I have sized 2 1/2 x 2 1/2 x 1/4" angle iron for a project, I wonder if an angle with a longer leg parallel to the load would be as strong but lighter,ie 3 1/2 x 1 1/2 x 3/16
- posted
14 years ago
I have sized 2 1/2 x 2 1/2 x 1/4" angle iron for a project, I wonder if an angle with a longer leg parallel to the load would be as strong but lighter,ie 3 1/2 x 1 1/2 x 3/16
Ask an engineering question, get an engineering answer: That Depends.
Just how are you going to be loading the angle? How well are you supporting it from twisting? If you want it to resist a bending moment (which I assume is what you want), why aren't you using a 'U' or 'I' section, or a tube?
All other things being equal the answer is NO.
Wolfgang
I'll have to plead ignorant. The angle was chosen because of availability and ease of working other materials around it, but this can be changed. The steel will be bolted to 3/4" plywood with an even load of 450# along a 6ft length. What would be the most efficient shape and size to use?
To clarify, the steel is supported at each end and bolted to plywood to control twisting. the load is applied to plywood with the steel on the opposite side.
Do you mean like braces under a plywood table?
Paul
Heh, the gang is making you jump through hoops!
Your original premise that a longer leg down might increase the strength is a good start but angle iron has some quirks in the strength department. When used to support shelves, the lower leg tends to buckle when overloaded. So even though the section modulus might be higher with a longer leg, the thinner cross section will let it buckle under a lighter load than a shorter leg version. This also means that nobody really wants to say it will (or won't) work in your application
The other problem with angle iron is that the upper and lower chords within the angle are wildly unequal. Plenty of metal in the upper (horizontal leg), very little in the lower leg (just thin metal)
A rectangular tube shape is usually a better choice. Start with one about the same weight per foot as the angle.
snipped-for-privacy@yahoo.com wrote:
The OP wrote "with the longer leg PARALLEL to the load", ie. NOT at right angles to the load nor vertical. Therefore my answer was NO.
I'd use a bent-up channel section of the appropriate section modulus.
Wolfgang
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.