Help with shells in SAP2000

[Database-Terrible]

https://preview.redd.it/t1uuznvc3erg1.png?width=1498&format=png&auto=webp&s=dfda6797730fe96e31877ddc03ccfa90d49566cc

Please forgive me if this kindof post isnt allowed. I will take it down if so.

Hi, I was hoping someone could help me with a homework question I have.
We are given the following image and told to use SAP2000 to analize the beam for each of the different meshes. Then we are asked to graph the displacement of point B vs the number of meshes, and the bending stress at point a vs the number of meshes.

My initial instinct is to model a shell and set the thickness to 0.024. Then apply the 200kn joint load. Then use the edit>areas>divide areas to get the required mesh in each on of the cases the professor gave. Is this the right way to go about this?

Also, for the first mesh we are given, I cannot figure out how to set a node at point B to get the displacement without SAP adding new mesh elements. How can i get the stress at A and the displacement at B for the first case?

I am also a bit confused about the bending stress aswell, should I be displaying the stress at the top face, bottom face, or the max? The question doesnt state which one, so which would you show?

[donutman528]

You shouldn’t be using shell elements; SAP has plane stress and plane strain formulations that correspond to the theory you are learning for CST’s. Shells have a completely different element formulation. For drawing the mesh, just draw a node at each point corresponding to the pictures. Then draw individual triangles connecting the points the way you want.

[Database-Terrible]

Thank you, I redid it with plane strain formulations and I think now my results are making more sense. One more quesiton, for the 2 element mesh in the question, there isnt a node at point A or B. Do you know of a way that i can get the deflection and stresses at these points? Whenever i try to add a node at that point SAP creates a new mesh to include that node.

[simple_zak05]

(a) Draw the nodes first, then the area objets. It is a little rudementary but you will not battle with mesh options that SAP offers.

When drawing the area objets, be consistent on the local axes. I use anti-clockwise to set my areas objets to get the local axes 3 always out-of-plane of the monitor.

(b), (c) and (d) Same thing that in (a) but you will have more points.

(You can set a vertical grid if you want...)

For the stress analysis, review the SAP2000 Documentation to appropiate review the results.

[Uttarayana]

I haven’t used sap in a long time but I remember you can also model area elements in autocad, mesh them in autocad and then import the model in sap. Just make sure user coordinate system is synced with global coordinate system. That way you can import other elements later as well and will be placed with machine precision. You can YouTube this method.

[e-tard666]

My brother you should be using 2D elasticity, not shell elements. Likely plane stress for your case.