Bending stress is proportional to

Answer 1

I searched for properties of

1" x 3" 11 gauge rectangular steel tubing, but that is an odd size. We

will have to calculate the section modulus (excluding corner radius):

S = bd^3 - b1d1^3/6d

b = 1"

d = 3"

b1 = 1 - 2x0.091 = 0.818

d1 = 3 - 2x0.091 = 2.818

S = [(1 x 3^3) - (0.818 x 2.818^3)] / (6 x 3) = 0.483 in^3

M (maximum bending moment) = [P (point load) x l (length)] / 4

Solving for P:

P = 4M/l

M = s x S

Where:

s (allowable bending stress) = .55 x yield strength of steel

To be conservative we will assume that the steel you have is 30,000 psi

M = .55 x 30,000 x 0.483 = 7,969 in-lb

P = 4 x 7,969 / 72 in = 442#

Answer 2

bending stress also depends upon the geometry of object ,as it is given by

BENDING STRESS/DISTANCE FROM THE NEUTRAL AXIS

=

BENDING MOMENT / MOMENT OF INERTIA

But to solve the problems related to object made of c-45 steel ,the maximum stress is taken as 140 mpa.

Answer 3

Section Modulus.