The Advanced tab in the Nonlinear dialog box sets options for controlling the
solution method. This tab appears when clicking Advanced
Options from the Solution
tab.
Method
Sets the control technique and the iterative method to be used.
Control 
Choose a control technique. Only
Force control is
available for dynamic studies.
Force

Use force control.

Displacement

Use Displacement control.

Arc length

Use Arclength control. Surface to surface formulation is
used for nopenetration contacts when you select the
Arc length Control method.


Iterative 
Sets the numerical technique to be
used for iterations.
NewtonRaphson (NR)

Use the NewtonRaphson (NR) iterations.

Modified NewtonRaphson (MNR)

Use the Modified NewtonRaphson (MNR)
iteration scheme.


Integration 
Sets the integration
method. 
Displacement control options
You can use the Displacement Control method to solve nonlinear
contact analysis with the Direct Sparse and Intel Direst Sparse solvers only. The
Displacement control method can handle post buckling behavior in nonlinear analysis.
Only the surfacetosurface contact formulation is supported when activating the
Displacement Control.
Select
a vertex or reference point to control the
analysis 
Select a vertex or a reference
point to drive the solution. If you select a reference point, the
program uses the closest node to the specified point. 
Displacement component for the selected
location 
Displacement component. Sets the
displacement component to be used in the displacement control
method. The valid components are:
UX: X
Translation 
displacement
in the Global Xdirection 
UY: Y
Translation 
displacement
in the Global Ydirection 
UZ: Z
Translation 
displacement
in the Global Zdirection 
RX: X Rotation 
rotation
about the Global Xdirection for shell studies
only 
RY: Y Rotation 
rotation
about the Global Ydirection for shell studies
only 
RZ: Z Rotation 
rotation
about the Global Zdirection for shell studies
only 

Displacement variation with time 
Click Edit to define a time variation of the displacement
using the Time Curve dialog
box. After defining the time variation of the selected displacement
component, click Graph to
view the displacement as a function of time. 
You can use the Displacement Control method to solve nonlinear
contact analysis with the Direct Sparse and Intel Direst Sparse solvers only. The
Displacement control method can handle post buckling behavior in nonlinear analysis.
Only the surfacetosurface contact formulation is supported when activating the
Displacement Control.
ArcLength completion options
Maximum
load pattern multiplier 
The maximum loadpattern
multiplier at which the solution is to be terminated (approximate
value). Default is 1.0E8. 
Maximum
displacement (for translational DOF) 
The analysis terminates if any
displacement DOF exceeds this value. 
Maximum
number of arc steps 
The analysis terminates if the
number of arc length steps reaches this limit. Default is 50.

Initial
arc length multiplier 
To start the arc length solution, an initial arc length is
calculated by a userdefined arc length multiplier multiplied by
a representative displacement. Default is 1.0.

Intermediate Results
Show
intermediate results up to current iteration 
Select to visualize intermediate result plots while
running a nonlinear study. When the first iteration step completes,
the results for the active plot are shown on the graphics area. As
the solution progresses to the next iteration step, the active plot
gets dynamically updated. If you have not selected a result plot,
the first default plot under the Results folder is dynamically updated in the
graphics area. By getting visual feedback of
the results as the solution progresses, you can make decisions
to either stop the simulation and make adjustments to the
nonlinear study settings, or let the solution proceed with the
current settings.

Step/Tolerance options
Sets convergence and equilibrium parameters.
Do
equilibrium iteration every 
Sets the frequency of performing
equilibrium in number of solution steps. 
Maximum
equilibrium iterations 
Sets the maximum number of
equilibrium iterations for any solution step. 
Convergence tolerance 
Relative displacement tolerance
used for equilibrium convergence. 
Maximum
increment strain 
Sets tolerance for strain
increment for models with creep or plasticity. 
Singularity elimination factor (01) 
Sets stiffness singularity elimination factor (normal
solution is set to 1; if less than 1.0, the program modifies
stiffness terms causing singularity to help convergence.) If normal
solution fails, trying a different value, for example 0, may help
convergence. 
Neither the Arc Length nor the Displacement Control method can
resolve rigid body motions that can occur during a nonlinear solution. If you
encounter a rigid body motion during a nonlinear analysis, use the Force Control
method with a Prescribed displacement to improve chances of reaching
convergence.