Nailing two box beams

If V ≠ 0, the bending moments at the ends of the segments must be unequal. Recall V = ΔM/Δx.

For this example, we will assume that the moment acting on the front side is a little bit larger (ΔM) than the moment acting on the back side. Accordingly, the bending stresses on the front side are greater than those on the back side.