Create an Analysis Step with a Text Editor

Define a step with the proper time incrementation and nonlinear solution controls that best allow Simulation Composite Analysis to reach a converged solution.

We have already defined our model geometry and are now ready to create a load step. Many linear elastic analyses require only a single increment per step. However, a single increment is inadequate for simulations of progressive failure.

1. Open a bulk data file with a text editor and locate the SUBCASE entry.
2. Below the SUBCASE entry, add the following line:

      NLSTEP = 1

3. Now locate the BEGIN BULK entry. Below this, add the following lines:

   NLSTEP, 1, 1.0
    , GENERAL, 1000
    , FIXED, 100,
    , MECH, PV, , 0.005

Together, these 5 lines define a nonlinear step to use for the analysis. The NLSTEP we have defined uses 100 increments over a total time of 1.0. We have also requested that 1000 equilibrium iterations be performed before the code evaluates the need to reduce the time incrementation. This allows MSC Nastran to take advantage of the improved convergence characteristics provided by Simulation Composite Analysis. We also used the NLSTEP entry to modify the default force convergence tolerance.

For additional details on the NLSTEP entry as it pertains to Simulation Composite Analysis, refer to the User's Guide.

The bulk data file should now appear similar to what is shown below:

SUBCASE 1
   NLSTEP = 1
   SPC = 2
   LOAD = 1
$
BEGIN BULK
$
NLSTEP, 1, 1.0
 , GENERAL, 1000
 , FIXED, 100,
 , MECH, PV, , 0.005
$

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