Stress calculation for angle subject to loads

[jsu0512]

Hi All,

I have a question how to calculate the stress in steel angle when its subjected to eccentric dead and wind load. I attached the diagram in this thread with dimension of the angle and the value of wind and dead loads. I also attached the stress value from the simulation in the Solidwork program. I'd like to know if there is hand calculation to verify this stress value from the program.

 

[phamENG]

There is. It's a pain. Somebody quite literally wrote a book about it.

Single Angle Design Manual by Whitney McNulty

 

[r13]

The member looks like a plate, as well as indicated by the result. How you bend the angle steel though? For simplified check, you can assume the member is a fixed cantilever, then check the stress using generalized flexural formula (from mechanics of materials textbook) for bending.

 

[JStephen]

You call it an angle, but it's just a bent piece of plate or flat bar.
Hand calc per beam equations, Mc/I + P/A, etc. Don't expect results to match finite element results.
On this kind of thing, if it's a one-off, you can easily spend a $1,000 analyzing a $2 part. If you're making a million of them or it's part of a NASA rocket, then go for it, otherwise, quick and simple analysis and oversize if required.

 

[rb1957]

yeah, I'd hand calc it. Calc the tang as a plate in bending, then calc the loads on the welds with some semi-rational assumption

another day in paradise, or is paradise one day closer ?

 

[r13]

Check your model, the result does not make good sense. Stress should be high along the welded edges, but it appears uniform over the entire plate except at the bend line.

 

[phamENG]

Hmm....that's what I get for not looking the picture. Yeah. This is easy. Just a flat bar. Not sure where to look in Canadian literature, but the AISC steel manual has a section for flat bar in the flexure chapter.

 

[dik]

I frequently make use of AISC information... and, occasionally Eurocode.

Dik

 

[Mohanlal0488]

As a number of people have mentioned I would also suggest looking at the AISC for the design considerations, there is a section on the design of flat plates and angles.

If you are not keen on reading through all the literature, a non-linear analysis taking into account geometric and non-linear material should also achieve good results. Keeping in mind that one would need to check for buckling failures, as these may occur before yielding.

General hand calculations as presented earlier in the thread neglect a number of attributes which need to be taken into account,thus from a design perspective, they are not adequate

 

[jsu0512]

Hi retired 13 and JStephen,

I've attached my hand calculation for analyzing the tensile stress in the steel plate assuming plate is in the cantilever state. Does this match with what you've described in your reply? Thank you for your feedback on this. I appreciate it.

 

[r13]

How about compression limit state? Otherwise looks fine.