Railway Wheel Squeal (Squeal of Disk Subjected to Periodic Excitation)

1998 ◽  
Vol 120 (2) ◽  
pp. 614-622 ◽  
Author(s):  
M. Nakai ◽  
S. Akiyama
Keyword(s):  
Natural Frequency ◽  
Wheel Running ◽  
Vibrational Mode ◽  
Axial Direction ◽  
Periodic Excitation ◽  
Fundamental Study ◽  
Nodal Diameter ◽  
Railway Wheel ◽  
Steel Disk ◽  
Thin Steel

As a fundamental study of the squeal of a railway wheel running on a corrugated rail, frictional experiments using a thin steel disk and a rod and analysis were performed. A disk representing the railway wheel was clamped at the center with a free periphery and subjected to periodic excitation in its axial direction. When the frequency of excitation is not close to any natural frequency of the disk, squeals with a single nodal diameter mode occur. Squeals at the natural frequency of the disk fall into resonance with the frequency of the excitation, provided that the two frequencies are the same. Then two kinds of squeals occur: squeal at entrained frequency and that at both the entrained frequency and the frequency of another vibrational mode of the disk.

Thermal Effects on the Natural Frequency of Nonlinear, Co-Rotating Disks

2005 ◽  
Author(s):  
Albert C. J. Luo ◽  
Nader Saniei ◽  
William Ray Harp
Keyword(s):  
Natural Frequency ◽  
Thermal Effects ◽  
Natural Frequencies ◽  
Computer Memory ◽  
Uniform Temperature ◽  
Rotating Disks ◽  
Nonlinear Free Vibration ◽  
Nodal Diameter ◽  
Disk Rotation ◽  
Asymmetric Responses

Thermal effects on the natural frequency for the nonlinear free vibration of co-rotating disks are investigated for non-uniform temperature distributions relative to airflow induced by disk rotation. The natural frequencies for symmetric and asymmetric responses of a 3.5 inch diameter computer memory disk are calculated. When the disk is heated, its stiffness becomes larger for the two lowest nodal diameter numbers and smaller for the other nodal diameter numbers. It implies that the vibration of heated, rotating disks for the higher nodal diameter numbers may be induced more easily than the cooled one.

Reduced Modeling for Turbine Rotor-Blade Coupled Bending Vibration Analysis

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
Akira Okabe ◽  
Takeshi Kudo ◽  
Koki Shiohata ◽  
Osami Matsushita ◽  
Hiroyuki Fujiwara ◽  
...  
Keyword(s):  
Natural Frequency ◽  
Rotor Blade ◽  
High Efficiency ◽  
Sliding Mode ◽  
Coupled System ◽  
Bending Vibration ◽  
Mass System ◽  
Joint Power ◽  
Nodal Diameter ◽  
Blade System

In a traditional turbine-generator set, rotor shaft designers and blade designers have their own models and design process which neglects the coupled effect. Since longer blade systems have recently been employed (Saito et al. 1998, “Development of a 3000 rpm 43-in. last stage blade with high efficiency and reliability,” International Joint Power Generation Conference, pp. 89–96.) for advanced turbine sets to get higher output and efficiency, additional consideration is required concerning rotor bending vibrations coupled with a one-nodal (k = 1) blade system. Rotor-blade coupled bending conditions generally include two types so that the parallel and tilting modes of the shaft vibrations are respectively coupled with in-plane and out-of-plane modes of blade vibrations with a one-nodal diameter (k = 1). This paper proposes a method to calculate the natural frequency of a shaft blade coupled system. According to this modeling technique, a certain blade mode is reduced to a single mass system, which is connected to the displacement and angle motions of the shaft. The former motion is modeled by the m-k system to be equivalent to the blade on the rotating coordinate. The latter motion is commonly modeled in discrete form using the beam FEM on an inertia coordinate. Eigenvalues of the hybrid system covering both coordinates provide the natural frequency of the coupled system. In order to solve the eigenfrequencies of the coupled system, a tracking solver method based on sliding mode control concept is used. An eight-blade system attached to a cantilever bar is used for an example to calculate a coupled vibration with a one-nodal diameter between the blade and shaft.

scholarly journals Bursting Oscillations in Shimizu-Morioka System with Slow-Varying Periodic Excitation

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Xindong Ma ◽  
Shuqian Cao
Keyword(s):  
Natural Frequency ◽  
Coupling Effect ◽  
Excitation Frequency ◽  
Time Interval ◽  
Periodic Excitation ◽  
Bursting Oscillations ◽  
Fold Bifurcation ◽  
Exciting Frequency ◽  
Bursting Oscillation ◽  
Parameter Condition

The coupling effect of two different frequency scales between the exciting frequency and the natural frequency of the Shimizu-Morioka system with slow-varying periodic excitation is investigated. First, based on the analysis of the equilibrium states, homoclinic bifurcation, fold bifurcation, and supercritical Hopf bifurcation are observed in the system under a certain parameter condition. When the exciting frequency is much smaller than the natural frequency, we can regard the periodic excitation as a slow-varying parameter. Second, complicated dynamic behaviors are analyzed when the slow-varying parameter passes through different bifurcation points, of which the mechanisms of four different bursting patterns, namely, symmetric “homoclinic/homoclinic” bursting oscillation, symmetric “fold/Hopf” bursting oscillation, symmetric “fold/fold” bursting oscillation, and symmetric “Hopf/Hopf” bursting oscillation via “fold/fold” hysteresis loop, are revealed with different values of the parameterbby means of the transformed phase portrait. Finally, we can find that the time interval between two symmetric adjacent spikes of bursting oscillations exhibits dependency on the periodic excitation frequency.

Maximizing the Natural Frequencies and Transverse Stiffness of Centrally damped, Circular Disks by Thickening the Clamped Part of the Disk

1999 ◽  
Vol 66 (4) ◽  
pp. 1017-1021 ◽  
Author(s):  
A. A. Renshaw
Keyword(s):  
Natural Frequency ◽  
Natural Frequencies ◽  
Vibration Modes ◽  
Rotating Disks ◽  
Design Study ◽  
Nodal Diameter ◽  
Transverse Stiffness ◽  
Vibration Data ◽  
Two Alternatives ◽  
Circular Disks

The natural frequencies and transverse stiffness of centrally damped, circular disks are computed taking into account the flexibility of the central clamp and the thickness of the damped part of the disk. When compared to experimental vibration data, these predictions are more accurate than the traditional, perfect clamping predictions, particularly, for zero and one-nodal-diameter vibration modes. The reduction in natural frequency or transverse stiffness caused by clamping flexibility can be mitigated either by increasing the clamping stiffness or by increasing the hub thickness, defined here as the thickness of the disk sandwiched by the central clamp. A design study of these two alternatives for both stationary and rotating disks shows that increasing the hub thickness is often a more attractive design alternative.

Estimation of railway wheel running temperatures using a hybrid approach

Wear ◽  
2015 ◽  
Vol 328-329 ◽  
pp. 537-551 ◽  
Author(s):  
M.R.K. Vakkalagadda ◽  
K.P. Vineesh ◽  
V. Racherla
Keyword(s):  
Wheel Running ◽  
Hybrid Approach ◽  
Railway Wheel

scholarly journals Computer aided simulation analysis for wear investigation of railway wheel running surface

Diagnostyka ◽  
2019 ◽  
Vol 20 (3) ◽  
pp. 63-68
Author(s):  
Paweł Drozdziel ◽  
Pavol Stastniak ◽  
Lukas Smetanka
Keyword(s):  
Simulation Analysis ◽  
Wheel Running ◽  
Railway Wheel ◽  
Computer Aided

A New Solution Method for Vibration Analysis of Circular Cylindrical Thin Shells with a Circumferential Surface Crack

2013 ◽  
Vol 639-640 ◽  
pp. 1003-1009 ◽  
Author(s):  
Tao Yin ◽  
Dian Qing Li ◽  
Hong Ping Zhu
Keyword(s):  
Boundary Conditions ◽  
Natural Frequency ◽  
Thin Shell ◽  
Solution Method ◽  
Cylindrical Shells ◽  
Axial Direction ◽  
Mode Shapes ◽  
Governing Equations ◽  
Simply Supported ◽  
Initial Trial

In this paper, a new solution method is proposed for determining the natural frequency of a given mode for a finite-length circular cylindrical thin shell with a circumferential part-through crack. The governing equation of the cracked cylindrical shell is derived by integrating the line-spring model with the classical thin shell theory. The proposed method calculates the natural frequency from an initial trial to satisfy both the governing equations and appropriate boundary conditions through an optimization process. The initial trial is proposed to satisfy the governing equations by using the beam modal function to determine the modal wavenumbers and mode shapes of cylindrical shells in the axial direction, assuming the flexural mode shapes of cylindrical shells in the axial direction to be of the same form as that of a flexural vibration beam with the same boundary conditions. Four representative sets of boundary conditions are considered: simply supported (SS-SS), clamped-clamped (C-C), clamped-simply supported (C-SS), and clamped-free (C-F). Compared with the finite element (FE) method, the proposed solution method is verified to provide an accurate and efficient way to calculate the dynamic characteristics of both intact and cracked cylindrical shells.

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