How to reduce shear stress in a beam

[alexteplyaxins]

Homework Statement

Determine the largest internal shear force resisted by the bolt.

Relevant Equations

Apply equibrilium state.

 

[osilmag]

What are the sums of the forces for each case?

 

[alexteplyaxins]

What are the sums of the forces for each case?

I just can solve problem $a$ by apply equilibrium of force and momentum to find $F_a$ and $F_b$. But with case b, I can't find third equation.
Thank for read

 

[alexteplyaxins]

Boom, boom !

 

[haruspex]

I just can solve problem $a$ by apply equilibrium of force and momentum to find $F_a$ and $F_b$. But with case b, I can't find third equation.
Thank for read

Yes, b) is not fully specified. E.g. you could take away all of the shown forces and still have shear on the bolt resulting from tensions and compressions in the members on the left.
You could set one of those on the left as an unknown and find the shears in terms of that, then find the value of the unknown which minimises the maximum shear.