Orthotropic Shallow Spherical Shell on a Kerr Foundation

1997 ◽  
Vol 119 (1) ◽  
pp. 131-133
Author(s):  
D. N. Paliwal ◽  
H. Kanagasabapathy ◽  
K. M. Gupta
Keyword(s):  
Spherical Shell ◽  
Shear Layer ◽  
Parametric Study ◽  
Shallow Spherical Shell ◽  
Static Behavior ◽  
Nonlinear Static ◽  
Foundation Parameters ◽  
Shell Geometry

Parametric study involving foundation parameters and shell geometry is carried out for nonlinear static behavior of an orthotropic shallow spherical shell on a Kerr foundation. Study shows that the deflection reduces if the shell curvature or the foundation parameters of the shear layer and the lower spring layer are increased. Shells with immovable edges are found to be more prone and vulnerable to changes in various parameters than those with movable edges.

Vibrations of a Shallow Spherical Shell on a Kerr Foundation

1994 ◽  
Vol 116 (1) ◽  
pp. 47-52 ◽  
Author(s):  
D. N. Paliwal ◽  
R. Srivastava
Keyword(s):  
Spherical Shell ◽  
Elastic Foundation ◽  
Elastic Properties ◽  
Parametric Study ◽  
Large Amplitude ◽  
Free Vibrations ◽  
Shallow Spherical Shell ◽  
Foundation Model ◽  
Foundation Parameters ◽  
Clamped Edges

Large amplitude free vibrations of a clamped shallow spherical shell on a Kerr-type elastic foundation model are investigated. A detailed parametric study is conducted involving geometric and elastic properties of the shell as well as representative foundation parameters. Influence of these variables on the relation between the nondimensional frequency and amplitude are discussed. Shells with immovably clamped edges are more vulnerable to the changes in the above-referred parameters than those with movable clamped edges.

Large Amplitude Free Vibration of Shallow Spherical Shell on a Pasternak Foundation

1993 ◽  
Vol 115 (1) ◽  
pp. 70-74 ◽  
Author(s):  
D. N. Paliwal ◽  
V. Bhalla
Keyword(s):  
Free Vibration ◽  
Spherical Shell ◽  
Large Amplitude ◽  
Free Vibrations ◽  
Numerical Results ◽  
Shallow Spherical Shell ◽  
Pasternak Foundation ◽  
New Approach ◽  
Foundation Parameters ◽  
Clamped Edges

Large amplitude free vibrations of a clamped shallow spherical shell on a Pasternak foundation are studied using a new approach by Banerjee, Datta, and Sinharay. Numerical results are obtained for movable as well as immovable clamped edges. The effects of geometric, material, and foundation parameters on relation between nondimensional frequency and amplitude have been investigated and plotted.

The Onset of Plastic Yielding in a Spherical Shell Compressed by a Rigid Flat

2010 ◽  
Vol 78 (1) ◽  
Author(s):  
Longqiu Li ◽  
Izhak Etsion ◽  
Andrey Ovcharenko ◽  
Frank E. Talke
Keyword(s):  
Spherical Shell ◽  
Normal Load ◽  
Empirical Relation ◽  
Solid Sphere ◽  
Plastic Yielding ◽  
Element Analysis ◽  
Shell Parameter ◽  
Shell Geometry ◽  
Limiting Value ◽  
Critical Contact

The onset of plastic yielding in a spherical shell loaded by a rigid flat is analyzed using finite element analysis. The effect of spherical shell geometry and material properties on the critical normal load, critical interference, and critical contact area, at the onset of plastic yielding, is investigated and the location where plastic yielding first occurs is determined. A universal dimensionless shell parameter, which controls the behavior of the spherical shell, is identified. An empirical relation is found for the load-interference behavior of the spherical shell prior to its plastic yielding. A limiting value of the dimensionless shell parameter is identified above which the shell behaves like a solid sphere.

Zero Gravity Validation of Smart Aperture Antennas

1999 ◽  
Author(s):  
Hwan-Sik Yoon ◽  
Gregory Washington
Keyword(s):  
Spherical Shell ◽  
Analytical Model ◽  
Stress Function ◽  
Spherical Shape ◽  
Element Model ◽  
Shallow Spherical Shell ◽  
Zero Gravity ◽  
Governing Equations ◽  
Homogeneous Solutions ◽  
Calculated Stress

Abstract In this study, a smart aperture antenna of spherical shape is modeled and experimentally verified. The antenna is modeled as a shallow spherical shell with a small hole at the apex for mounting. Starting from five governing equations of the shallow spherical shell, two governing equations are derived in terms of a stress function and the axial deflection using Reissner’s approach. As actuators, four PZT strip actuators are attached along the meridians separated by 90 degrees respectively. The forces developed by the actuators are considered as distributed pressure loads on the shell surface instead of being applied as boundary conditions like previous studies. This new way of applying the actuation force necessitates solving for the particular solutions in addition to the homogeneous solutions for the governing equations. The amount of deflections is evaluated from the calculated stress function and the axial deflection. In addition to the analytical model, a finite element model is developed to verify the analytical model on the various surface positions of the reflector. Finally, an actual working model of the reflector is built and tested in a zero gravity environment, and the results of the theoretical model are verified by comparing them to the experimental data.

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