pred

Mapdl.pred(sskey='', lskey='', **kwargs)

Activates a predictor in a nonlinear analysis.

APDL Command: PRED

Parameters:

sskey

Substep predictor key:

OFF - No prediction occurs.

ON - Use a predictor on all substeps after the first.

AUTO - The program uses a predictor but, within certain

exceptions, automatically switches prediction off. This behavior is the default; see “Command Default” for details.

lskey

Load step predictor:

OFF - No prediction across load steps occurs. This is the

default behavior.

ON - Use a predictor also on the first substep of the load

step. (Sskey = ON is required.)

Notes

Activates a predictor in a nonlinear analysis on the degree-of-freedom solution for the first equilibrium iteration of each substep.

When using the arc-length method (ARCLEN, ARCTRM), you cannot issue the DOF solution predictor command (PRED), the automatic time stepping command (AUTOTS), or the line search command (LNSRCH). If you activate the arc-length method after you set PRED, AUTOTS, or LNSRCH, a warning message appears. If you elect to proceed with the arc-length method, the program disables your DOF predictor, automatic time stepping, and line search settings, and the time step size is controlled by the arc- length method internally.

When using step-applied loads, such as TUNIF, BFUNIF, etc., or other types of non-monotonic loads, the predictor may adversely affect the convergence. If the solution is discontinuous, the predictor may need to be turned off.

When performing a nonlinear analysis involving large rotations, the predictor may require using smaller substeps.

This command is also valid in PREP7.