Mode Localization of a Cracked Blade Disk

1999 ◽  
Vol 121 (2) ◽  
pp. 335-341 ◽  
Author(s):  
J. H. Kuang ◽  
B. W. Huang
Keyword(s):  
Equations Of Motion ◽  
Crack Depth ◽  
Numerical Results ◽  
Rotating System ◽  
Mode Localization ◽  
Rotating Speed ◽  
Rotating Blade ◽  
Localization Phenomenon ◽  
Blade Crack ◽  
Plane Mode

In this paper, the effect of blade crack on the mode localization of a rotating blade disk is studied. Pretwisted taper beams are used to simulate blades of a blade disk. The crack on the blade can be regarded as a local disorder of this periodically coupled blades system. An application of Hamilton’s principle and Galerkin’s method is used to formulate the equations of motion of the mistuned system. Effects of pretwisted angle, rotating speed, and crack depth of the blade on the in-plane and off-plane mode localizations of a rotating system are investigated. Numerical results indicate that the increase of rotating speed, pretwisted angle, and crack depth could enhance the localization phenomenon significantly.

scholarly journals Mode Localization of a Cracked Blade-Disks

1998 ◽  
Author(s):  
J. H. Kuang ◽  
B. W. Huang
Keyword(s):  
Equations Of Motion ◽  
Crack Depth ◽  
Numerical Results ◽  
Rotating System ◽  
Mode Localization ◽  
Rotating Speed ◽  
Rotating Blade ◽  
Localization Phenomenon ◽  
Blade Crack ◽  
Plane Mode

In this paper, the effect of blade crack on the mode localization of a rotating blade-disk is studied. Pretwisted taper beams are used to simulate blades of a blade-disk. The crack on the blade can be regarded as a local disorder of this periodically coupled blades system. An application of Hamilton’s principle and Galerkin’s method is used to formulate the equations of motion of the mistuned system. Effects of pretwisted angle, rotating speed and crack depth of the blade on the in-plane and off-plane mode localizations of a rotating system are investigated. Numerical results indicate that the increase of rotating speed, pretwisted angle and crack depth could enhance the localization phenomenon significantly.

Effect of a local crack on the dynamic characteristics of a rotating grouped blade disc

2001 ◽  
Vol 216 (4) ◽  
pp. 447-457 ◽  
Author(s):  
B W Huang ◽  
J H Kuang
Keyword(s):  
Dynamic Characteristics ◽  
Rotational Speed ◽  
Crack Depth ◽  
Numerical Results ◽  
Galerkin’S Method ◽  
Mode Localization ◽  
Torsion Spring ◽  
Crack Distribution ◽  
Localization Phenomenon ◽  
Blade Crack

The effects of a local blade crack and the group arrangement on the mode localization in a rotating turbodisc are studied in this paper. Periodically coupled Euler—Bernoulli beams are used to approximate the grouped and shrouded turboblades. A two-span beam with a torsion spring is used to model the cracked blade. The crack depth characterizes the stiffness of the assumed torsion spring. Galerkin's method is applied to formulate the localization equations of the grouped turbodisc system. Numerical results indicate that the crack depth, crack distribution and rotational speed in a rotating grouped blade disc may significantly affect the localization phenomenon.

Mode Localization in a Grouped Bladed Disk

2000 ◽  
Author(s):  
J. H. Kuang ◽  
B. W. Huang
Keyword(s):  
Galerkin Method ◽  
Rotation Speed ◽  
Numerical Results ◽  
Mode Localization ◽  
Crack Distribution ◽  
Bladed Disk ◽  
Localization Phenomenon ◽  
Blade Assembly ◽  
The Galerkin Method ◽  
Blade Crack

The effect of local blade crack on the mode localization in a rotating turbo disk with a group-blade assembly was studied. Periodically coupled Euler-Bernoulli beams were used to approximate the grouped and shrouded turbo blades. The cracked blade, regardedas a local disorder, was modeled using a two-span beam. A spring was imposed on this two-span beam to characterize the local crack. The Galerkin method was applied to formulate the localization equations of the mistuned system. Numerical results indicate that the blade crack, crack distribution and rotation speed in a rotating group-blades disk may affect the localization phenomenon significantly.

scholarly journals On The Vibration of a Cracked Rotating Blade

1998 ◽  
Vol 5 (5-6) ◽  
pp. 317-323 ◽  
Author(s):  
Ming-Chuan Wu ◽  
Shyh-Chin Huang
Keyword(s):  
Natural Frequencies ◽  
Equations Of Motion ◽  
Crack Depth ◽  
Weighted Residual Method ◽  
Energy Principle ◽  
Discrete Equations ◽  
Rotating Blade ◽  
On Line ◽  
Released Energy ◽  
Blade Frequency

The dynamic behavior of a rotating blade containing a transverse crack was investigated. First, the local flexibility of the cracked blade was obtained by using the method of the released energy. An energy principle, in conjunction with a weighted residual method, was then applied to yield the discrete equations of motion. The equations of motion were further utilized to study the influences of the crack depth and location on the bending natural frequencies under various of rotation speeds. The numerical calculation showed that the crack effects the natural frequencies and the response appreciably only if it is relatively deep and locates near the root of the blade. However, the effects increase exponentially with the depth increases. In addition to the natural frequencies, the displacement responses of the blade with a crack under a constant lateral forces were discussed as well. This was done by calculating the deflections at the tip of the blade for various crack depths and locations. Similar to the rotation speed of the blade frequency, the deflection was offset by the increase of the rotation. However, the centrifugal effects increased significantly such that the crack’s effects became relatively insignificant. Nevertheless, the study showed that the changes on the natural frequency and the tip-deflection of the blade due to a crack may be used as indices for on-line detection of cracks.

Coriolis Effect on Mode Localization in a Rotating Bladed Disk

1997 ◽  
Author(s):  
J. H. Kuang ◽  
B. W. Huang
Keyword(s):  
Coriolis Force ◽  
Disk System ◽  
Mode Localization ◽  
Bladed Disk ◽  
Rotating Blade ◽  
Localization Phenomenon ◽  
Weakly Coupled ◽  
Lateral Modes ◽  
Speed Effect ◽  
Modal Coordinates

Abstract An investigation of the speed effect, i.e., the effects of centrifugal force and coriolis force, on the mode localization of a mistuned blade-disk is presented in this paper. A disk comprising of periodically shrouded blades is used to simulate the weakly coupled periodic structure. Galerkin method is employed to derive the mode localization equations of the mistuned system with the consideration of coriolis force. The blades are approximated as cantilever beams, and five axial and lateral modes of each blade are used to present the dynamic behavior of the system. Ten modal coordinates have been considered for each blade. The effects of coriolis force and the magnitude of disorder on the localization phenomenon of a rotating blade-disk system were investigated numerically. Numerical results obtained herein indicate that the coriolis force may enhance the localization phenomenon.

scholarly journals Dynamic Stability in a Cracked Turbo Blade-Disk

1999 ◽  
Author(s):  
J. H. Kuang ◽  
B. W. Huang
Keyword(s):  
Multiple Scales ◽  
Rotation Speed ◽  
Equations Of Motion ◽  
Crack Depth ◽  
Disk System ◽  
Rotating Blade ◽  
Blade System ◽  
Instability Regions ◽  
The Stability ◽  
Multiple Scales Perturbation Method

Analysis of the stability in a cracked blade-disk system is proposed. The effect of modal localization on the stability in a rotating blade-disk was studied. A crack near the root of a blade is regarded as a local disorder in this periodically coupled blade system. Hamilton’s principle and Galerkin’s method were used to formulate the equations of motion for the cracked blade-disk. The instability regions of this cracked blade-disk system were specified by employing the multiple scales perturbation method. Numerical results indicate that the rotation speed, shroud stiffness and crack depth in the blades affect the stability regions of this mistuned system significantly.

Nonlinear Behavior of a Disc-Shaft Rotating System With a Transverse Crack

2006 ◽  
Author(s):  
Liming Dai ◽  
Changping Chen
Keyword(s):  
Geometric Nonlinearity ◽  
Transverse Crack ◽  
Chaotic Behavior ◽  
Crack Depth ◽  
Nonlinear Behavior ◽  
Rotating System ◽  
Rotating Speed ◽  
The Masses ◽  
Cracked Shaft

This research intends to investigate the nonlinear behavior of a rotating system with a cracked shaft mounted with a disc. Effects of the geometric nonlinearity, the masses of the shaft and disc and the viscoelastic supports of the rotating system on the motion of the system are studied. The characteristics of the system, such as bifurcations, periodic, quasiperiodic and chaotic behavior are evaluated. Effects of crack depth and rotating speed on the nonlinear behavior of the system are also investigated.

scholarly journals A study on the vibration dissipation mechanism of the rotating blade with dovetail joint

2021 ◽  
pp. 146134842098533
Author(s):  
Chaofeng Li ◽  
Zengchuang Shen ◽  
Zilin Chen ◽  
Houxin She
Keyword(s):  
Dry Friction ◽  
Vibration Reduction ◽  
Friction Model ◽  
Rotating Speed ◽  
System Parameters ◽  
Tangential Stiffness ◽  
Damping Characteristics ◽  
Rotating Blade ◽  
Spatial Beam ◽  
Dissipation Mechanism

The vibration dissipation mechanism of the rotating blade with a dovetail joint is studied in this paper. Dry friction damping plays an indispensable role in the direction of vibration reduction. The vibration level is reduced by consuming the total energy of the turbine blade with the dry friction device on the blade-root in the paper. The mechanism of the vibration reduction is revealed by the variation of the friction force and the energy dissipation ratio of dry friction. In this paper, the flexible blade with a dovetail interface feature is discretized by using the spatial beam element based on the finite element theory. Then the classical Coulomb-spring friction model is introduced to obtain the dry friction model on the contact interfaces of the tenon-mortise structure. What is more, the effects of the system parameters (such as the rotating speed, the friction coefficient, the installation angle of the tenon) and the excitation level on blade damping characteristics are discussed, respectively. The results show that the variation of the system parameters leads to a significant change of damping characteristics of the blade. The variation of the tangential stiffness and the position of the external excitation will affect the nonlinear characteristics and vibration damping characteristics.

Nonlinear Vibrations of Two-Span Composite Laminated Plates with Equal and Unequal Subspan Lengths

2017 ◽  
Vol 9 (6) ◽  
pp. 1485-1505
Author(s):  
Lingchang Meng ◽  
Fengming Li
Keyword(s):  
Multiple Scales ◽  
Equations Of Motion ◽  
Primary Resonance ◽  
Laminated Plates ◽  
Laminated Plate ◽  
Composite Laminated Plate ◽  
Vibration Localization ◽  
Composite Laminated Plates ◽  
Localization Phenomenon ◽  
Harmonic Resonance

AbstractThe nonlinear transverse vibrations of ordered and disordered two-dimensional (2D) two-span composite laminated plates are studied. Based on the von Karman's large deformation theory, the equations of motion of each-span composite laminated plate are formulated using Hamilton's principle, and the partial differential equations are discretized into nonlinear ordinary ones through the Galerkin's method. The primary resonance and 1/3 sub-harmonic resonance are investigated by using the method of multiple scales. The amplitude-frequency relations of the steady-state responses and their stability analyses in each kind of resonance are carried out. The effects of the disorder ratio and ply angle on the two different resonances are analyzed. From the numerical results, it can be concluded that disorder in the length of the two-span 2D composite laminated plate will cause the nonlinear vibration localization phenomenon, and with the increase of the disorder ratio, the vibration localization phenomenon will become more obvious. Moreover, the amplitude-frequency curves for both primary resonance and 1/3 sub-harmonic resonance obtained by the present analytical method are compared with those by the numerical integration, and satisfactory precision can be obtained for engineering applications and the results certify the correctness of the present approximately analytical solutions.

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