Transcript Large Deflection - Arched Beam

Workshop 7
Nonlinear Analysis
Large Deflection
Arched Beam
7. Nonlinear Analysis - Large Deflection
Arched Beam
Workshop Supplement
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A shallow arch is subjected to a 20,000N force at its midspan.
Determine the midspan displacement using both a linear and
nonlinear (large-deflection) analysis, then compare the results.
INTRODUCTION TO ANSYS 6.0 - Part 2
Description
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7. Nonlinear Analysis - Large Deflection
Arched Beam
INTRODUCTION TO ANSYS 6.0 - Part 2
Loads and Material Properties
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7. Nonlinear Analysis - Large Deflection
Arched Beam
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Enter ANSYS in the working directory specified by your instructor using “beamarch”
as the jobname.
2.
We recommend building the model using steps 3-12, but if you don't want to, you may
resume an existing database (beamarch.db1), then skip to step 13.
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Utility Menu > File > Resume from …
Or issue:
RESUME,beamarch,db1
3.
Define 4 keypoints in the global cylindrical system: kp1 at (1270,75), kp2 at (1270,90),
kp3 at (1270,105), kp4 at (1270sin45, 90). Kp4 is the orientation keypoint.
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Utility Menu > WorkPlane > Change Active CS to > Global Cylindrical
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Main Menu > Preprocessor > -Modeling- Create > Keypoints > In Active CS …
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Utility Menu > Parameters > Angular Units ...
Or issue:
/PREP7
CSYS,1
K,1,1270,75
K,2,1270,90
K,3,1270,105
*AFUN,DEG
K,4,(1270*SIN(45)),90
INTRODUCTION TO ANSYS 6.0 - Part 2
1.
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7. Nonlinear Analysis - Large Deflection
Arched Beam
Define lines (arcs) from keypoints 1 to 2 and keypoints 2 to 3:
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5.
Define the element type to be BEAM189, and then define material properties
(EX=210e3 MPa, PRXY=0.3):
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6.
Main Menu > Preprocessor > -Modeling- Create > -Lines- Lines > In Active Coord +
Or issue:
L,1,2
L,2,3
Main Menu > Preprocessor > Element Type > Add/Edit/Delete …
Main Menu > Preprocessor > Material Props > Material Models …Structural – Linear – Elastic - Isotropic
Or issue:
ET,1,BEAM189
MP,EX,1,210E3
MP,PRXY,1,0.3
Constrain the UX, UY, and UZ directions at keypoints 1 and 3, and then constrain only
the UZ direction at keypoint 2:
6.
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Main Menu > Preprocessor > Loads > -Loads- Apply > -Structural- Displacement > On keypoints +
Or issue:
DK,1,UX,0,,,UY,UZ
DK,3,UX,0,,,UY,UZ
DK,2,UZ,0
INTRODUCTION TO ANSYS 6.0 - Part 2
4.
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7. Nonlinear Analysis - Large Deflection
Arched Beam
Apply a force of 20,000 N in the negative Y direction at keypoint 2:
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Main Menu > Preprocessor > Loads > -Loads- Apply > -Structural- Force/Moment > On keypoints +
Or issue:
FK,2,FY,-20000
INTRODUCTION TO ANSYS 6.0 - Part 2
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7. Nonlinear Analysis - Large Deflection
Arched Beam
Define the beam's section properties:
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Main Menu > Preprocessor > Sections > -Beam- Common Sectns ..
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ID = 1
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Sub-Type = <rectangle>
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Offset = Centroid
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B = 25
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H = 12.5
• [OK]
Or issue:
SECTYPE,1,BEAM,RECT
SECOFFSET,CENT
SECDATA,25,12.5
INTRODUCTION TO ANSYS 6.0 - Part 2
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7. Nonlinear Analysis - Large Deflection
Arched Beam
Assign attributes, including the orientation keypoint, to the lines:
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Main Menu > Preprocessor > -Attributes- Define > All Lines ...
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MAT = 1
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TYPE = “1 BEAM189”
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SECT = 1
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Pick Orientation Keypoint(s) = “yes”
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[OK]
• Pick keypoint 4, then [OK]
Or issue:
LATT,1, ,1, ,4, ,1
INTRODUCTION TO ANSYS 6.0 - Part 2
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7. Nonlinear Analysis - Large Deflection
Arched Beam
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Main Menu > Preprocessor > -Meshing- Size Cntrls > -ManualSize- -Lines- All Lines ...
Or issue:
LESIZE,ALL,,,10
11. Mesh all the lines:
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Main Menu > Preprocessor > -Meshing- Mesh > Lines +
Or issue:
LMESH,ALL
12. Turn /ESHAPE on and set /EFACET to two, and then plot the elements:
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Utility Menu > PlotCtrls > Style > Size and Shape ...
Or issue:
/ESHAPE,1
/EFACET,2
EPLOT
INTRODUCTION TO ANSYS 6.0 - Part 2
10. Set 10 element divisions on all lines:
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7. Nonlinear Analysis - Large Deflection
Arched Beam
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Pick the “SAVE_DB” button in the Toolbar
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Main Menu > Solution > -Solve- Current LS
Or issue:
(or select: Utility Menu > File > Save as Jobname.db)
SAVE
/SOLU
SOLVE
14. Select node number 2 (mid-span node), then enter POST1 and print the nodal
displacements:
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Utility Menu > Select > Entities ...
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Main Menu > General Postproc > List Results > Nodal Solution ...
Or issue:
NSEL,S,,,2
/POST1
PRDISP
INTRODUCTION TO ANSYS 6.0 - Part 2
13. Save the database and obtain the linear solution:
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7. Nonlinear Analysis - Large Deflection
Arched Beam
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Utility Menu > Select > Everything
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Main Menu > Solution > Sol’n Control ..
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Activate “Large Displacement Static” under Analysis Options
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Set Number of substeps = 10
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[OK]
Main Menu > Solution > -Solve- Current LS
Or issue:
ALLSEL
/SOLU
NLGEOM,1
NSUBST,10
SOLVE
Convergence Graph
INTRODUCTION TO ANSYS 6.0 - Part 2
15. Select everything and enter the solution processor to solve the nonlinear solution:
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7. Nonlinear Analysis - Large Deflection
Arched Beam
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Utility Menu > Select > Entities ...
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Main Menu > General Postproc > List Results > Nodal Solution ...
Or issue:
NSEL,S,,,2
/POST1
PRDISP
INTRODUCTION TO ANSYS 6.0 - Part 2
16. List the displacement of node 2:
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7. Nonlinear Analysis - Large Deflection
Arched Beam
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Utility Menu > Select > Everything
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Utility Menu > PlotCtrls > Style > Displacement Scaling …
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Main Menu > General Postproc > Plot Results > -Contour Plot- Nodal Solu …
Or issue:
ALLSEL
/DSCALE,1,5
PLNSOL,U,Y
INTRODUCTION TO ANSYS 6.0 - Part 2
17. Select everything and set displacement scaling to 5, then plot the UY displacement
results:
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7. Nonlinear Analysis - Large Deflection
Arched Beam
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Utility Menu > PlotCtrls > Animate > Deformed Results …
Or issue:
ANCNTR,10,0.5
19. Save and exit ANSYS:
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Pick the “QUIT” button
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in the Toolbar
Or issue:
FINISH
/EXIT
INTRODUCTION TO ANSYS 6.0 - Part 2
18. Animate the UY displacement results:
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