Nonlinear Parameters dialog box

Name	Defines the name of the modeling object.
Label	Specifies a unique numerical identifier for the modeling object.
General
Number of Increments	NINC field in the NLPARM bulk data entry.Specifies the number of increments to process in the subcase.
Time Increment for Creep	DT field in the NLPARM bulk data entry.Specifies the incremental time interval for creep analysis.
Maximum Iterations per Load Increment	MAXITER field in the NLPARM bulk data entry.Controls the maximum number of iterations for each load increment.
Intermediate Output Flag	INTOUT field in the NLPARM bulk data entry.Controls the output requests for displacements, element forces, stresses, etc.
Stiffness Updates
Method	KMETHOD field in the NLPARM bulk data entry.Lets you specify the method for controlling stiffness updates.To have Nastran automatically select the most efficient strategy based on convergence rates, select AUTO.To have Nastran perform a single iteration for each load increment, update the stiffness matrix,and then select the most efficient strategy based on convergence rates, select SEMI.To have the software update the stiffness matrix after the number of iterations you specify, select ITER.
Iterations Before Update	KSTEP field in the NLPARM bulk data entry.If you select ITER from the Method list, lets you specify the number of iterations before the stiffness update occurs.
Convergence Criteria
Displacement	U option for the CONV field in the NLPARM bulk data entry.Lets you specify displacement (U) as a criterion for convergence.
Error Tolerance for Displacement	EPSU field in the NLPARM bulk data entry.If you select Displacement, specify the displacement (U) error tolerance.
Load	P option for the CONV field in the NLPARM bulk data entry.Lets you specify load (P) as a criterion for convergence.
Error Tolerance for Load	EPSP field in the NLPARM bulk data entry.If you select Load, specify the load (P) error tolerance.
Work	W option for the CONV field in the NLPARM bulk data entry.Lets you specify work (W) as a criterion for convergence.
Error Tolerance for Work	EPSW field in the NLPARM bulk data entry.If you select Work, specify the work (W) error tolerance.
Advanced
Maximum Diverging Conditions	MAXDIV field in the NLPARM bulk data entry.Lets you specify the limit on probable divergence conditions per iteration before the software assumes that the solution diverges.
Maximum Quasi-Newton Vectors	MAXQN field in the NLPARM 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 NLPARM bulk data entry.Controls the maximum number of line searches allowed for each iteration.
Effective Stress Fraction Limit	FSTRESS field in the NLPARM bulk data entry.Lets you define the fraction of effective stress used to limit the subincrement size in material routines.
Line Search Tolerance	LSTOL field in the NLPARM bulk data entry.Lets you define the line search tolerance.
Maximum Bisections	MAXBIS field in the NLPARM bulk data entry.Lets you define the maximum number of bisections allowed for each load increment.
Maximum Adjusted versus Initial Ratio	MAXR field in the NLPARM bulk data entry.Lets you define the maximum ratio for the adjusted arc-length increment relative to the initial value.
Maximum Incremental Rotation	RTOLB field in the NLPARM bulk data entry.Lets you define the maximum value of incremental rotation allowed per iteration to activate bisection.

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Controlling the iteration strategy in Nastran nonlinear analyses

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Nonlinear Parameters dialog box, Simcenter 3D 2021.1 Series

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