Release 11.0 Documentation for ANSYS
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NLHIST, Key, Name, Item, Comp, NODE, ELEM, SHELL, LAYER
Specify result items to track during solution.
MP ME ST PR PRN <> <> <> <> <> <> PP <>
Specifies the command operation:
NSOL | — | Nodal solution data. |
ESOL | — | Element nodal data. |
PAIR | — | Contact data (pair-based). |
STAT | — | Displays a list of items to track. |
OFF, or 0 | — | Deactivates tracking of all variables. This value is the default. |
ON, or 1 | — | Activates tracking of all variables. Tracking also activates whenever any specification changes. |
DEL | — | Removes the specified variable from the set of result items to track. If Name = ALL (default), all specifications are removed. |
The 32-character user-specified name.
Predetermined output item and component label for valid elements. See the Elements Reference for more information.
Valid node number (if Key = NSOL or ESOL), or valid real constant set number (if Key = PAIR) identifying a contact pair. Required input for NSOL, ESOL, and PAIR items.
Valid element number for element results. Used for ESOL items. If ELEM is specified, then a node number that belongs to the element must also be specified in the NODE field.
Valid labels are TOP, MID or BOT. This field can specify the location on shell elements for which to retrieve data. Used only for element nodal data (ESOL).
Layer number (for layered elements only). Used only for element nodal data (ESOL).
The NLHIST command is a nonlinear diagnostics tool allowing you to monitor diagnostics results of interest in real time during solution.
You can track a maximum of 50 variables during solution. The specified result quantities are written to the file Jobname.nlh. Nodal results and contact results are written for every converged substep (irrespective of the OUTRES command setting) while element results are written only at time points specified via the OUTRES command. For time points where element results data is not available, a very small number is written instead. If the conditions for contact to be established are not satisfied, 0.0 will be written for contact results.
Results tracking is available only for a nonlinear structural analysis (static or transient), a nonlinear steady-state thermal analysis, or a transient thermal analysis (linear or nonlinear). All results are tracked in the Solution Coordinate System (that is, nodal results are in the nodal coordinate system and element results are in the element coordinate system). Results tracking is not available for FLOTRAN analyses.
The Jobname.nlh file is an ASCII file that lists each time point at which a converged solution occurs along with the values of the relevant result quantities.
The GUI option Solution> Results tracking provides an interface to define the result items to be tracked. The GUI also allows you to graph one or more variables against time or against other variables during solution. You can use the interface to graph or list variables from any .nlh file generated by the ANSYS program.
You can also track results during batch runs. Either access the ANSYS Launcher and select File Tracking from the Tools menu, or type nlhist110 at the command line. Use the supplied file browser to navigate to your Jobname.nlh file, and click on it to invoke the tracking utilty. You can use this utilty to read the file at any time, even after the solution is complete (the data in the file must be formatted correctly).
Specifications that you set via the NLHIST command are not saved in the database (.db file).
NLHIST - Valid NSOL Item and Component Labels
| Item | Comp | Description |
|---|---|---|
| U | X, Y, Z | X, Y, or Z structural displacement. |
| ROT | X, Y, Z | X, Y, or Z structural rotation. |
| F | X, Y, Z | X, Y, or Z structural reaction force. |
| M | X, Y, Z | X, Y, or Z structural reaction moment. |
| TEMP [1] | - | Temperature. |
| TEMP | MAX, MIN | Maximum or minimum temperature in the model. |
| HEAT [2] | - | Reaction heat flow. |
NLHIST - Valid ESOL Item and Component Labels
| Item | Comp | Description |
|---|---|---|
| S | X, Y, Z, XY, YZ, XZ | Component stress. |
| " | 1, 2, 3 | Principal stress. |
| " | INT | Stress intensity. |
| " | EQV | Equivalent stress. |
| EPEL | X, Y, Z, XY, YZ, XZ | Component elastic strain. |
| " | 1, 2, 3 | Principal elastic strain. |
| " | INT | Elastic strain intensity. |
| " | EQV | Elastic equivalent strain. |
| EPPL | X, Y, Z, XY, YZ, XZ | Component plastic strain. |
| " | 1, 2, 3 | Principal plastic strain. |
| " | INT | Plastic strain intensity. |
| " | EQV | Plastic equivalent strain. |
| EPCR | X, Y, Z, XY, YZ, XZ | Component creep strain. |
| " | 1, 2, 3 | Principal creep strain. |
| " | INT | Creep strain intensity. |
| " | EQV | Creep equivalent strain. |
| EPTH | X, Y, Z, XY, YZ, XZ | Component thermal strain. |
| " | 1, 2, 3 | Principal thermal strain. |
| " | INT | Thermal strain intensity. |
| " | EQV | Thermal equivalent strain. |
| NL | SEPL | Equivalent stress (from stress-strain curve). |
| " | SRAT | Stress state ratio. |
| " | HPRES | Hydrostatic pressure. |
| " | EPEQ | Accumulated equivalent plastic strain. |
| " | CREQ | Accumulated equivalent creep strain. |
| " | PSV | Plastic state variable. |
| " | PLWK | Plastic work/volume. |
| TG | X, Y, Z, SUM | Component thermal gradient or vector sum. |
| TF | X, Y, Z, SUM | Component thermal flux or vector sum. |
ETABLE items are not supported for ESOL items.
PAIR solution quantities are output on a "per contact pair" basis. As a consequence, the corresponding values listed in the Jobname.nlh file represent a minimum or a maximum over the associated contact pair, as detailed in the table below.
NLHIST - Valid PAIR Item and Component Labels
| Item | Comp | Description | |||
|---|---|---|---|---|---|
| CONT | ELCN | If >0, number of
contact elements in contact. Other values are interpreted as follows:
| |||
| " | ELST | Number of contact elements in sticking contact status. | |||
| " | CNOS | Maximum chattering level. | |||
| " | PENE | Maximum penetration (or minimum gap). [1] | |||
| " | CLGP | Maximum closed (geometrical) gap. | |||
| " | SLID | Maximum total sliding distance. | |||
| " | ESLI | Maximum elastic slip distance. | |||
| " | KNMX | Maximum normal contact stiffness. | |||
| " | KTMX | Maximum tangential contact stiffness. | |||
| " | KNMN | Minimum normal contact stiffness. | |||
| " | KTMN | Minimum tangential contact stiffness. | |||
| " | PINB | Maximum pinball radius. | |||
| " | PRES | Maximum contact pressure. | |||
| " | SFRI | Maximum frictional stress. | |||
| " | CNDP | Average contact depth. | |||
| " | CLPE | Maximum closed (geometrical) penetration. | |||
| " | LGPE | Number of contact points having too much penetration. |
Distributed ANSYS supports only the tracking of pair-based contact data (NLHIST,PAIR) and the applicable supporting options (STAT / ON / OFF / DEL).