Let us consider a beam loaded by two moments M (Fig. 35). No stresses occur in the neutral plane OO under pure bending as is well known. Accordingly, force interactions between upper and lower parts...

Let us consider a beam loaded by two moments M (Fig. 35). No stresses occur in the neutral plane OO under pure bending as is well known. Accordingly, force interactions between upper and lower parts of the beam in this plane are absent. Then one can divide the beam by the cross-section OO into two thinner beams and this will have absolutely no e¤ect on system operation.