NLHIST
NLHIST, Key, Name, Item, Comp, NODE, ELEM, SHELL, LAYER
Specify result items to track during solution.
MP ME ST PR PRN <> <> <> <> <> <> PP <> EME MFS
Key

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.

Name

The 32-character user-specified name.

Item, Comp

Predetermined output item and component label for valid elements. See the Element Reference for more information.

NODE

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.

ELEM

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.

SHELL

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

Layer number (for layered elements only). Used only for element nodal data (ESOL).

Notes

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 nlhist140 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).

Table: NLHIST - Valid NSOL Item and Component Labels

ItemCompDescription
UX, Y, ZX, Y, or Z structural displacement.
ROTX, Y, ZX, Y, or Z structural rotation.
FX, Y, ZX, Y, or Z structural reaction force.
MX, Y, ZX, Y, or Z structural reaction moment.
TEMP [1]-Temperature.
TEMPMAX, MINMaximum or minimum temperature in the model.
HEAT [2]-Reaction heat flow.
  1. For SHELL131 and SHELL132 elements with KEYOPT(3) = 0 or 1, use the labels TBOT, TE2, TE3, . . ., TTOP instead of TEMP.

  2. For SHELL131 and SHELL132 elements with KEYOPT(3) = 0 or 1, use the labels HBOT, HE2, HE3, . . ., HTOP instead of HEAT.

Table: NLHIST - Valid ESOL Item and Component Labels

ItemCompDescription
SX, Y, Z, XY, YZ, XZComponent stress.
"1, 2, 3Principal stress.
"INTStress intensity.
"EQVEquivalent stress.
EPELX, Y, Z, XY, YZ, XZComponent elastic strain.
"1, 2, 3Principal elastic strain.
"INTElastic strain intensity.
"EQVElastic equivalent strain.
EPPLX, Y, Z, XY, YZ, XZComponent plastic strain.
"1, 2, 3Principal plastic strain.
"INTPlastic strain intensity.
"EQVPlastic equivalent strain.
EPCRX, Y, Z, XY, YZ, XZComponent creep strain.
"1, 2, 3Principal creep strain.
"INTCreep strain intensity.
"EQVCreep equivalent strain.
EPTHX, Y, Z, XY, YZ, XZComponent thermal strain.
"1, 2, 3Principal thermal strain.
"INTThermal strain intensity.
"EQVThermal equivalent strain.
NLSEPLEquivalent stress (from stress-strain curve).
"SRATStress state ratio.
"HPRESHydrostatic pressure.
"EPEQAccumulated equivalent plastic strain.
"CREQAccumulated equivalent creep strain.
"PSVPlastic state variable.
"PLWKPlastic work/volume.
TGX, Y, Z, SUMComponent thermal gradient or vector sum.
TFX, Y, Z, SUMComponent 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.

Table: NLHIST - Valid PAIR Item and Component Labels

ItemCompDescription
CONTELCNIf >0, number of contact elements in contact. Other values are interpreted as follows:
0 indicates the contact pair is in near-field contact status.
-1 indicates the contact pair is in far-field contact status.
-2 indicates that the contact pair is inactive (symmetric to asymmetric contact).
"ELSTNumber of contact elements in sticking contact status.
"CNOSMaximum chattering level.
"PENEMaximum penetration (or minimum gap). [1]
"CLGPMaximum closed (geometrical) gap.
"SLIDMaximum total sliding distance.
"ESLIMaximum elastic slip distance.
"KNMXMaximum normal contact stiffness.
"KTMXMaximum tangential contact stiffness.
"KNMNMinimum normal contact stiffness.
"KTMNMinimum tangential contact stiffness.
"PINBMaximum pinball radius.
"PRESMaximum contact pressure.
"SFRIMaximum frictional stress.
"CNDPAverage contact depth.
"CLPEMaximum closed (geometrical) penetration.
"LGPENumber of contact points having too much penetration.
"CAREAContacting area.
"NDMPMaximum contact damping pressure.
"TDMPMaximum tangential contact damping stress.
  1. For PENE, a positive value indicates a penetration, and a negative value indicates a gap. If the contact pair has a far-field contact status, penetration and gap are not available, and the value stored for PENE is the current pinball radius.

Menu Paths

Main Menu>Solution>Results Tracking

Release 14.0 - © 2011 SAS IP, Inc. All rights reserved.