$-------------------------------------------------------------------------------
$                       RIGID FORMAT No. 1, Static Analysis
$     Shallow Spherical Shell Subjected to External Pressure Loading (1-7-1)
$ 
$ A. Description
$ 
$ The shallow spherical shell problem (see Problem 1-2-1) is again solved to
$ demonstrate the applicability of the shell cap generalization of the toroidal
$ ring element to this type of problem.
$ 
$ B. Input
$ 
$ The shallow spherical shell with a built-in edge is subjected to an external
$ pressure loading of 1 psi. Due to symmetry, only one half of the shell was
$ analyzed.
$  
$ 1. Parameters
$ 
$      r = 90.0 in.           (radius)
$ 
$      t = 3.0 in.            (thickness)
$                   6      2
$      E = 3.0  x 10  lb/in   (modulus of elasticity)
$ 
$      v = .1666              (Poisson's ratio)
$ 
$ 2. Constraints
$ 
$      u  =  0.0              all Grids
$       2
$ 
$      u   = u   = 0.0        Grid 1
$       1     4
$ 
$      u   = u   = u   = 0.0  Grid 14
$       1     3     4
$ 
$ 3. Loads
$ 
$ Forces and moments are applied to the grid points to simulate an external
$ pressure load of 1 psi.
$ 
$ C. Results
$ 
$ The meridional bending moment is taken to characterize the behavior predicted
$ for this structure. The exact solution from Reference 4 and the 13-element
$ NASTRAN model solution are quite close.
$ 
$ APPLICABLE REFERENCES
$ 
$ 4. S. Timoshemko, THEORY OF PLATES AND SHELLS. McGraw Hill, 1940.
$-------------------------------------------------------------------------------
