Tutorial - 2D Truss analysis in Mechanical APDL (ANSYS) Part 1?

Sudhir Gill

9 Mar, 2012 07:23 AM

In general, a finite element solution may be broken into the following three stages.

1. Preprocessing: defining the problem;
- Define keypoints/lines/areas/volumes
- Define element type and material/geometric properties
- Mesh lines/areas/volumes as required

2. Solution: assigning loads, constraints and solving;

3. Postprocessing:
- Lists of nodal displacements
- Element forces and moments
- Deflection plots
- Stress contour diagrams

In this tutorial we will go through first step.

1. Step 1:

   Start Ansys Mechanical APDL.
   

   

2. Step 2:

   Click Preferences and select Structural since we are going to have structural analysis. Click OK.
   

   

3. Step 3:

   Now we have to plot keypoints. Under Preprocessor >> Modeling >> Create >> In active CS.
   

   

4. Step 4:

   Now we have to input Keypoints. Input keypoint number 1 and XYZ co-ordinates and click Apply.
   

   

5. Step 5:

   Enter 2nd Keypoint X=500, Y=1000. Z will remain zero since we have 2D Bridge Truss. Click Apply.
   

   

6. Step 6:

   Enter 3rd Keypoint X=1000,Y=0. Click Apply.
   

   

7. Step 7:

   Enter 4th Keypoint X=1500,Y=1000. Click Apply.
   

   

8. Step 8:

   Enter 5th Keypoint X=2000,Y=0. Click OK
   

   

9. Step 9:

   Now we have keypoints plotted. We have to create lines along these keypoints. Goto Modeling >> Create >> Lines >> In Active Coord.
   

   

10. Step 10:

    Now select the kepoint by clicking them and click other keypoint to create line. Create the members. Click OK.
    

    

11. Step 11:

    Now we have to define the Element type. i.e. Beam. Under Element type >> Add/Edit/Delete.
    

    

12. Step 12:

    Click Add.
    

    

13. Step 13:

    Under link select 3D finit stn. This is link 180 which we are going to use. In older version of ANSYS 2D Spar is used for defining link 180. Click OK.
    

    

14. Step 14:

    Now we have to define the cross section of the members. Under Real constants >> Add/Edit/Delete.
    

    

15. Step 15:

    Click Add.
    

    

16. Step 16:

    Input Cross-sectional area = 3250. Keep the default settings and click OK and then close.
    

    

17. Step 17:

    Now we have to define the material properties. Goto Material props >> Material models.
    

    

18. Step 18:

    Under Material model available goto Structural >> Linear >> Elastic >> Isotropic.
    

    

19. Step 19:

    Input EX=200000 PRXY=0. These are material properties Elasticity and Poisson Ratio. Click OK and then close.
    

    

20. Step 20:

    Now we have to define the mesh size for the structure. Goto Meshing >> Size CNTRLS >> lines >> All lines. Input no. of divisions = 1. Click
    

    

21. Step 21:

    Now we have to mesh the lines. Goto Meshing >> Mesh >> Lines.
    

    

22. Step 22:

    Click Pick all to select all lines.
    

    

23. Step 23:

    The lines become blue which means the mesh has been created along the members.
    

    

24. Step 24:

    Since the first part of the tutorial is done we have to save the project. Under File >> Save as.
    

    

25. Step 25:

    Save the document to My Documents or any other Directory. If we don't save the document the Solution will not be performed.

    Second part of the tutorial http://grabcad.com/questions/tutorial-2d-truss-analysis-in-mechanical-apdl-ansys-part-2.