Vibration Localization in Rotating Shafts: Part II — Experiment

1995 ◽  
Author(s):  
A. Galip Ulsoy ◽  
Christophe Pierre ◽  
Suhyun Choi
Keyword(s):  
Cross Section ◽  
Circular Cross Section ◽  
Companion Paper ◽  
Rotating Shaft ◽  
Vibration Localization ◽  
State Response ◽  
Mass Unbalance ◽  
Rotating Shafts ◽  
Principal Directions ◽  
Gyroscopic Coupling

Abstract This paper presents an experimental study of vibration localization in single-span, flexible, rotating shafts. It was shown in a companion paper (Part I) that a non-circular cross-section of the rotating shaft, leading to dissimilar lateral moments of inertia, can introduce disorder. Internal coupling between the principal directions of vibration is provided by the rotational speed through the gyroscopic moments. It is experimentally demonstrated here that directional vibration localization can occur for certain appropriate combinations of disorder and coupling. The steady state response, due to mass unbalance, of a simply supported rotating shaft is considered. It is shown that disorder and gyroscopic coupling lead to directional vibration localization; i.e., larger vibration amplitudes in one of the two orthogonal principal directions of the shaft cross section.

Vibration Localization in Rotating Shafts, Part 2: Experiment

1998 ◽  
Vol 120 (1) ◽  
pp. 149-155
Author(s):  
A. Galip Ulsoy ◽  
Christophe Pierre ◽  
Suhyun Choi
Keyword(s):  
Cross Section ◽  
Companion Paper ◽  
Rotating Shaft ◽  
Vibration Localization ◽  
State Response ◽  
Mass Unbalance ◽  
Rotating Shafts ◽  
Principal Directions ◽  
Gyroscopic Coupling ◽  
Internal Coupling

This paper presents an experimental study of vibration localization in single-span, flexible, rotating shafts. It was shown in a companion paper (Part I) that a noncircular cross-section of the rotating shaft, leading to dissimilar lateral moments of inertia, can introduce disorder. Internal coupling between the principal directions of vibration is provided by the rotational speed through the gyroscopic moments. It is experimentally demonstrated here that directional vibration localization can occur for appropriate combinations of disorder and coupling. The steady state response, due to mass unbalance, of a simply supported rotating shaft is considered. It is shown that disorder and gyroscopic coupling lead to directional vibration localization; i.e., larger vibration amplitudes in one of the two orthogonal principal directions of the shaft cross section.

Vibration Localization in Rotating Shafts: Part I — Theory

1995 ◽  
Author(s):  
A. Galip Ulsoy ◽  
Christophe Pierre ◽  
Suhyun Choi
Keyword(s):  
Cross Section ◽  
Rotational Speed ◽  
Theoretical Study ◽  
Circular Cross Section ◽  
Rotating Shaft ◽  
Vibration Localization ◽  
Rotating Shafts ◽  
Principal Directions ◽  
Internal Coupling ◽  
Perturbation Solutions

Abstract This paper presents a theoretical study of vibration localization in single-span, flexible, rotating shafts. A non-circular cross-section of the rotating shaft, leading to dissimilar lateral moments of inertia, can introduce disorder. Internal coupling between the principal directions of vibration is provided by the rotational speed through the gyroscopic moments. It is shown, using both exact and perturbation solutions, that directional vibration localization can occur for certain appropriate combinations of disorder and coupling.

Vibration Localization in Rotating Shafts, Part 1: Theory

1998 ◽  
Vol 120 (1) ◽  
pp. 138-148 ◽  
Author(s):  
A. Galip Ulsoy ◽  
Christophe Pierre ◽  
Suhyun Choi
Keyword(s):  
Cross Section ◽  
Rotational Speed ◽  
Theoretical Study ◽  
Rotating Shaft ◽  
Moments Of Inertia ◽  
Vibration Localization ◽  
Noncircular Cross Section ◽  
Rotating Shafts ◽  
Principal Directions ◽  
Internal Coupling

This paper presents a theoretical study of vibration localization in single-span, flexible, rotating shafts. A noncircular cross-section of the rotating shaft, leading to dissimilar lateral moments of inertia, can introduce disorder. Internal coupling between the principal directions of vibration is provided by the rotational speed through the gyroscopic moments. It is shown, both analytically and numerically, that directional vibration localization can occur for certain appropriate combinations of disorder and coupling.

Weight-Excited Vibrations of Rotating Curved Beams

1991 ◽  
Author(s):  
Jörg Wauer
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Nonlinear Boundary ◽  
Circular Cross Section ◽  
Rotational Axis ◽  
Curved Beams ◽  
Rotating Beam ◽  
Chaotic Motions ◽  
State Response ◽  
Modal Truncation

Abstract Flexural vibrations of a slender rotating beam whose centre line is assumed to be naturally curved are considered. The beam, simply supported and axially restrained rotates at a constant speed about a horizontal axis in a gravity field. In one case, the rotational axis is parallel to the line connecting the centroids of the end cross-sections, and, in the other case, it is perpendicular to that line. A modal truncation of the governing nonlinear boundary value problem yields a set of ordinary gyroscopic differential equations of the Duffing type. For the cases of a cross-section with extremely different bending stiffnesses and a circular cross-section, the vibrational behaviour is analyzed in detail. The steady-state response (neglecting the influence of gravity) and its stability are considered first. A numerical investigation of weight-excited oscillations follows, where both periodic and even chaotic motions may occur. The effect of different damping mechanisms is addressed. A comparison with the dynamic snap-through of a non-rotating arch and the nonlinear vibrations of a rotating straight bar concludes the contribution.

Dynamic Analysis of High-Speed Rotating Shafts Using the Flexible Multibody Approach

2018 ◽  
Author(s):  
Vesa-Ville Hurskainen ◽  
Babak Bozorgmehri ◽  
Marko K. Matikainen ◽  
Aki Mikkola
Keyword(s):  
Dynamic Analysis ◽  
Cross Section ◽  
High Speed ◽  
Capture Cross Section ◽  
Absolute Nodal Coordinate Formulation ◽  
Beam Element ◽  
Capture Cross ◽  
Rotating Shaft ◽  
Absolute Nodal Coordinate ◽  
Rotating Shafts

In this study, a higher-order finite element based on the absolute nodal coordinate formulation (ANCF) is applied in the dynamic analysis of high-speed rotating shafts. Static and modal tests are carried out to analyze the performance and accuracy of the introduced ANCF element. Also, via a transient dynamic benchmark test involving a rotating flexible shaft, the accuracy of the examined beam element in high-speed applications is analyzed. According to the results, the introduced beam element can adequately capture cross-section deformationin high-speed rotating shaft analysis.

scholarly journals Influence of rotatory inertia on stochastic stability of a viscoelastic rotating shaft

2008 ◽  
Vol 35 (4) ◽  
pp. 363-379
Author(s):  
Ratko Pavlovic ◽  
P. Kozic ◽  
G. Janevski
Keyword(s):  
Cross Section ◽  
Stochastic Stability ◽  
Circular Cross Section ◽  
Longitudinal Axis ◽  
Physical Parameters ◽  
Rotatory Inertia ◽  
Rotating Shaft ◽  
Axial Forces ◽  
Constant Rate ◽  
Mean And Variance

The stochastic stability problem of a viscoelastic Voigt-Kelvin balanced rotating shaft subjected to action of axial forces at the ends is studied. The shaft is of circular cross-section, it rotates at a constant rate about its longitudinal axis of symmetry. The effect of rotatory inertia of the shaft cross-section and external viscous damping are included into account. The force consists of a constant part and a time-dependent stochastic function. Closed form analytical solutions are obtained for simply supported boundary conditions. By using the direct Liapunov method almost sure asymptotic stability conditions are obtained as the function of stochastic process variance, external damping coefficient, retardation time, angular velocity, and geometric and physical parameters of the shaft. Numerical calculations are performed for the Gaussian process with a zero mean and variance ?2 as well as for harmonic process with amplitude H.

SAF file: It's really three dimensional file

2018 ◽  
Vol 14 (1) ◽  
pp. 1
Author(s):  
Prof. Dr. Jamal Aziz Mehdi
Keyword(s):  
Cross Section ◽  
Root Canal ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Circular Motion ◽  
Root Canal Treatment ◽  
Metal Core ◽  
Rotating Blade

The biological objectives of root canal treatment have not changed over the recentdecades, but the methods to attain these goals have been greatly modified. Theintroduction of NiTi rotary files represents a major leap in the development ofendodontic instruments, with a wide variety of sophisticated instruments presentlyavailable (1, 2).Whatever their modification or improvement, all of these instruments have onething in common: they consist of a metal core with some type of rotating blade thatmachines the canal with a circular motion using flutes to carry the dentin chips anddebris coronally. Consequently, all rotary NiTi files will machine the root canal to acylindrical bore with a circular cross-section if the clinician applies them in a strictboring manner

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