large deflection arched beam workshop 7 nonlinear analysis
TRANSCRIPT
Large Deflection Arched Beam
Workshop 7
Nonlinear Analysis
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7. Nonlinear Analysis - Large Deflection
Arched Beam
Description
• 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.
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7. Nonlinear Analysis - Large Deflection
Arched Beam
Loads and Material Properties
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7. Nonlinear Analysis - Large Deflection
Arched Beam
1. 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.
– 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.
– Utility Menu > WorkPlane > Change Active CS to > Global Cylindrical
– Main Menu > Preprocessor > -Modeling- Create > Keypoints > In Active CS …
– 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
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7. Nonlinear Analysis - Large Deflection Arched Beam4. Define lines (arcs) from keypoints 1 to 2 and keypoints 2 to 3:
– Main Menu > Preprocessor > -Modeling- Create > -Lines- Lines > In Active Coord +– Or issue:
L,1,2
L,2,3
5. Define the element type to be BEAM189, and then define material properties (EX=210e3 MPa, PRXY=0.3):
– 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
6. Constrain the UX, UY, and UZ directions at keypoints 1 and 3, and then constrain only the UZ direction at keypoint 2:
– 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
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7. Nonlinear Analysis - Large Deflection Arched Beam
7. Apply a force of 20,000 N in the negative Y direction at keypoint 2:– Main Menu > Preprocessor > Loads > -Loads- Apply > -Structural- Force/Moment > On keypoints +
– Or issue:
FK,2,FY,-20000
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7. Nonlinear Analysis - Large Deflection Arched Beam
8. Define the beam's section properties:– Main Menu > Preprocessor > Sections > -Beam- Common Sectns ..
• ID = 1
• Sub-Type = <rectangle>
• Offset = Centroid
• B = 25
• H = 12.5
• [OK]
– Or issue:
SECTYPE,1,BEAM,RECT
SECOFFSET,CENT
SECDATA,25,12.5
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7. Nonlinear Analysis - Large Deflection Arched Beam
9. Assign attributes, including the orientation keypoint, to the lines:– Main Menu > Preprocessor > -Attributes- Define > All Lines ...
• MAT = 1
• TYPE = “1 BEAM189”
• SECT = 1
• Pick Orientation Keypoint(s) = “yes”
• [OK]
• Pick keypoint 4, then [OK]
– Or issue:
LATT,1, ,1, ,4, ,1
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7. Nonlinear Analysis - Large Deflection Arched Beam
10. Set 10 element divisions on all lines:– Main Menu > Preprocessor > -Meshing- Size Cntrls > -ManualSize- -Lines- All Lines ...
– Or issue:
LESIZE,ALL,,,10
11. Mesh all the lines:– Main Menu > Preprocessor > -Meshing- Mesh > Lines +
– Or issue:
LMESH,ALL
12. Turn /ESHAPE on and set /EFACET to two, and then plot the elements:– Utility Menu > PlotCtrls > Style > Size and Shape ...
– Or issue:
/ESHAPE,1
/EFACET,2
EPLOT
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13. Save the database and obtain the linear solution:– Pick the “SAVE_DB” button in the Toolbar (or select: Utility Menu > File > Save as Jobname.db)
– Main Menu > Solution > -Solve- Current LS
– Or issue:
SAVE
/SOLU
SOLVE
14. Select node number 2 (mid-span node), then enter POST1 and print the nodal displacements:
– Utility Menu > Select > Entities ...
– Main Menu > General Postproc > List Results > Nodal Solution ...
– Or issue:
NSEL,S,,,2
/POST1
PRDISP
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7. Nonlinear Analysis - Large Deflection Arched Beam
15. Select everything and enter the solution processor to solve the nonlinear solution:– Utility Menu > Select > Everything
– Main Menu > Solution > Sol’n Control ..
• Activate “Large Displacement Static” under Analysis Options
• Set Number of substeps = 10
• [OK]
– Main Menu > Solution > -Solve- Current LS
– Or issue:
ALLSEL
/SOLU
NLGEOM,1
NSUBST,10
SOLVE
Convergence Graph
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7. Nonlinear Analysis - Large Deflection Arched Beam
16. List the displacement of node 2:– Utility Menu > Select > Entities ...
– Main Menu > General Postproc > List Results > Nodal Solution ...
– Or issue:
NSEL,S,,,2
/POST1
PRDISP
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7. Nonlinear Analysis - Large Deflection Arched Beam
17. Select everything and set displacement scaling to 5, then plot the UY displacement results:
– Utility Menu > Select > Everything
– Utility Menu > PlotCtrls > Style > Displacement Scaling …
– Main Menu > General Postproc > Plot Results > -Contour Plot- Nodal Solu …
– Or issue:
ALLSEL
/DSCALE,1,5
PLNSOL,U,Y
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7. Nonlinear Analysis - Large Deflection Arched Beam
18. Animate the UY displacement results:– Utility Menu > PlotCtrls > Animate > Deformed Results …
– Or issue:
ANCNTR,10,0.5
19. Save and exit ANSYS:– Pick the “QUIT” button
in the Toolbar
– Or issue:
FINISH
/EXIT