comparable beam strength aluminum vs steel rect tube

[chickering]

I'm designing a simple shop clamp jig with 2x3 1/8 wall alum rec hollow tube which spans a 4ft span, evenly loaded. What steel profile would give comparable deflection #'s. (steel's really cheap these days)

Jim

 

[par060]

EI of aluminum/EI of the steel.......

 

[Lion06]

par is right on. With the only variables being the section and material, the deflection is a function of EI. Since Ealuminum is about 1/3 Esteel, you need 1/3 the I req'd for the aluminum to get the same deflection in a steel member.

This is, of course, considering deflections only.