Chaotic and periodic motions of an FGM cylindrical panel in hypersonic flow are investigated. The cylindrical panel is also subjected to in-plane external loads and a linear temperature variation in the thickness direction. The temperature dependent material properties of panel which are assumed...

  • Coupling Vibration Research of a Turbine Blade-Disc System with Symmetric-Acyclic Structure. Yi Zhang; Pu Zhou; Qiang Zhang; Yonghui Xie // Applied Mechanics & Materials;2014, Issue 670-671, p1112 

    The blade-disc in a turbine is characterized by symmetric-acyclic opening structure on the disc body. Four different numerical models with 3-D finite element method were established in the present investigation. The wave propagation technique was employed and the modal analysis of the blade disc...

  • Experimental-numerical investigation of the dynamic stability of flexural-torsional vibrations of compressor blades under conditions of attached and separated flow. part 3. mutual aerodynamic couplings. Stel'makh, A. L.; Zinkovskii, A. P.; Stel'makh, Ya. A. // Strength of Materials;May2010, Vol. 42 Issue 3, p304 

    The paper considers the results of a study of mutual aerodynamic couplings which give rise to nonstationary aerodynamic interactions between the translational and angular components displacements of neighboring ring blades in the case of variation of attack angle, reduced vibration frequency and...

  • A staggered discontinuous Galerkin method for the curl–curl operator. Chung, Eric T.; Lee, Chak Shing // IMA Journal of Numerical Analysis;Jul2012, Vol. 32 Issue 3, p1241 

    This paper is concerned with a staggered discontinuous Galerkin method for the curl–curl operator arising from the time-harmonic Maxwell equations. One distinctive feature of the method is that the discrete operators preserve the properties of the differential operators. Moreover, the...

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics