Page History

...

1. In ANSYS, you need to specify E and I separately. You can pick them independently as long as you get the desired EI. You specify I by specifying the cross-section as we saw in the preceding tutorial. To keep things simple, just pick a square cross-section as in the tutorial. Keep the cross-section dimensions small compared to the beam length to get a slender beam. ANSYS uses the Timoshenko beam formulation which is more general than the Euler-Bernoulli formulation. The difference between the two formulations becomes significant only when the beam is non-slender.
2. Model the geometry using four lines. You will need to have vertices where you will be applying forces, moments or displacement constraints.
3. Apply a distributed load using Line Pressure as shown above.
4. Apply the simply supported constraints using Supports > Displacement. For example, the settings in the figure below can be used to apply the simply supported constraint at A or C. Note that ANSYS uses a generalized 3D beam formulation which includes z displacements. Since we don't have any deformation in the z direction, you can set the z displacements in simply supported conditions to zero.
5. In the ANSYS model , you have to add an extra constraint by fixing the rotations about x and y axes at the right end (see snapshots below). Otherwise you might get a solver pivot error. This is because ANSYS is using a 3D beam element with these additional rotations as dof's. Adding the fixed rotation will zero out these additonal dof's.
   
   
   
   
   
   
   
   
6. ANSYS constructs the bending moment from the reactions rather than by differentiating the deformed shape. The former is a more accurate way of calculating the bending moment distribution The two approaches give the same result on a fine mesh.
7. ANSYS uses mid-side nodes by default which gives a higher-order interpolation than the common cubic interpolation. So you get mesh converged results with relatively few beam elements. To get the cubic interpolation for beam elements, you can drop mid-side modes. You don't need to do this for this problem.
   
   
   
   

...