1 Answers
The neutral axis is an axis in the cross section of a beam or shaft along which there are no longitudinal stresses or strains. If the section is symmetric, isotropic and is not curved before a bend occurs, then the neutral axis is at the geometric centroid. All fibers on one side of the neutral axis are in a state of tension, while those on the opposite side are in compression.
Since the beam is undergoing uniform bending, a plane on the beam remains plane. That is:
γ x y = γ z x = τ x y = τ x z = 0 {\displaystyle \gamma _{xy}=\gamma _{zx}=\tau _{xy}=\tau _{xz}=0}
Where γ {\displaystyle \gamma } is the shear strain and τ {\displaystyle \tau } is the shear stress