a post 26 primer - phoenix analysis & design technologies ... · pdf filea post 26 primer: ......

DX R13: 02/17/2011
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A Post 26 Primer: Post Processing over Multiple
Time/Load Steps in Mechanical APDL
Eric Miller
Co-Owner
Principal, Simulation and
Business Technologies
04/12/2012
PADT, Inc.

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Agenda
Note: This presentation is being
recorded
Introductions
Fundamentals
Defining Variables
Viewing Variables
Calculating
Other POST26 Tools
Suggestions and
Recommendations

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Introductions

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Upcoming Webinars Upcoming Webinars
Feb 9, 2012 - 12:00 MST
Working Directly with Nodes and Elements in ANSYS Mechanical
Feb 23, 2012 - 12:00 MST
Assembly Meshing in ANSYS R14 CANCELED
March 8, 2012 - 12:00 MST
Intro to Workbench Framework Scripting - Controlling projects, materials, and solution execution with python
March 22, 2012 - 12:00 MST
Mastering the Remote Solver Manager (RSM) at R14
April 12, 2012 12:00 MST
A POST26 Primer: Post Processing over Multiple Time/Load Steps in Mechanical APDL
April 26, 2012 12:00 MST
A Constraint Equation Primer: How to Tie Degrees of Freedom Together
May 10, 2012 12:00 MST
Optimization with ANSYS DesignXplorer at R14
May 24, 2012 12:00 MST
Modeling Moisture Diffusion in ANSYS
Summer Break: June & July (maybe August)
Primers are new:
Oriented towards newer users or Workbench users who may not have experience with
some of the fundamentals in the ANSYS Mechanical APDL solver
See upcoming and past webinars at:
padtincevents.webex.com
Click on ANSYS Webinar Series

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About PADT
PADT is an Engineering Services
Company
Mechanical Engineering
18 Years of Growth and Happy customers
70ish Employees
3 Business Areas
CAE Sales & Services
Consulting, Training, Sales, Support
Product Development
Rapid Prototyping & Manufacturing
Learn More: www.PADTINC.com
We Make Innovation Work

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Cube HVPC Systems
Balance between speed and cost
Mini-Cluster
96 Cores / 512 GB RAM / 6 TB Disk
Mobile Rack / UPS / Monitor / Keyboard
$34,900
Compute Server
$14,250
Simulation Workstation (Intel)
$11,750
Simulation Workstation (AMD)
$6,300
www.CUBE-HVPC.com

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PeDAL The APDL Editor Side-by-side editor and help viewer layout.
Instant help on any documented APDL command by pressing F1.
Full syntax highlighting for ANSYS v12 Mechanical APDL.
Auto-complete drop downs for APDL Commands.
APDL Command argument hints while typing commands.
Search ANSYS help phrases and keywords.
Multiple tabs for the editor and html viewer.
Full capability web browser built in allows for rich web experience and web
searches.

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Connect with PADT
Facebook:
facebook.com/padtinc
Twitter:
#padtinc
LinkedIn:
Search on PADT, Inc.
Email Subscriptions: www.padtinc.com/epubs
Web:
www.PADTINC.com
ANSYS User Blog:
padtinc.com/focus

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Fundamentals

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Assumptions
You know the basics of MAPDL
You are not an MAPDL expert or guru
Need reminders on where some of the commands are
That you will be accessing this via the MAPDL GUI, APDL
macros, and code snippets in Workbench

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ANSYS Results The ANSYS RST file stores results at various points
A point can be at a given time in a transient run or it can
be a location on a load curve for a static run
Not necessarily every point that a solution is calculated at
User determines how often results are saved
Each record has a time, load step, and sub step
associated with it
Static or Transient, even modal results are stored the
same way
Header and analysis type tell you what type of solution you
have
Do a SET,LIST to see what is in the file
Results are stored by node or element
DOF stuff by node
Stresses/Strains/etc by element at each corner node
So to get at Stress/Strains/etc you must
Average over an element
Un-averaged for a corner node
Average over all elements attached to a node

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Conventions/Words We will refer to a given loadstep/substep, time point, or frequency as a
point
Solution set is the collection of result solutions stored in the RST file. It is
made up of solution points.
The database is not the *.db file.
It is the model and result information currently stored in memory
An array is an APDL parameter of type array
A vector you can stick stuff in

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POST1 vs. POST26 POST1, the general post processor
It looks at results across the whole model at a given point
LS/SS, Time, or Freq
Use it to make contour plots, animations, list results at a given point
SET,LS,SS,FACT,KIMG,TIME to store a given point in the database
POST26, the Time History Post Processor
Looks at a result value on a node or element over the solution set
Instead of loading all the results at a point into the database, it stores
the results over the solution set for user specified nodes or elements
No model plots, just lists and graphs (usually vs. time)
Allows complex calculations on results
You can do what POST26 does
in POST1 with do loops
But every step loads all results slow
POST26 skips through the file - fast
set,1,1
dim,myux,,nmstp
*do,i,1,nmstp
*get,myux(i),node,mynode,u,x
set,next
*enddo

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Getting into POST26
/post26
Required, commands are filtered
Click on TimeHist PostPro in Main Menu

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Its all About Variables
A table of a result item at a location in the model vs time or
frequency
Not an APDL parameter
But you can push one into an array
You tell POST26 what variables you want to create
Whole set of commands for defining, modifying,
mathamatizing, and controlling variables
Also a GUI tool to build the commands

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Our Test Model
Infamous Tower of Test
Transient, large deflection
Move base in UX (time,ux):
0,0
.1,1
.2,5
.3,0
1,0
Will post on blog
finish
/clear
/prep7
blc4,-1,-1,2,2,60
et,1,185
mptemp,1,70
mpdata,ex,1,1,20e6
mpdata,nuxy,1,1,.23
mpdata,dens,1,1,.001
alphad,5
esize,.9
vmesh,all
/view,1,1,1,1
/vup,1,z
eplot
nsel,s,loc,z,0
cm,nbt,node
nsel,all
d,nbt,uy,0
d,nbt,uz,0
d,nbt,ux,1
time,.1
antype,4
trnopt,full
lumpm,0
nlgeom,1
kbc,0
timint,1
nsubst,40,40,40
outres,all,1
lswrite,1
d,nbt,ux,5
time,.2
lswrite,2
d,nbt,ux,0
time,.3
lswrite,3
time,2
lswrite,4
/solu
lssolve ,1,4
finish
/post1
plnsol,u,sum
/POST26
FILE,'p26','rst','.'
/UI,COLL,1
NUMVAR,200
SOLU,191,NCMIT
STORE,MERGE
FILLDATA,191,,,,1,1
REALVAR,191,191
!*
NSOL,2,18,U,X, UX_2
STORE,MERGE
XVAR,1
PLVAR,2

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Defining Variables

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Defining Variables
You have to tell POST26 what information you want and how
you want it:
Node/Element, Where in an element, What type of result, How to
average, etc
Each variable has a unique variable number
You access the variable with this number for operations/plotting/etc
You can also give it a name: Label only
Use:
ANSOL, NSOL, ESOL, EDREAD, RFORCE, JSOL, GSSOL, GAPF,
SOLU
Control with:
FORCE, LAYERP26, SHELL, CFACT, TVAR
Or use the Tool
NOTE: Time or Freq automatically created and is Var=1

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Two Step Process
Define the variables with variable definition commands
Store them in the database
Separate Store for efficiency
Reads all the variables in at once

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Time History Variable Tool
When you enter POST26 in the GUI, it comes up
Or click TimeHist Postpro->Variable Viewer
Even if you are doing scripting, use the GUI to figure it out

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Defining Variables in the Tool
Click the Plus Sign
Pick from list
It handles all the op

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