NLADAPTIVE, Component
, Action
, Criterion
, Option
, VAL1
, VAL2
, VAL3
Defines the criteria under which the mesh is refined or
modified during a nonlinear solution.
Component
Specifies the element component upon which this command should act:
ALL | — | All selected components, or all selected elements if no component is selected (default). |
| — | Component name. |
Action
Action to perform on the selected component(s):
ADD | — | Add a criterion to the database. |
LIST | — | List the criteria defined for the specified component(s). |
DELETE | — | Delete the criteria defined for the specified component(s). |
ON | — | Enable the defined criteria for the specified component(s) and specify how frequently
and when to check them (via
ON,,,
|
OFF | — | Disable the defined criteria for the specified component(s). |
Criterion
Type of criterion to apply to the selected component(s):
CONTACT | — | Contact-based. (Valid only for |
ENERGY | — | Energy-based. (Valid only for |
BOX | — | A position-based criterion, defined by a box. (Valid only for
|
MESH | — | A mesh-quality-based criterion. (Valid only for |
ALL | — | All criteria and options. (Valid only for |
Option
Criterion option to apply to the selected component(s):
NUMELEM | — | For target elements only, defines the minimum number of contact elements to contact
with each target element. If this criterion is not satisfied, the program refines the
contact elements and the associated solid elements. For this option,
|
MEAN | — | Checks the strain energy of any element that is part of the defined component for the
condition Ee ≥ c1 *
Etotal / |
XYZRANGE | — | Defines the location box in which all elements within are to be split or refined. Up
to six values following the |
SKEWNESS | — | Mesh-quality control threshold for element SOLID285. Valid
values ( |
SHAPE | — | Mesh-quality control threshold for element PLANE182. (Valid
only for
|
WEAR | — | For contact elements having surface wear specified (TB,WEAR) only,
defines |
ALL | — | All options. (Valid only for |
If a specified component (Component
) is an assembly, the defined criterion applies to all element components
included in the assembly.
All components must be defined and selected before the first solve (SOLVE), although their nonlinear adaptivity criteria can be modified from load step to load step, and upon restart. For nonlinear adaptivity to work properly, ensure that all components are selected before each solve.
After using this command to define a new criterion, the new
criterion becomes active and is checked one time during each load
step, roughly in mid-loading (unless this behavior is changed via Action
= ON).
When a criterion is defined, it overwrites a previously defined criterion (if one exists) through the same component, or through the component assembly that includes the specified component.
During solution, the same criteria defined for an element through
different components are combined, and the tightest criteria and action
control (Action
,ON,,,VAL1
) are used. If an ON action is defined by a positive VAL1
value through one component and a negative VAL1
value through another, the program uses the positive
value.
For Action
= ON, if VAL2
(start time) and/or VAL3
(end time) are unspecified or invalid, the program uses the start
and/or end time (respectively) of the load step. If VAL1
< 0, the program checks VAL1
points
between VAL2
and VAL3
. The time interval between each check points is determined by (VAL3
- VAL2
) / (VAL1
+ 1), with the first check point as close to VAL2
+ (VAL3
- VAL2
) / (VAL1
+ 1) as possible.
Fewer check points can be used if the number of substeps during solution
is insufficient (as the program can only check at the end of a substep).
Option
= SKEWNESS
applies to linear tetrahedral element SOLID285 only. When the skewness of a SOLID285 element
is >= the defined value, the element is used as the core (seed) element
of the remeshed region(s). If this criterion is used together with
any other criteria for the same component, the other criteria defined
for the component are ignored. The most desirable skewness value is
0, applicable when the element is a standard tetrahedral element;
the highest value is 1, applicable when the element becomes flat with
zero volume. For more information about skewness and remeshing, see Mesh Nonlinear Adaptivity in the Advanced Analysis Guide.
For more granular control of the source mesh geometry, see NLMESH.