PLSLIMIT 

 — 

Maximum equivalent plastic strain allowed within a time-step (substep). If the calculated value exceeds VALUE, the program performs a cutback (bisection). Default: VALUE = 0.15 (15 percent)

If CUTCONTROL with Lab = PLSLIMIT is not issued, the minimum time step specified is reached, and the maximum plastic limit calculated from the solution exceeds 15 percent, the program generates a warning and continues the Newton iterations.

If CUTCONTROL with Lab = PLSLIMIT is issued, the minimum time step specified is reached, and the maximum plastic limit calculated exceeds the specified limit, the program generates an error and stops the Newton iterations.

CRPLIMIT 

 — 

Set values for calculating the maximum equivalent creep ratio allowed within a time step. If the calculated maximum creep ratio exceeds the defined creep ratio limit, the program performs a cutback.

VSLIMIT 

 — 

For viscoelastic materials, the maximum equivalent viscous strain increment allowed within a time step. If the calculated value exceeds VALUE, the program performs a cutback (bisection). If VALUE is unspecified, the program does not check the equivalent viscous strain increment.

DPPLMT 

 — 

Set the maximum pore-pressure increment allowed within a time step. If the calculated maximum increment exceeds the specified limit, the program performs a cutback. This option has no default and is valid for coupled structural-pore-fluid-diffusion Analysis analysis only.

DSPLIMIT 

 — 

Maximum incremental displacement within the solution field in a time step (substep). If the maximum calculated value exceeds VALUE, the program performs a cutback (bisection). Default: VALUE = 1.0 x 10⁷

NPOINT 

 — 

Number of points in a cycle for a second order dynamic equation, used to control automatic time stepping. If the number of solution points per cycle is less than VALUE, the program performs a cutback in time step size. Default: VALUE = 13 (linear analysis) or 5 (nonlinear analysis). A larger number of points yields a more accurate solution but also increases the solution run time.

This option works well for linear problems. For nonlinear analyses, other factors such as contact status changes and solution convergence rate can overwrite NPOINT. (See Automatic Time Stepping in the Mechanical APDL Theory Reference for more information about automatic time stepping.)

NOITERPREDICT 

 — 

If VALUE = 0 (default), the program predicts the number of iterations for nonlinear convergence and performs a cutback earlier than the number of iterations specified via the NEQIT command. This is the recommended option.

If VALUE = 1, the solution iterates (if nonconvergent) to NEQIT number of iterations before a cutback is invoked. It is sometimes useful for poorly-convergent problems, but rarely needed in general.

Bisection is also controlled by contact status change, plasticity or creep strain limit, and other factors. If any of these factors occur, bisection still occurs, regardless of the NOITERPREDICT setting.

CUTBACKFACTOR 

 — 

Changes the cutback value for bisection. Default = 0.5, where 0 < VALUE < 1. This option is active only when AUTOTS,ON.

IMPRATIO 

 — 

Set the maximum creep ratio value for implicit creep. Default = 0.0 (no creep limit control). Any positive value is valid.

EXPRATIO  

 — 

Set the maximum creep ratio value for explicit creep. Default = 0.1. Any positive value up to 0.25 is valid.

STSLIMIT  

 — 

Stress threshold for calculating the creep ratio. For integration points with effective stress below this threshold, the creep ratio does not cause cutback. Default = 0.0. Any positive value is valid.

STNLIMIT  

 — 

Elastic strain threshold for calculating the creep ratio. For integration points with effective elastic strain below this threshold, the creep ratio does not cause cutback. Default = 0.0. Any positive value is valid.