Section Modulus calculation and optimization

Aim: To find the section modulus of the hood and optimise it to improve the overall section modulus.

Section Modulus: The section modulus (S) is geometric property of the cross section used for designing beams and flexural members.

Section Modulus is defined as the ration of total moment resisted by the section to the stress in the extreme fibre which is equal to yield stress.

        There fore

          S = I/Y, Where

S = Section modulus (mm^3)

I = Moment of Inertia of the section about the bending axis. (mm^4)

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

Neutral axis: When beam is subjected to pure bending the top most fibres of the beam are subjected to maximum compression, while the bottom most fibres of the beams are subjected to maximum tension.

• Before Optimization:

Moment of inertia(min) = 2.6784×10^5 mm^4

Y=880.1281/2= 440.064mm

S=I/Y

S=2.6784×10^5/440.064= 608.63 mm^3

• After Optimization:

The hood inner panel curve is offset by 0.5mm outwards and section inertia analysis is done.

Moment of inertia(min) = 2.7178×10^5 mm^4

Y=880.1281/2= 440.064mm

S=I/Y

S=2.7178×10^5/440.064= 617.59 mm^3

Conclusion:

when comparing Before and after optimization cases we see that the section modulus value after optimization is higher. As we increase the section area, the moment of inertia & section modulus increases which means strength and load bearing capability increases.