Finding dimensions of a beam using shear, moment, and moment of Inertia

[haleystew]

Homework Statement

Homework Equations

Moment of Inertia equation: I=(1/12)bh^3
Stress and Strain equations: Sigma= -(M*c)/I Tao = (V*Q)/(I*t)

The Attempt at a Solution

I know I need to use shear and moment diagrams to find the max moment so I can use the Stress diagram to find the Moment of Inertia to find the dimensions of the cross section, but I can't figure out how to get started. Any help would be great. Thank you.

 

[nvn]

Wouldn't you want to start by setting sigma in your equation equal to the given allowable bending stress? Give it a try.

 

[pongo38]

Can you draw a loading diagram for the cantilever you think has the most stress? Do you know a definition of bending moment that will enable you to draw the bending moment diagram?

 

[haleystew]

I am using the weight density to find the weight distribution over the entire area and then treating that as a simply supported beam. Will this work?

 

[pongo38]

If it is a simply supported beam, rather than a cantilever (as it says in the question !) where are the two supports?