Section Modulus calculation and optimization

SECTION MODULUS:

It is termed as the ratio of the second moment of area and distance from N.A (Neutral axis) to the extreme fiber. Also, it is the measure of the strength of the given member. The stress in the outermost section of the beam is computed with the help of section modulus. It is indicated by S.

Section modulus is indicated as follows:

S=I/Y

Here, I is “moment of inertia” and y is the distance from the “ neutral axis ” to the top or bottom of fiber.

The Unit of a “section modulus” is in.3 (mm3)

Section modulus depends only on the cross-section shape of the structure. For symmetric sections, the value of “section modulus” is for both above and below of centroid of the fiber. An asymmetric section has two values for top and bottom of the fiber due to different distance from the centroid to the top and bottom of the material, the maximum “section modulus” is S max and the minimum section modulus is S min.

Section Modulus calculation of the Hood Design:

CASE 1: Initial Hood Design.

Area Moment of Inertia:  I(min)

MOI(min): 2.766372296e+005 mm^4

Y distance: 438.3mm

S=I/Y

S =  2.766372296e+005 mm^4  /  438.3mm
S  =  7.53118725458 mm^3

Section modulus is directly dependent on the area moment of inertia and the distance from the neutral axis. Hence, to improve the geometry of the carry more bending load, the section modulus can be improved by increasing the area MOI of a given section.
We can increase the section modulus just increasing the gap between the outer & inner panel.