workshop 01.2: postprocessing

1 © 2017 ANSYS, Inc. October 13, 2017

Release 18.2

Workshop 01.2: PostprocessingIntroduction to ANSYS LS-DYNA


•Goal: To become familiar with the various files that LS-DYNA writes and the alternate postprocessing tools they provide

Workshop 01.2: Postprocessing


Result Files and Post Processing in WB LS-DYNA• LS-DYNA result files− ASCII (time history)

− Binary (d3plot; interface force file)

• Output Controls

• Program messages in d3hsp and messag

• Postprocessing in WB LS-DYNA− Available results in WB

− Worksheet

− ASCII files

− Contact results


Result files

• LS-DYNA writes several result database files

• Important are− Binary result files

• Binary plot file d3plot

• Interface force file input.intfor

− ASCII result files

• Different files for time history post processing

• binout (ASCII files in binary format)

d3plot

ASCII result


Result files

Output Controls

• Analysis Settings/Output Controls for d3plot output control− Strain=Yes for output of strain tensor (default is No)

− Equally spaced points for number of output states

• Hint: It’s possible to overwrite output controls with a keyword snippet or with an input file include


Result files

Output Controls

• Analysis Settings/Time History Output Controls for ASCII output control− Most often used files are written by default • GLSTAT

• MATSUM

• BNDOUT

• RCFORC

• SPCFORC

• NODOUT / ELOUT

− Equally spaced points for number of output states (1000 is default)

• Under Time History Output Controls additional files can be selected


Result files

d3plot file

• d3plot is a fixed name for the binary result file

• Contains:− model with nodes and elements− nodal and element results:• displacement, velocity, acceleration• strain, stress

• Used for contour result display and result animation

• Because of file size, about 20 to 100 states are requested

• d3plot is split into a family of d3plotnn files − First file is named d3plot − Following files are sequentially numbered (d3plot01, d3plot02, …)− For LSPP, d3plot is read and all other files are automatically appended

• WB automatically reads d3plot files into Mechanical after solving− Manual d3plot import is available from the LS-DYNA Post toolbar


Result files

Interface force file

• Result file for contact results only

• Predefined file name in WB LS-DYNA: input.intfor

• There is no default file name if LS-DYNA isn’t started from Mechanical− Interface force file is written only if requested on the execution line s=input.intfor− Interface force file can’t be requested if MAPDL Product Launcher is used

• Family of input.intfornn files − In LSPP, input.intfor has to be selected

• Results are stored for contact segments only− For contacts, results are stored for each contact and target (slave and master) side

• Results are contact normal and tangential pressure, contact forces, …− For some contacts also gap− No penetration results, no contact status results

• Default output interval is the same as for d3plot


Result files

ASCII files

• Result database for time history results

• Typically, about 1000+ states are written− But depends on model and required results

• ASCII files have predefined names like glstat, matsum, …


Result files for History Output

These files are written by default in WB LS-DYNA. Other files have to be requested (see Output Controls). Nodout and elout require additional definition (node and element selection). They allow output of results with higher frequency than d3plot.

ASCII file name WB descriptor Content

GLSTAT Global Data Global Status - Model energy balance, time step, mass scal.

MATSUM Material Energies Data Material Summary – part energy balance

RCFORC Resultant Interface Force Data Resultant Contact Forces – forces for contact and target side

SPCFORC SPC reaction Forces Data Single Point Constraint Forces – fixed support reaction forc.

BNDOUT Boundary Condition Forces and Energy

Boundary output – prescribed displ./velocity reaction force

NODOUT Nodal Data Node Output – Nodal displ./veloc./accel.

ELOUT Element Data Element Output – element results (stress, strain, beam force)


Result files for History Output

ASCII file name WB descriptor Content

RBDOUT Rigid Body Data Rigid Body Data Output – displ., veloc, accel. of rigid bodiesRecommended if moving rigid bodies existing

SLEOUT Sliding Interface Energy Sliding Energy Output – contact energy and frictional energyRecommended for contact debugging

GCEOUT Geometry contact Enities Contact forces from geometric contact entities

SWFORC Nodal Constraint Reaction Force Data

Spotweld forces (only if spotwelds are defined)

NCFORC Nodal Interface Forces Contact forces for all nodes (can become very large!)

RWFORC Wall Forces Rigid Wall Force, only if rigidwalls are defined

DEFORC Discrete Element Data Discrete Element Forces, only for discrete springs/dampers

JNTFORC Joint Forces Data Joint Forces, only if joints are defined

These files are not written by default in WB LS-DYNA. If needed, they have to be requested (see Output Controls).Especially SLEOUT can be very helpful in case of contact trouble.


Result files

binout

• LS-DYNA MPP version writes binout files instead of ASCII files

• Only glstat is written as ASCII for MPP runs

• Binout is a binary database and summarizes different ASCII output in one combined format

• There are two ways to post process binout− Binout is converted to regular ASCII files. This requires use of the program l2a

− LSPP can read binout files and then can be processed like ASCII files

• Best practice is to use a batch file to start LS-DYNA; after completion of the run l2a.exe may convert binout to ASCII

• Depending on the data size of all ASCII files, a certain number of binoutnnnn files can be written. File d3hsp contains a list of binoutnnnn files


Result files

Time History Tracker

• nodout requires node selection LS-DYNA Pre/Time History/Result Tracker

• Element selection for elout is not supported, requires command snippet


Result files

Time History Tracker

• rcforc reports contact forces (target/contact (master/slave) contacts )

• rcforc doesn’t include the force of Body InteractionsIf contact forces acting on bodies of a Body Interaction are required, a Body Contact Tracker has to be used (insert from LS-DYNA Pre/Time History) − Insert before solve

− Body selection only


Output files

d3hsp

• d3hsp echoes the LS-DYNA keyword input

• Summary of all settings and definitions

• Summary of mass

• 100 smallest time steps

• Summary of time including elapsed time, number of CPUs used

• Header contains LS-DYNA version information

messag

• Similar to the messages sent to standard output

• Warnings and errors– Check after each run for warnings

– Errors cause LS-DYNA to stop. Check for “Normal termination”

• For SMP there is only one file messag

• For MPP there are files mesnnnn for each cpu, error messages and warnings can be located in such a local mesnnnn file.


Postprocessing in WB LS-DYNA

• Major differences between advertised options and actually supported options can be found in Solution

• This is related to different result file structure and available results

• Some results require post processing in LSPP

• Available results also depend on Output Controls in Analysis Settings


Postprocessing in Mechanical

• Supported results− Deformation (displacement, velocity, acceleration)

− Stress

− Probes: displacement, velocity, acceleration

− User Defined Results via Worksheet

• Not supported− Elastic strain (toolbar and worksheet)

− Damage

− Tools

− Coordinate Systems

− Snippets

− Probes other than displacement, velocity, acceleration



• The Worksheet offers more results than actually available, i.e. the following results are not supported− Elastic strain tensor (EPEL)

− Plastic strain tensor (EPPL)

• TEMP is the “nodal percentage mass increase”, not temperature

• EPS is the equiv. log. plastic strain (plastic strain in LSPP)



Time History from LS-DYNA ASCII files

• Results can be inserted from the Solution Information toolbar

• Some results like “Time Increment” and “Energy Summary” are already predefined under Solution Information

• For noisy results, like accelerations or forces, a Butterworth filter can be applied.



Contact results

• WB LS-DYNA exports contact results into input.intforonly for contacts, not for Body Interactions− Body Interactions don’t support keyword snippets

• Supported results− Normal pressure

− Shear stress

− Nodal force (vector plot)


Summary

• There are many different result files produced during the LS-DYNA run− d3plot for contour results

− ASCII for time history

• Make sure to output the desired results, i.e. think about ASCII files and Time History tracker

• The Worksheet allows access to additional user defined results

• Pay attention, not all options are actually supported

• LSPP extends the WB LS-DYNA capability and offers full featured post processing

workshop 01.2: postprocessing

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