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 Arc-length control. Surface to surface formulation is
used for no-penetration contacts when you select the
Arc length Control method.
|
|
Iterative |
Sets the numerical technique to be
used for iterations.
Newton-Raphson (NR)
|
Use the Newton-Raphson (NR) iterations.
|
Modified Newton-Raphson (MNR)
|
Use the Modified Newton-Raphson (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 surface-to-surface 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 X-direction |
UY: Y
Translation |
displacement
in the Global Y-direction |
UZ: Z
Translation |
displacement
in the Global Z-direction |
RX: X Rotation |
rotation
about the Global X-direction for shell studies
only |
RY: Y Rotation |
rotation
about the Global Y-direction for shell studies
only |
RZ: Z Rotation |
rotation
about the Global Z-direction 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 surface-to-surface contact formulation is supported when activating the
Displacement Control.
Arc-Length completion options
Maximum
load pattern multiplier |
The maximum load-pattern
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 user-defined 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 (0-1) |
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.