Tutorial - Solving 2D Truss problem using Mechanical APDL (ANSYS)?

Sudhir Gill

9 Mar, 2012 07:47 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

We will go through these and solve the problem. I will suggest you to go through this tutorial before solving this problem. http://grabcad.com/questions/tutorial-2d-truss-analysis-in-mechanical-apdl-ansys-part-1

1. Step 1:

   Start ANSYS Mehchanical APDL.
   

   

2. Step 2:

   Click Preferences and select Structural & click OK.
   

   

3. Step 3:

   Now we have the first step i.e. Preprocessing. Goto Modeling >> Create >> Keypoints >> In active CS. We will now create Keypoints for the problem.
   

   

4. Step 4:

   Input keypoints
   x y z
   1. 0 0 0
   2. 3000 3000 0
   3. 6000 0 0
   4. 0 3000 0
   5. 6000 3000 0
   6. 3000 6000 0
   7. 0 6000 0
   8. 6000 6000 0
   9. 0 9000 0
   10. 3000 9000 0
   11. 6000 9000 0
   12. 0 12000 0
   13. 3000 12000 0
   14. 6000 12000 0
   15. 3000 15000 0
   

   

5. Step 5:

   We have the keypoints plotted.
   

   

6. Step 6:

   We have to create the lines. Goto Modeling >> Create >> Lines >> Lines >> in active Coord.
   

   

7. Step 7:

   Create lines. Click OK.
   

   

8. Step 8:

   Now we have to Define the mesh size. Goto >> Meshing >> Size Cntrls >> Manual Size >> Lines >> All Lines.
   

   

9. Step 9:

   Input number of element divisions = 1 and click OK.
   

   

10. Step 10:

    Now we have to define the element type. Goto Element type >> Add/Edit/Delete.
    

    

11. Step 11:

    Click Add and then select Link >> 3D finit stn 180. This is link 180. Click OK and then close.
    

    

12. Step 12:

    Now we have to define the cross section of the truss. Goto Real Constants >> Add/Edit/Delete.
    

    

13. Step 13:

    Click Add and then define Cross-sectional area = 3500.
    

    

14. Step 14:

    Now we will create the mesh of this truss. Goto Meshing >> Mesh >> Lines.
    

    

15. Step 15:

    Click Pick all.
    

    

16. Step 16:

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

    

17. Step 17:

    Goto Structural >> Linear >> Elastic >> Isotropic.
    

    

18. Step 18:

    Input EX=200000, PRXY=0. Click OK and then close.
    

    

19. Step 19:

    Now the second step i.e. Solution. Goto Solution >> Analaysis Type >> New Analysis.
    

    

20. Step 20:

    Select Static and then click OK.
    

    

21. Step 21:

    Now we will define the fixed supports. Goto Define loads >> Apply >> Structural >> Displacement >> On Keypoints.
    

    

22. Step 22:

    Select two fixed lower keypoints.
    

    

23. Step 23:

    Click OK and then select ALL DOF and click OK.
    

    

24. Step 24:

    Now Define Loads >> Apply >> Structural >> Force/Moment >> On keypoints.
    

    

25. Step 25:

    Select top keypoints. Click OK.
    

    

26. Step 26:

    Input force value = 5000N. Click OK.
    

    

27. Step 27:

    Now save the project.
    

    

28. Step 28:

    Now second step i.e. Solution. Solution >> Solve >> Current LS.
    

    

29. Step 29:

    Click OK.
    

    

30. Step 30:

    Click Close.
    

    

31. Step 31:

    Now third step i.e. Post proecessing. General postproc >> List results >> Reaction Solu.
    

    

32. Step 32:

    Click OK.
    

    

33. Step 33:

    Now we have the reaction on the 1st and 2nd node which are fixed.
    

    

34. Step 34:

    Under Plot Results >> Deformed shape.
    

    

35. Step 35:

    Select Def+Undeformed and click OK.
    

    

36. Step 36:

    We have deformation plot.