I am analyzing an existing monorail (S-section) as a series of shell (plate) elements in RE. I have pin supported nodes at the top flange with crane wheel node loads on the bottom flange. I have a couple questions about this approach:
1) Is the general configuration within the scope of RE? The preliminary results are about what a person would expect but I am not wholly familiar with all of the ins and outs of RE FE.
2) Is it possible to model a web doubler plate? I have bending about the web that I would like to mitigate with a web doubler.
3) Is it possible to model the tapered flange as a shell element?
Thanks in advance!
If you are modeling the section using small shells and if you support multiple nodes at the end with nodal restraints, then you will effectively be creating a fixed end condition. Pinning a single node at the centroid of the shape would be one way to create a pin support for the beam.
A doubler plate could be approximated by making the shells in the area of the plate thicker. I suppose you could also do it with a second, slightly offset plate, but then you would have to link the offset plate back to the web plate somehow.
You can create trapezoidal shaped shells to taper a flange. if you wanted to taper the thickness of the shells, this would have to be done step-wise since each plate is constant thickness.
See also: https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/7652/ram-elements-shells-faq
That is tremendously helpful, thank you!
The purpose of the pinned nodes at the top flange is to simulate a four bolt connection, also does a pretty good job of getting me my bolt forces under the different loading conditions.
As for creating a trapezoidal shell for the flange, could you elaborate more on this? Would that require four nodes at each end and then a proper sequence of node selection? The trapezoidal section also raises the question as to what a person would need to set the shell thickness to.
You might consider point springs for your bolts instead of pins, but it won't affect things much.
Yes, I was thinking that you would alter the node locations to create the tapering flange width. There are lots of tools to help with node adjustment/alignment if needed, or you can use Excel to calculate values and paste them into Ram Elements.
I see now I "mis-spoke" previously. My question about tapering the flange applies to the thickness of the flange, not the width. I am dealing with an S-flange section and would like to account for the benefit of the thicker flange at the web as this would decrease my bending stresses in the flanges.
You'll have to average the flange as a rectangular section then.
Thats what I needed to know, thank you!