# Calculating max load of square tube (steel)

by drewjohn
 Sci Advisor P: 1,498 Calculating max load of square tube (steel) No, that's what you're looking for. It's a textbook problem really. Calculate the maximum bending moment in your beam. Then apply the bending stress equation to find the maximum stress. Via http://www.engineeringtoolbox.com/be...on-d_1312.html the maximum stress in a simply supported distributed loaded beam is: $$\sigma = \frac{y q L^2}{8 I}$$ Where y is the perpendicular distance from the neutral axis, q is the load in force/length, L is the length of the beam, and I is the area moment of inertia of the cross section. Be careful though, depending on the application. Yield strength is the strength assuming one cycle. If this beam is to be loaded and unloaded, then you should calculate a fatigue life, and then still use a safety factor. Good luck,