Section Modulus calculation and optimization

SECTION MODULUS CALCULATION AND OPTIMISATION

OBJECTIVE

• To calculate the section modulus for the previously designed hood.
• To come up with a new section that has imprved section modulus.

SECTION MODULUS

Section Modulus is the geometric property of the given cross-section of any shaft or beam structures. It is the direct measure of the strength of the shaft section or the beam section. Higher the section modulus of a structure, the more the resistive it becomes to bending.

Section modulus (S) is defined as the ratio of polar moment of inertia (I) to the radius of the shaft or the distance from the neutral axis to the outer fibres (y).

`S = I/y`

Calculation of Section Modulus in the predesigned hood

`I = 3.138xx10^5mm^4`

`y = 439.89mm`

`S = I/y = (3.138xx10^5mm^4)/(439.89mm) = 713.36mm^3`

Optimisation Attempts

Case 1 :- Offsetting the entire inner panel by 0.5 mm.

`I = 3.183xx10^5mm^4`

`y = 439.89mm`

`S = I/y = (3.183xx10^5mm^4)/(439.89mm) = 723.59mm^3`

Case 2 :- Offsetting only the embossed sections by 0.5mm

`I = 3.195xx10^5mm^4`

`y = 439.89mm`

`S = I/y = (3.195xx10^5mm^4)/(439.89mm) = 726.32mm^3`

Case 3 :- Ofsetting the inner panel by 0.5mm without changing the embosses

`I = 3.125xx10^5mm^4`

`y = 439.89mm`

`S = I/y = (3.125xx10^5mm^4)/(439.89mm) = 710.40mm^3`

CONCLUSION

Cross Section	Section Modulus
Predesigned Hood	`713.36mm^3`
Case 1	`723.59mm^3`
Case 2	`726.32mm^3`
Case 3	`710.40mm^3`

The highest increase in section modulus was found in case 2 where only the embosses were offsetted.