Nonlinear Transient Parameters dialog box

Name	Defines the name of the modeling object.
Label	Specifies a unique numerical identifier for the modeling object.
General
Number of Time Steps	NDT field in the TSTEPNL bulk data entry.Defines the number of time steps.
Time Increment	DT field in the TSTEPNL bulk data entry.Controls the initial value for the time step.
Interval for Output	NO field in the TSTEPNL bulk data entry.Lets you specify the time step interval at which the software generates output
Maximum Iterations per Time Step	MAXITER field in the TSTEPNL bulk data entry.Limits the maximum number of iterations in each time step.
Stiffness Updates
Converged Bisection Solutions	KSTEP field in the TSTEPNL bulk data entry.Specifies the number of converged bisection solutions between stiffness updates.
Convergence Criteria
Displacement	CONV field in the TSTEPNL bulk data entry.Lets you specify displacement (U) as a criterion for convergence.
Error Tolerance for Displacement	EPSU field in the TSTEPNL bulk data entry.If you select Displacement, specify the displacement (U) error tolerance.
Load	CONV field in the TSTEPNL bulk data entry.Lets you specify load (P) as a criterion for convergence.
Error Tolerance for Load	EPSP field in the TSTEPNL bulk data entry.If you select Load, specify the load (P) error tolerance.
Work	CONV field in the TSTEPNL bulk data entry.Lets you specify work (W) as a criterion for convergence.
Error Tolerance for Work	EPSW field in the TSTEPNL bulk data entry.If you select Work, specify the work (W) error tolerance.
Advanced
Maximum Diverging Conditions	MAXDIV field in the TSTEPNL bulk data entry.Limits the number of probable divergence conditions per iteration before the software assumes that the solution diverges.
Maximum Quasi-Newton Vectors	MAXQN field in the TSTEPNL bulk data entry.Lets you specify the maximum number of quasi-Newton correction vectors to save in the database.
Maximum Line Searches per Iteration	MAXLS field in the TSTEPNL bulk data entry.Controls the maximum number of line searches allowed for each iteration.
Effective Stress Fraction Limit	FSTRESS field in the TSTEPNL bulk data entry.Defines the fraction of effective stress used to limit the subincrement size in material routines.
Maximum Bisections	MAXBIS field in the TSTEPNL bulk data entry.Lets you define the maximum number of bisections allowed for each load increment.
Time Step Skip Factor	ADJUST field in the TSTEPNL bulk data entry.Controls the automatic time step adjustment.
Time Steps for Dominant Period Response	MSTEP field in the TSTEPNL bulk data entry.Specifies the number of steps to obtain the dominant period response. For nearly linear problems, the recommended value is 20.For highly nonlinear problems, a larger value, such as 40, is recommended.
Bounds for Adaptive Process	RB field in the TSTEPNL bulk data entry.Lets you define the bounds for maintaining the same time step for the stepping function during the adaptive process.
Maximum Adjusted versus Initial Ratio	MAXR field in the TSTEPNL bulk data entry.Lets you define the maximum ratio for the adjusted arc-length increment relative to the initial value.
Tolerance on Displacement Increment	UTOL field in the TSTEPNL bulk data entry.Specifies a tolerance on the displacement below which the software makes a special provision for numerical stability. This value is a tolerance that the software uses to filter undesirable time step adjustments.
Maximum Incremental Rotation	RTOLB field in the TSTEPNL bulk data entry.Lets you define the maximum value of incremental rotation allowed per iteration to activate bisection.
Structural Damping Includes Differential Stiffness	KDAMP field in the TSTEPNL bulk data entry.Indicates whether to include differential stiffness in the calculation of structural damping.Select Yes to include differential stiffness in the damping calculation.Select No to exclude differential stiffness from the damping calculation.
Stiffness Update Method	KTOL field in the TSTEPNL bulk data entry.Lets you specify the method for controlling stiffness updates.Select Automatic to have Simcenter Nastran select the most efficient update strategy based on convergence rates. At each step, the number of iterations required to converge is estimated. Stiffness is updated, if (i) the estimated number of iterations to converge exceeds the Maximum Iterations per Time Step, (ii) the estimated time required for convergence with current stiffness exceeds the estimated time required for convergence with updated stiffness, and (iii) the solution diverges.Select Full to have Simcenter Nastran update the stiffness matrix at every Newton-Raphson iteration. You should select Full for large deflection problems.

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Nonlinear Transient Parameters dialog box, Simcenter 3D 2021.1 Series

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