Workshop 1
Array Parameters
Axisymmetric Wheel
1. Array Parameters
Axisymmetric Wheel
Workshop Supplement
• Given: A database file containing an axisymmetric model
with material properties defined.
INTRODUCTION TO ANSYS 6.0 - Part 2
• Determine the standard deviation of the von Mises stress
distribution in a steel wheel spinning at 7500 rpm.
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1. Array Parameters
Axisymmetric Wheel
Workshop Supplement
Enter ANSYS in the working directory specified by your instructor using “axiwheel”
as the jobname.
2.
Resume the “axiwheel.db1” database file.
3.
Constrain the bottom line in UY direction.
–
Main Menu > Soluion > -Loads- Apply > Displacement > On Lines
–
Or issue:
/SOLU
DL,1,,UY
INTRODUCTION TO ANSYS 6.0 - Part 2
1.
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1. Array Parameters
Axisymmetric Wheel
Apply a 7500-rpm angular velocity about the Y-axis. Since ANSYS requires
radians/second units, we will use APDL to convert 7500 rpm to rad/sec.
–
Type in the Input window (or in the Scalar Parameters dialog):
rpm=7500
pi=3.142
w=2*pi*rpm/60
–
Main Menu > Solution > -Loads- Apply > Other > Angular Velocity …
–
• OMEGY = w, then [OK]
Or issue:
OMEGA,,W
5.
Save the database and solve.
INTRODUCTION TO ANSYS 6.0 - Part 2
4.
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1. Array Parameters
Axisymmetric Wheel
Plot von Mises stress contours in POST1 (general postprocessor).
7.
If desired, expand the axisymmetric solution to 270°.
–
Utility Menu > PlotCtrls > Style > Symmetry Expansion > 2-D Axisymmetric …
•
Expansion amount = 3/4 expansion
•
[OK]
–
Utility Menu > PlotCtrls > Pan,Zoom,Rotate…
–
• [ISO]
Or issue:
/EXPAND,27,AXIS,,,10
/VIEW,1,1,1,1
/REPLOT
INTRODUCTION TO ANSYS 6.0 - Part 2
6.
Workshop Supplement
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1. Array Parameters
Axisymmetric Wheel
We will use the element table and array parameters to calculate the standard
deviation of von Mises stresses. First load equivalent stresses into the element table:
–
Main Menu > General Postproc > Element Table > Define Table …
•
[Add…]
– Lab = eseqv
– Item, Comp = Stress, von Mises SEQV
– [OK]
–
• [Close]
Or issue:
ETABLE,ESEQV,S,EQV
INTRODUCTION TO ANSYS 6.0 - Part 2
8.
Workshop Supplement
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1. Array Parameters
Axisymmetric Wheel
Plot and list the element table values.
–
–
–
–
–
Utility Menu > PlotCtrls > Style > Symmetry Expansion > No Expansion
Main Menu > General Postproc > Element Table > Plot Elem Table …
• Itlab = ESEQV
• Avglab = Yes - average
• [OK]
Utility Menu > PlotCtrls > Pan,ZOOM,Rotate…
• [Front]
Main Menu > General Postproc > Element Table > List Elem Table …
• Lab1-9 = ESEQV
• [OK]
Or issue:
/EXPAND
PLETAB,ESEQV,1
/VIEW,1,1,1,1
/REPLOT
PRETAB
INTRODUCTION TO ANSYS 6.0 - Part 2
9.
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1. Array Parameters
Axisymmetric Wheel
Workshop Supplement
–
–
Utility Menu > Parameters > Get Scalar Data …
•
Type of data = Model data, For selected set; then [OK]
•
Name of parameter = nelem
•
Data to be retrieved = Current elem set, Number of elem's
•
[OK]
Utility Menu > Parameters > Array Parameters > Define/Edit …
•
[Add…]
– Par = sarray
– Type = Array
– I, J, K = nelem, 1, 1
– [OK]
–
• [Close]
Or issue:
*GET,NELEM,ELEM,,COUNT
*DIM,SARRAY,,NELEM
INTRODUCTION TO ANSYS 6.0 - Part 2
10. We now need to "upload" the element table values into an array parameter. First
dimension an array with number of rows = number of elements:
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1. Array Parameters
Axisymmetric Wheel
–
–
Utility Menu > Parameters > Get Array Data …
•
Type of data = Results data, Elem table data; then [OK]
•
Name of array parameter = sarray(1)
•
Elem table item to be retrieved = ESEQV
•
Fill array by looping on = Element number
• [OK]
Or issue:
*VGET,SARRAY(1),ELEM,1,ETAB,ESEQV
12. Verify the values in the array parameter.
–
Utility Menu > List > Status > Parameters > Named Parameter …
•
–
Par = SARRAY
• [OK]
Or issue:
*STAT,SARRAY
INTRODUCTION TO ANSYS 6.0 - Part 2
11. Fill the array with von Mises stress values from the element table.
Workshop Supplement
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1. Array Parameters
Axisymmetric Wheel
Workshop Supplement
–
–
Utility Menu > Parameters > Array Operations > Vector-Scalar Func …
•
ParR = sdev
•
Par1 = sarray(1)
•
Func = Std deviatn STDV
•
[OK]
Utility Menu > Parameters > Scalar Parameters …
•
–
Check the value of SDEV
• [Close]
Or issue:
*VSCFUN,SDEV,STDV,SARRAY(1)
*STAT,SDEV
14. If time permits, rerun the solution with the addition of a UX=0 constraint on the inner
face of the wheel, calculate the standard deviation, and compare with the previous
value.
15. Exit ANSYS.
INTRODUCTION TO ANSYS 6.0 - Part 2
13. Calculate the standard deviation.
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