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;
- 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
Start ANSYS Mehchanical APDL.
Click Preferences and select Structural & click OK.
Now we have the first step i.e. Preprocessing. Goto Modeling >> Create >> Keypoints >> In active CS. We will now create Keypoints for the problem.
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
We have the keypoints plotted.
We have to create the lines. Goto Modeling >> Create >> Lines >> Lines >> in active Coord.
Create lines. Click OK.
Now we have to Define the mesh size. Goto >> Meshing >> Size Cntrls >> Manual Size >> Lines >> All Lines.
Input number of element divisions = 1 and click OK.
Now we have to define the element type. Goto Element type >> Add/Edit/Delete.
Click Add and then select Link >> 3D finit stn 180. This is link 180. Click OK and then close.
Now we have to define the cross section of the truss. Goto Real Constants >> Add/Edit/Delete.
Click Add and then define Cross-sectional area = 3500.
Now we will create the mesh of this truss. Goto Meshing >> Mesh >> Lines.
Click Pick all.
Now we have to define the material properties. Goto Material Props >> Material models.
Goto Structural >> Linear >> Elastic >> Isotropic.
Input EX=200000, PRXY=0. Click OK and then close.
Now the second step i.e. Solution. Goto Solution >> Analaysis Type >> New Analysis.
Select Static and then click OK.
Now we will define the fixed supports. Goto Define loads >> Apply >> Structural >> Displacement >> On Keypoints.
Select two fixed lower keypoints.
Click OK and then select ALL DOF and click OK.
Now Define Loads >> Apply >> Structural >> Force/Moment >> On keypoints.
Select top keypoints. Click OK.
Input force value = 5000N. Click OK.
Now save the project.
Now second step i.e. Solution. Solution >> Solve >> Current LS.
Now third step i.e. Post proecessing. General postproc >> List results >> Reaction Solu.
Now we have the reaction on the 1st and 2nd node which are fixed.
Under Plot Results >> Deformed shape.
Select Def+Undeformed and click OK.
We have deformation plot.