At yield, the maximum stress experienced in the section ( at the furthest points from the neutral axis of the beam ) is defined as the flexural strength.
22.
It is often reported using y = c, where c is the distance from the neutral axis to the most extreme fibre, as seen in the table below.
23.
Since the section modulus depends on the value of the moment of inertia, an efficient beam must have most of its material located as far from the neutral axis as possible.
24.
The stress distribution from the neutral axis is the same as the shape of the stress-strain curve of the material ( this assumes a non-composite cross-section ).
25.
The neutral plane is the position where the armature windings are moving parallel to the magnetic flux lines, that is why an axis lying in this plane is called as magnetic neutral axis ( MNA ).
26.
Where \ sigma is the stress, M is the bending moment, y is the distance from the neutral axis of the beam to the point under consideration and I is the second moment of area.
27.
In typical use, it is bonded to the tensile flange of the section, both increasing the stiffness of the section and lowering the neutral axis, thus greatly reducing the maximum tensile stress in the cast iron.
28.
This observation is the basis of the I-beam cross-section; the neutral axis runs along the center of the web which can be relatively thin and most of the material can be concentrated in the flanges.
29.
However, there are shear stresses ( ? ) in the neutral axis, zero in the middle of the span but increasing towards the supports, as can be seen in this function ( Jourawski's formula );
30.
The elastic section modulus is defined as Z = I / y, where I is the second moment of area ( or moment of inertia ) and y is the distance from the neutral axis to any given fibre.
