Section Modulus calculation and optimization

Aim: To calculate the Section modulus of the hood model by using sectioning and then optimizing the hood panel to improve the overall section modulus for better strength of the hood.

Section Modulus: Section modulus is the direct measure of the strength of the steel. Section modulus is a geometric property for a given cross-section used in the design of flexural members. The more section modulus, the more the member is resistant to bending of the beam. If two beams are made of the same material and comparing the “section modulus” of two beams, the beam with bigger section modulus will be tougher and more capable to withstand larger loads than the smaller section modulus.

It is termed as the ratio of moment of inertia and distance from neutral axis to extreme fiber.

S = I/Y, where

S = Section Modulus (mm³)

I = Moment Of Inertia of the section about the bending axis. (mm⁴)

Y = Distance between the neutral axis and extreme end of the object (mm) .

Calculation:

Case 1: Before optimization

The hood which was already created is imported and the section inertia analysis is done.

We have to ensure that the curve obtained is closed.

Min MOI = 3.569 x 10⁵ mm⁴

Max MOI = 1.258 x 10⁸ mm⁴

Y = 483.088 / 2 = 241.54 mm

S = I (min) / Y

= 3.569 x 10⁵ / 241.54

S = 1477.602 mm³

Case 2: After optimization

The hood inner panel is offset by 0.5mm further outwards from the case 1 positon and Section modulus is done as same as Case1 for a closed curve.

Min MOI = 3.804 x 10⁵ mm⁴

Max MOI = 1.308 x 10⁸ mm⁴

Y = 483.088 / 2 = 241.54 mm

S = I (min) / Y

= 3.804 x 10⁵ / 241.54

S = 1574.894 mm³

Conclusion:

1. The section modulus value of case 2 is higher than the case 1.
2. As we increase the section area, the moment of inertia & section modulus increases which means strength of hood also increases.

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