Section Modulus calculation and optimization

A BRIEF ABOUT SECTION MODULUS

Section Modulus is defined as the Area Moment of Inertia divided by the Distance between Neutral Axis and the Boundary or Extreme End of the Body/Section.

`S=I/(y)`

where, I = Moment of Inertia of the Section,

y = Distance between Neutral Axis and the Extreme End of the Section.

Section modulus is a geometric property for a given cross-section used in the design of beams or flexural members. Other geometric properties used in design include area for tension and shear, radius of gyration for compression, and second moment of area and polar second moment of area for stiffness. Any relationship between these properties is highly dependent on the shape in question. Equations for the section moduli of common shapes are given below. There are two types of section moduli, the elastic section modulus and the plastic section modulus. The section moduli of different profiles can also be found as numerical values for common profiles in tables listing properties of such.

For general design, the elastic section modulus is used, applicable up to the yield point for most metals and other common materials.

The elastic section modulus is defined as S = I / y, where I is the second moment of area (or area moment of inertia, not to be confused with moment of inertia) and y is the distance from the neutral axis to any given fibre. 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. It is also often used to determine the yield moment (M_y) such that M_y = S ⋅ σ_y, where σ_y is the yield strength of the material.[1-reference here]

SECTION OF THE HOOD INNER AND OUTER PANAL

SECTION INERTIA ANALYSIS

LENGTH OF THE SECTION

LENGTH OF THE SECTION = 487.4083mm

y=487.4083/2=243.2041mm

Therefore,

SECTION MODULUS MAXIMUM = 8.456229003e+05/243.2041 mm^3 = 3477.009 mm^3

SECTION MODULUS MINIMUM = 3.43525111e+03/243.2041 mm^3 = 14.12497 mm^3

MODIFIED SECTION Of HOOD

SECTION MODULUS MAXIMUM = 8.474724956e+05/243.2041 mm^3 = 3484.618 mm^3

SECTION MODULUS MINIMUM = 3.5808707e+03/243.2041 mm^3 = 14.7237 mm^3

As you can Notice The Section modulus has increased minimally overall. However, the forefront section is weaker than the back section in the Modified design. This is to ensure the passenger safty in a frontal crash. Comparizon of front and back section is done below.

front section

before:

After:

back section

before:

After: