Pseudo Static Excitation of Turbine Blades Under Acceleration

1995 ◽  
Author(s):  
Nalinaksh S. Vyas
Keyword(s):  
Cross Section ◽  
Equations Of Motion ◽  
Turbine Blades ◽  
Angular Acceleration ◽  
Vibration Response ◽  
Response Patterns ◽  
Governing Equations ◽  
Coriolis Forces ◽  
Lagrangian Equations ◽  
Stagger Angle

Abstract Coriolis forces, on a blade mounted on a disc rotating with angular acceleration, give rise to a pseudo static excitation to the blade. The resulting vibrations are simultaneously influenced by the changing stiffness of the blade under acceleration. The occurrence of this shock phenomenon has been reported in earlier studies for uniform beams. In this paper the phenomenon is investigated for a typical tapered, pretwisted, turbine lade with an asymmetric aerofoil cross section and mounted on the disc at a stagger angle. The governing equations of motion, for uniform rates of acceleration are derived employing Lagrangian equations. The vibration response patterns of the blade, obtained numerically, for typical acceleration rates are illustrated.

Structural Dynamics Analysis of Rotating Blades Using Fully Intrinsic Equations, Part I: Formulation and Verification of Single-Load-Path Configurations

2013 ◽  
Vol 58 (3) ◽  
pp. 1-9 ◽  
Author(s):  
Zahra Sotoudeh ◽  
Dewey H. Hodges
Keyword(s):  
Structural Dynamics ◽  
Equations Of Motion ◽  
Turbine Blades ◽  
Rotor Blades ◽  
Load Path ◽  
Dynamics Modeling ◽  
Governing Equations ◽  
Wind Turbine Blades ◽  
First Order ◽  
Infinite Degree

As part of an ongoing investigation into potential advantages of so-called fully intrinsic formulations, this paper presents an application of the fully intrinsic equations of motion and kinematics for beams to rotor blades. A fully intrinsic formulation is devoid of displacement and rotation variables. Although the governing equations are geometrically exact, they are free of the attendant singularities and infinite-degree nonlinearities found in other types of formulations. These nonlinear, first-order partial differential equations are suitable for analyzing initially curved and twisted, anisotropic beams and thus are very attractive for analysis of both helicopter and wind turbine blades. This two-part paper is devoted to the structural dynamics modeling of rotor blades with a wide variety of boundary conditions—in particular hingeless and bearingless rotor configurations. In Part I, the theory and the formulation are presented, along with verification of single-load-path configurations. Part II is devoted to the verification of dual-load-path configurations.

Structural Dynamics Analysis of Rotating Blades Using Fully Intrinsic Equations, Part II: Dual-Load-Path Configurations

2013 ◽  
Vol 58 (3) ◽  
pp. 1-9 ◽  
Author(s):  
Zahra Sotoudeh ◽  
Dewey H. Hodges
Keyword(s):  
Structural Dynamics ◽  
Equations Of Motion ◽  
Turbine Blades ◽  
Rotor Blades ◽  
Load Path ◽  
Dynamics Modeling ◽  
Governing Equations ◽  
Wind Turbine Blades ◽  
First Order ◽  
Infinite Degree

As part of an ongoing investigation into potential advantages of so-called fully intrinsic formulations, this paper presents an application of the fully intrinsic equations of motion and kinematics for beams to rotor blades. A fully intrinsic formulation is devoid of displacement and rotation variables. Although the governing equations are geometrically exact, they are free of the attendant singularities and infinite-degree nonlinearities found in other types of formulations. These nonlinear, first-order partial differential equations are suitable for analyzing initially curved and twisted, anisotropic beams and thus are very attractive for analysis of both helicopter and wind turbine blades. This two-part paper is devoted to the structural dynamics modeling of rotor blades with a wide variety of boundary conditions—in particular hingeless and bearingless rotor configurations. Part II is devoted to verification of certain dual-load-path configurations suggested by Bell Helicopter Textron.

Blade Mistuning Coupled With Shaft Flexibility Effects in Rotor Aeroelasticity

1989 ◽  
Author(s):  
Naim Khader ◽  
Robert G. Loewy
Keyword(s):  
Equations Of Motion ◽  
Governing Equations ◽  
Aeroelastic Stability ◽  
Stability Boundaries ◽  
Coriolis Forces ◽  
Bladed Disk ◽  
Out Of Plane ◽  
Shaft Flexibility ◽  
Rotor Aeroelasticity ◽  
Plane Deformations

The effect of bladed-disk polar dissymmetry, resulting from variations in mass from one blade to another, on aeroelastic stability boundaries for a fan stage is presented. In addition to both in-plane and out-of-plane deformations of the bladed-disk, bending of the supporting shaft in two planes is considered, and the resulting Coriolis forces and gyroscopic moments are included in the analysis. A quasi-steady aerodynamics approach is combined with the Lagrangian method to develop the governing equations of motion for the flexible bladed-disk-shaft assembly. Calculations are performed for an actual fan stage.

Simulation of Engine Vibration on Nonlinear Hydraulic Engine Mounts

2005 ◽  
Author(s):  
A. R. Ohadi ◽  
G. Maghsoodi
Keyword(s):  
Equations Of Motion ◽  
Low Frequency ◽  
Governing Equations ◽  
Engine Mounts ◽  
Engine Vibration ◽  
Engine Mount ◽  
Rotational Motions ◽  
The Time Domain ◽  
Nonlinear Equations Of Motion ◽  
Four Cylinders

In this paper, vibration behavior of engine on nonlinear hydraulic engine mount including inertia track and decoupler is studied. In this regard, after introducing the nonlinear factors of this mount (i.e. inertia and decoupler resistances in turbulent region), the vibration governing equations of engine on one hydraulic engine mount are solved and the effect of nonlinearity is investigated. In order to have a comparison between rubber and hydraulic engine mounts, a 6 degree of freedom four cylinders V-shaped engine under inertia and balancing masses forces and torques is considered. By solving the time domain nonlinear equations of motion of engine on three inclined mounts, translational and rotational motions of engines body are obtained for different engine speeds. Transmitted base forces are also determined for both types of engine mount. Comparison of rubber and hydraulic mounts indicates the efficiency of hydraulic one in low frequency region.

Regeneration-Induced Forced Response in Axial Turbines

2013 ◽  
Author(s):  
Jens Aschenbruck ◽  
Christopher E. Meinzer ◽  
Linus Pohle ◽  
Lars Panning-von Scheidt ◽  
Joerg R. Seume
Keyword(s):  
Turbine Blades ◽  
Forced Response ◽  
Response Analysis ◽  
Geometrical Parameters ◽  
Turbine Stage ◽  
Structural Dynamic ◽  
Air Turbine ◽  
Axial Turbines ◽  
Interaction Approach ◽  
Stagger Angle

The regeneration of highly loaded turbine blades causes small variations of their geometrical parameters. To determine the influence of such regeneration-induced variances of turbine blades on the nozzle excitation, an existing air turbine is extended by a newly designed stage. The aerodynamic and the structural dynamic behavior of the new turbine stage are analyzed. The calculated eigenfrequencies are verified by an experimental modal analysis and are found to be in good agreement. Typical geometric variances of overhauled turbine blades are then applied to stator vanes of the newly designed turbine stage. A forced response analysis of these vanes is conducted using a uni-directional fluid-structure interaction approach. The effects of geometric variances on the forced response of the rotor blade are evaluated. It is shown that the vibration amplitudes of the response are significantly higher for some modes due to the additional wake excitation that is introduced by the geometrical variances e.g. 56 times higher for typical MRO-induced variations in stagger-angle.

Reduction of Noise Inside a Cavity by Piezoelectric Actuators

2003 ◽  
Vol 125 (1) ◽  
pp. 12-17 ◽  
Author(s):  
I. Hagiwara ◽  
D. W. Wang ◽  
Q. Z. Shi ◽  
R. S. Rao
Keyword(s):  
Sound Pressure ◽  
Control Mechanism ◽  
Equations Of Motion ◽  
Piezoelectric Actuators ◽  
Governing Equations ◽  
Control Laws ◽  
Modal Coupling ◽  
Modal Amplitude ◽  
Global And Local ◽  
Fully Coupled

A new analytical model is developed for the reduction of noise inside a cavity using distributed piezoelectric actuators. A modal coupling method is used to establish the governing equations of motion of the fully coupled acoustics-structure-piezoelectric patch system. Two performance functions relating “global” and “local” optimal control of sound pressure levels (SPL) respectively are applied to obtain the control laws. The discussions on associated control mechanism show that both the mechanisms of modal amplitude suppression and modal rearrangement may sometimes coexist in the implementation of optimal noise control.

Influence of Material Damping on In-Plane Modal Parameters for Rotating Disks

2012 ◽  
Author(s):  
Hamid R. Hamidzadeh ◽  
Ehsan Sarfaraz
Keyword(s):  
Elastic Moduli ◽  
Damping Ratio ◽  
Equations Of Motion ◽  
Elastic Stability ◽  
Rotating Disks ◽  
Governing Equations ◽  
Annular Disk ◽  
Stress Theory ◽  
Hysteretic Damping ◽  
Circumferential Wave

The linear in-plane free vibration of a thin, homogeneous, viscoelastic, rotating annular disk is investigated. In the development of an analytical solution, two dimensional elastodynamic theory is employed and the viscoelastic material for the medium is allowed by assuming complex elastic moduli. The general governing equations of motion are derived by implementing plane stress theory. Natural frequencies are computed for several modes at specific radius ratios with fixed-free boundary conditions and modal loss factors for different damping ratios are determined. The computed results were compared to previously established results. It was observed that the effects of rotational speed and hysteretic damping ratio on natural frequency and elastic stability of the rotating disks were related to the mode of vibration and type of circumferential wave occurring.

scholarly journals Conducting dusty fluid flow through a constriction in a porous medium

2016 ◽  
Vol 5 (1) ◽  
pp. 29
Author(s):  
Madhura K R ◽  
Uma M S
Keyword(s):  
Porous Medium ◽  
Hartmann Number ◽  
Equations Of Motion ◽  
Fluid Phase ◽  
Dust Particles ◽  
Governing Equations ◽  
Electrically Conducting ◽  
Electrically Conducting Fluid ◽  
Flow Through ◽  
Constricted Channel

<p><span lang="EN-IN">The flow of an unsteady incompressible electrically conducting fluid with uniform distribution of dust particles in a constricted channel has been studied. The medium is assumed to be porous in nature. The governing equations of motion are treated analytically and the expressions are obtained by using variable separable and Laplace transform techniques. The influence of the dust particles on the velocity distributions of the fluid are investigated for various cases and the results are illustrated by varying parameters like Hartmann number, deposition thickness on the walls of the cylinder and the permeability of the porous medium on the velocity of dust and fluid phase.</span></p>

scholarly journals Eco-friendly technology of manufacturing complex products made of composites

2019 ◽  
Vol 140 ◽  
pp. 02004
Author(s):  
Aleksey Ignatov ◽  
Rustam Subkhankulov
Keyword(s):  
Composite Materials ◽  
Cross Section ◽  
Manufacturing Process ◽  
Volume Fraction ◽  
Turbine Blades ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Technological Parameters ◽  
Technological Support ◽  
The Impact

Numerous studies in application of modern composite materials show that their advantages can be successfully implemented in manufacturing «smart» products. This study proposes an improved technological method of manufacturing multilayer environmentally friendly products with a variable cross section, which allows us to expand the possibilities of using modern polymer composite materials (PCM). The technology allows manufacturing products of the most complex geometric shapes, such as wind turbine blades. The aim of the study is the technological support of engineering production in the manufacture of multilayer products of variable cross section made from PCM. Scientific novelty consists in identifying the patterns of implementation and management of the manufacturing process of multilayer products of variable cross-section, and establishing the influence of structural and technological parameters of the manufacturing process on their operational characteristics. The relationship between the pressure of a hot directed air stream and the volume fraction of pores in the hardened material of a multilayer composite product with a variable cross section during layer-by-layer application is investigated. During the study, fundamental and applied principles of mechanical engineering technology, material resistance, adhesion theory, mathematical statistics tools and software were used to process the results of the experiment. Based on the results of laboratory studies, a methodology has been developed for effective prediction of pore content in the manufacturing of composite products. The introduction of the presented technology and the corresponding original methodology into production will reduce the complexity and energy costs of manufacturing composite products, improve their quality and reduce the impact of toxic components from composite materials on workers.

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