Set the solution controls to improve the solution.
The default solution controls in ANSYS typically do not allow for a robust and efficient solution in a progressive failure simulation of a composite structure. Specific solution control parameters used in conjunction with Helius PFA allow for a solution with a decreased tendency for time increment cutbacks. This results in a faster overall solution time. These solution controls are defined in the following steps. For further information regarding each command, refer to the ANSYS documentation and the Helius PFA User's Guide.
Enter the following commands into the command prompt:
TIME, 1 - Specifies a step size equal to 1.
NSUBST, 20, 20, 20 - This command specifies the number of substeps to be used in the analysis. Since the step time is 1, each substep time in the increment will be 0.05.
NEQIT, 1000 - This command specifies the number of equilibrium iterations that must be performed before ANSYS evaluates the need to reduce the time incrementation size. It is intentionally large to force ANSYS to converge at each of the specified time steps.
NROPT, FULL, , OFF - This command instructs ANSYS to use the 'Full' Newton Raphson algorithm and prevents ANSYS from using the 'Adaptive Descent' algorithm.
PRED, OFF, , OFF - This command prevents ANSYS from using the converged solution at the last substep to estimate the solution for the current substep.