Section Modulus calculation and optimization

Aim

To calculate section modulus of hood and optimize the design to have improved section modulus.

Section modulus:

Section modulus is a direct measure of a strength of any cross sectional area of an object about an reference axis.

The formula of section modulus is given by,

S=I / Ymax

Where,
I = Moment of inertia (mm^4)
Y = Distance between neutral axes and outermost fiber (mm)

Section Modulus Calculation:

For studying the section modulus we need the cross section of hood. For that I created a cross section using intersection curve.

MOI (max) =9.121291443e+07 (mm^4)

MOI (min) = 2.811711982e+05 (mm^4)

As per the section modulus equation,

S = I/Y

I = MOI (min) value is considered

Y = Total distance /2, Total distance =877.6283mm

Y = 877.6283/ 2

= 438.814 mm

Therefore,

S = 281171.1982 mm^4/437.784 mm

S =640.7525mm^3

CASE 2: After optimization

The hood inner panel’s curve is offset by 1mm outwards and section inertia analysis is done same as case 1 for a closed curve.

MOI (max) = 9.007190128e^07 mm^4

MOI (min) = 2.834597293e^05 mm^4

As per section modulus equation,

S = I / Y

I = MOI (min) value is considered

Y = Total distance /2, Total distance =877.6283mm

Y = 877.6383 / 2

= 438.814mm

Therefore,

S = 283459.729mm^4 /438.814 mm

S = 645.967 mm^3

Conclusion:

Hence when comparing case 1 & case 2,

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 and load material also increase