Determination of the natural frequencies and mode configurations for small vibrations of an orthotropic cylindrical shell with attached masses

1981 ◽  
Vol 17 (2) ◽  
pp. 138-142 ◽  
Author(s):  
S. V. Kozlov
Keyword(s):  
Cylindrical Shell ◽  
Natural Frequencies ◽  
Orthotropic Cylindrical Shell

Numerical Determination of Natural Frequencies and Modes of the Vibrations of a Thick-Walled Cylindrical Shell

2018 ◽  
Vol 54 (1) ◽  
pp. 75-84 ◽  
Author(s):  
A. Ya. Grigorenko ◽  
M. Yu. Borisenko ◽  
E. V. Boichuk ◽  
A. P. Prigoda
Keyword(s):  
Cylindrical Shell ◽  
Natural Frequencies ◽  
Numerical Determination ◽  
Natural Frequencies And Modes

Vibration of Thin Cylindrical Shells

1965 ◽  
Vol 7 (4) ◽  
pp. 399-407 ◽  
Author(s):  
G. B. Warburton
Keyword(s):  
Cylindrical Shell ◽  
General Solution ◽  
Mode Shape ◽  
Shell Length ◽  
Natural Frequencies ◽  
Equations Of Motion ◽  
Frequency Factor ◽  
Thin Cylindrical Shell ◽  
End Conditions

Starting from Flügge's three equations of motion for a uniform thin cylindrical shell, the paper gives a general solution, from which the dependence of natural frequencies on shell dimensions and mode number can be investigated for any end conditions. This solution requires the assumption of a natural frequency and the determination of the corresponding shell length for the prescribed end conditions. Numerical results are given for shells with clamped ends and for shells with free ends; the variation of frequency factor and of mode shape with dimensional and mode parameters is shown and the accuracy of approximate theories assessed.

scholarly journals Determination of rotating cylindrical shell natural frequencies

2012 ◽  
Author(s):  
А.А. Герасименко ◽  
◽  
А.М. Гуськов ◽  
М.А. Гуськов ◽  
Ф. Лоронг ◽  
...  
Keyword(s):  
Cylindrical Shell ◽  
Natural Frequencies ◽  
Rotating Cylindrical Shell

Experimental Determination of SEA Parameters of Stiffened Cylindrical Shell Structure

2006 ◽  
Vol 3-4 ◽  
pp. 315-324
Author(s):  
P. Ramachandran ◽  
S. Narayanan
Keyword(s):  
Cylindrical Shell ◽  
Natural Frequencies ◽  
Prediction Method ◽  
Radiation Efficiency ◽  
Laser Vibrometer ◽  
Correction Procedure ◽  
Discrete Elements ◽  
Stiffened Cylindrical Shell ◽  
Modal Density

A method to predict the modal density and radiation efficiency of orthogonally stiffened cylindrical shell is presented in this paper. The modal density is derived using energy method from the undamped natural frequencies of stiffened shell by treating the stiffeners as discrete elements. The band averaged radiation efficiency is estimated by categorizing the structural modes into acoustically fast and acoustically slow modes. The predicted parameters are compared with experimental results using laser vibrometer measurements. Phase-roll off has been observed in laser vibrometer measurements for which a correction procedure is applied. This prediction method can be easily extended to shells with stiffeners having different size, orientation etc.

Collapse of Arteries Subjected to an External Band of Pressure

1980 ◽  
Vol 102 (1) ◽  
pp. 8-22 ◽  
Author(s):  
A. M. Hecht ◽  
H. Yeh ◽  
S. M. K. Chung
Keyword(s):  
Reynolds Number ◽  
Blood Flow ◽  
Cylindrical Shell ◽  
Orthotropic Cylindrical Shell ◽  
Reynolds Numbers ◽  
Intraluminal Pressure ◽  
Collapse Pressure ◽  
Vessel Size ◽  
Flow Reynolds Number ◽  
Small Band

Collapse of arteries subjected to a band of hydrostatic pressure of finite length is analyzed. The vessel is treated as a long, thin, linearly elastic, orthotropic cylindrical shell, homogeneous in composition, and with negligible radial stresses. Blood in the vessel is treated as a Newtonian fluid and the Reynolds number is of order 1. Results are obtained for effects of the following factors on arterial collapse: intraluminal pressure, length of the pressure band, elastic properties of the vessel, initial stress both longitudinally and circumferentially, blood flow Reynolds number, compressibility, and wall thickness to radius ratio. It is found that the predominant parameter influencing vessel collapse for the intermediate range of vessel size and blood flow Reynolds numbers studied is the preconstricted intraluminal pressure. For pressure bands less than about 10 vessel radii the collapse pressure increases sharply with increasing intraluminal pressure. Initial axial prestress is found to be highly stabilizing for small band lengths. The effects of fluid flow are found to be small for pressure bands of less than 100 vessel radii. No dramatic orthotropic vessel behavior is apparent. The analysis shows that any reduction in intraluminal pressure, such as that produced by an upstream obstruction, will significantly lower the required collapse pressure. Medical implications of this analysis to Legg-Perthes disease are discussed.

Studies on Determination of Natural Frequencies of Industrial Turbine Blades

1995 ◽  
Author(s):  
Mahesh M. Bhat ◽  
V. Ramamurti ◽  
C. Sujatha
Keyword(s):  
Steam Turbine ◽  
Dynamic Behavior ◽  
Turbine Blade ◽  
Natural Frequencies ◽  
Complex Structure ◽  
Turbine Blades ◽  
Blade Root ◽  
Steam Turbine Blade ◽  
Manufacturing Tolerances

Abstract Steam turbine blade is a very complex structure. It has geometric complexities like variation of twist, taper, width and thickness along its length. Most of the time these variations are not uniform. Apart from these geometric complexities, the blades are coupled by means of lacing wire, lacing rod or shroud. Blades are attached to a flexible disc which contributes to the dynamic behavior of the blade. Root fixity also plays an important role in this behavior. There is a considerable variation in the frequencies of blades of newly assembled turbine and frequencies after some hours of running. Again because of manufacturing tolerances there can be some variation in the blade to blade frequencies. Determination of natural frequencies of the blade is therefore a very critical job. Problems associated with typical industrial turbine bladed discs of a 235 MW steam turbine are highlighted in this paper.

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