scholarly journals Functionally gradient isotropic cylindrical shell locally heated by heat sources

2019 ◽  
Vol 6 (2) ◽  
pp. 367-373
Author(s):  
Musii Musii ◽  
◽  
U. V. Zhydyk ◽  
O. Ya. Mokryk ◽  
N. B. Melnyk ◽  
...  
Keyword(s):  
Cylindrical Shell ◽  
Heat Sources ◽  
Functionally Gradient ◽  
Isotropic Cylindrical Shell

Damping of isotropic cylindrical shell vibrations

1977 ◽  
Vol 13 (9) ◽  
pp. 945-946 ◽  
Author(s):  
A. A. Bondarenko ◽  
A. I. Telalov
Keyword(s):  
Cylindrical Shell ◽  
Isotropic Cylindrical Shell

Hydromagnetic convective instability of a rotating, self-gravitating fluid sphere containing a uniform distribution of heat sources

1977 ◽  
Vol 353 (1673) ◽  
pp. 145-162 ◽  
Keyword(s):  
Cylindrical Shell ◽  
Uniform Distribution ◽  
Critical Rayleigh Number ◽  
Plane Layer ◽  
Fluid Sphere ◽  
Dynamo Model ◽  
Planar Geometry ◽  
Heat Sources ◽  
Curvature Effects ◽  
The Waves

The desire to understand better the magneto-hydrodynamics of the Earth's and planetary interiors has recently motivated a number of studies on convective motions in hydromagnetic rotating systems. These studies have, however, been restricted to planar geometry, the convective layer being confined between two horizontal planes in externally applied uniform gravitational and magnetic fields. This paper takes a step further to the geophysical and astrophysical contexts by restoring curvature effects. The linear stability of a uniformly rotating, self-gravitating fluid sphere in the presence of a co-rotating zonal magnetic field is studied when buoyancy is provided by a uniform distribution of heat sources. The analysis is limited to the case where the Chandrasekhar number, Q , and the Taylor number, λ 2 , are both large. (These are, respectively, dimension-less measures of Lorentz and Coriolis forces relative to the viscous forces.) It is shown that for all values of λ and Q the motions appearing at marginal convection are necessarily time-dependent and associated with a temperature fluctuation which is always symmetric with respect to the equatorial plane. The critical Rayleigh number R c ( λ, Q ), which is a dimensionless measure of the temperature contrast necessary for the onset of convection, is found to be qualitatively the same as for the planar model only when λ ≥ O(Q) , although even in this case certain characteristic curvature effects arise. The motions prevalent at marginal stability, when O ( Q 3/2 ) ≥ λ ≫ Q , occur in the form of a thin cylindrical shell of thickness O (( Q/λ ) 2/3 ) and whose distance from the axis of rotation varies between 0.4 and 0.6 spherical radii depending on the value of q , which is the ratio of the thermal to the magnetic diffusivities. The waves will drift westward or eastward according to whether q ≶ 2.5. (The cause of disagreement in this result with Busse (1975 b ) is explained in an appendix). For λ = O(Q) convection occurs in the whole volume of the sphere and the waves drift westward for all values of q . When λ ≪ Q , not only is R c incorrectly given by that for the plane layer model but also modal degeneracies of convection in the plane layer are removed by the curvature and boundedness of the system. For this range of λ and Q convection again fills the whole sphere but all forms of diffusion are concentrated in multiple boundary layers on the surface of sphere. The waves drift westward. The results are compared with parellel studies, including Braginsky's MAC waves (i. e. Hide's slow magnetohydrodynamic waves) and Busse's recent dynamo model. In particular, it is argued that the last of these may not be representative of planetary magnetism because of a convective growth of field (not considered by Busse) associated with convection patterns occuring in the whole sphere rather than in a cylindrical shell.

Buckling of Stiffened Curved Panels and Cylindrical Shells: A Study of Comparison Among Various Theories

2012 ◽  
Author(s):  
S. Harutyunyan ◽  
D. J. Hasanyan ◽  
R. B. Davis
Keyword(s):  
Cylindrical Shell ◽  
Circular Cylindrical Shell ◽  
Cylindrical Shells ◽  
Laminated Composite ◽  
Physical Parameters ◽  
Buckling Loads ◽  
Isotropic Cylindrical Shell ◽  
Analytical Formulas ◽  
Laminated Composite Shells ◽  
Curved Panels

Formulation is derived for buckling of the circular cylindrical shell with multiple orthotropic layers and eccentric stiffeners acting under axial compression, lateral pressure, and/or combinations thereof, based on Sanders-Koiter theory. Buckling loads of circular cylindrical laminated composite shells are obtained using Sanders-Koiter, Love, and Donnell shell theories. These theories are compared for the variations in the stiffened cylindrical shells. To further demonstrate the shell theories for buckling load, the following particular case has been discussed: Cross-Ply with N odd (symmetric) laminated orthotropic layers. For certain cases the analytical buckling loads formula is derived for the stiffened isotropic cylindrical shell, when the ratio of the principal lamina stiffness is F = E2/E1 = 1. Due to the variations in geometrical and physical parameters in theory, meaningful general results are complicated to present. Accordingly, specific numerical examples are given to illustrate application of the proposed theory and derived analytical formulas for the buckling loads. The results derived herein are then compared to similar published work.

VIBRO-ACOUSTIC RESPONSE OF A CIRCULAR ISOTROPIC CYLINDRICAL SHELL UNDER A THERMAL ENVIRONMENT

2011 ◽  
Vol 03 (03) ◽  
pp. 525-541 ◽  
Author(s):  
P. JEYARAJ ◽  
C. PADMANABHAN ◽  
N. GANESAN
Keyword(s):  
Cylindrical Shell ◽  
Thermal Environment ◽  
Power Level ◽  
Mode Shapes ◽  
Sound Power ◽  
Sudden Increase ◽  
Acoustic Response ◽  
Response Characteristics ◽  
Sound Power Level ◽  
Isotropic Cylindrical Shell

This paper presents numerical simulation studies on the vibration and acoustic response-characteristics of an isotropic cylindrical shell under a thermal environment using commercial softwares ANSYS and SYSNOISE. First, the critical buckling temperature is obtained, followed by modal and harmonic response analyses considering pre-stress due to the thermal field in the cylindrical shell, with the critical buckling temperature as a parameter. The vibration response predicted is then used to compute the sound radiation. It is found that there is a significant change in the vibration mode shapes and ring frequency towards the lowest natural frequency with an increase in temperature. There is a sudden increase in overall sound power level near the critical buckling temperature and significant changes in mode shapes with temperature does not affect the overall sound power level.

Asymptotic Evaluation of a Combined Stress-Intensity Factor for a Pressurized Cylindrical Shell Containing a Longitudinal Crack

1980 ◽  
Vol 47 (3) ◽  
pp. 583-585 ◽  
Author(s):  
J. W. Nicholson ◽  
M. R. Bradley ◽  
C. K. Carrington
Keyword(s):  
Stress Intensity Factor ◽  
Cylindrical Shell ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Asymptotic Form ◽  
Longitudinal Crack ◽  
Asymptotic Formulas ◽  
Combined Stress ◽  
Isotropic Cylindrical Shell ◽  
Asymptotic Evaluation

Sanders’ path-independent energy-release-rate integral I for a cracked shallow shell is used to compute the asymptotic form of the combined stress-intensity factor for a pressurized elastically isotropic cylindrical shell containing a longitudinal crack. The combined stress-intensity factor is expressible in terms of the conventional stretching and bending stress-intensity factors and is a function of Poisson’s ratio v and a dimensionless crack length λ. When λ is small the shell is nearly flat and when λ is large the shell is very thin. Asymptotic formulas for I when λ is small or large are obtained. A numerical solution for λ = 0(1) is also obtained.

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