$-------------------------------------------------------------------------------
$                       RIGID FORMAT No. 1, Static Analysis
$          Rectangular Plate With Variable Moduli of Elasticity (1-17-1)
$ 
$ A. Description
$ 
$ This problem illustrates the use of the element stress precision check
$ feature, NCHECK. A rectangular plate is modeled using CQUAD2 elements. The
$ thickness is constant, but the modulus of elasticity is varied versus distance
$ along the plate length. Concentrated forces and thermal loads are applied so
$ as to produce uniform stress distribution in selected directions. The problem
$ is designed so that stress calculations for certain elements will involve
$ operations with small differences between large numbers to produce a loss of
$ precision in the calculations.
$ 
$ B. Input
$ 
$ The relevant data are listed below.
$ 
$ 1. Parameters:
$ 
$    t = 1.0 inch              (Plate thickness)
$ 
$    E =                       (Modulus of elasticity)
$ 
$    v =  0.0                  (Poisson's ratio)
$                    -6
$    alpha = 1.0 x 10   in/in/deg. F (Thermal expansion coefficient)
$ 
$    T = 170 deg. F            (Applied temperature, uniform)
$ 
$    T  = 70 deg. F            (Reference temperature)
$     o
$ 
$ 2. Constraints:
$ 
$    Subcases 1, 2, and 3
$ 
$      u  =   0                    at all Grid points
$       6
$      u  = u  =  0                at Grids 11 and 13
$       2    3
$ 
$      u  = u  = u  = u  = u  = 0  at Grid 12
$       1    2    3    4    5
$ 
$    Subcase  4
$ 
$      u  =   0                    at all Grid points
$       6
$ 
$      u  = u  = u  = u  = u  = 0  at Grid points 11, 12, 13, 51, 52, and 53
$       1    2    3    4    5
$ 
$ 3. Loads:
$ 
$    Subcase I F  = 100. at Grids 51 and 53
$               y
$ 
$              F  = 400. at Grid 52
$               y
$ 
$    Subcase 2  F  = 1000. at Grid 52
$                x
$ 
$    Subcase 3  F  =  100. at Grid 52
$                z
$ 
$    Subcase 4  T  =  170. deg. F at all Grids
$ 
$ 4. Output Requests:
$ 
$    Displacements of all grid points
$ 
$    Stresses of all elements
$ 
$    Stress precision check to 12 significant figures
$ 
$ C. Results
$ 
$ A summary of stress precision in the number of significant digits is presented
$ in Table 1. The quantities shown in the table are indicative of the general
$ trends observed in all stress precision output for this problem. The trend
$ shows that elements with higher moduli of elasticity provide less precise
$ stresses relative to the other elements under the same loading.
$ 
$                         Table 1. Stress Precision Summary
$     -------------------------------------------------------------------------
$          Case        Modulus of  Subcase 1  Subcase 2   Subcase 3  Subcase 4
$         (CDC)        Elasticity
$     -------------------------------------------------------------------------
$       Significant                sigma        tau          M       sigma
$     Load or Stress                    y          xy         y           y
$     -------------------------------------------------------------------------
$                           3
$     Elements 11, 12     10        14.5        >12        >12        >12
$                           5
$     Elements 21, 22     10        12.1         11.4       11.9      >12
$                           7
$     Elements 31, 32     10        10.1          9.2        9.7       10.6
$                           9
$     Elements 41, 42     10         8.1          7.1        7.2        9.0
$     -------------------------------------------------------------------------
$ 
$ 
$     -------------------------------------------------------------------------
$          Case        Modulus of  Subcase 1  Subcase 2   Subcase 3  Subcase 4
$         (IBM)        Elasticity
$     -------------------------------------------------------------------------
$       Significant                sigma        tau          M       sigma
$     Load or Stress                    y          xy         y           y
$     -------------------------------------------------------------------------
$                           3
$     Elements 11, 12     10         7.2        >12        >12        >12
$                           5
$     Elements 21, 22     10         4.9          4.2        4.7      >12
$                           7
$     Elements 31, 32     10         2.9          2.0        2.5        3.3
$                           9
$     Elements 41, 42     10         1.0          0.5        1.7        2.0
$     -------------------------------------------------------------------------
$ 
$ 
$     -------------------------------------------------------------------------
$          Case        Modulus of  Subcase 1  Subcase 2   Subcase 3  Subcase 4
$       (UNIVAC)       Elasticity
$     -------------------------------------------------------------------------
$       Significant                sigma        tau          M       sigma
$     Load or Stress                    y          xy         y           y
$     -------------------------------------------------------------------------
$                           3
$     Elements 11, 12     10         8.1        >12        >12        >12
$                           5
$     Elements 21, 22     10         5.8          5.1        5.6      >12
$                           7
$     Elements 31, 32     10         3.8          2.9        3.4        4.3
$                           9
$     Elements 41, 42     10         1.0          0.8        0.7        2.7
$     -------------------------------------------------------------------------
$-------------------------------------------------------------------------------
