CALCULATION OF SECTION MODULUS ON HOOD

AIM

To calculate the section modulus of the designed hood for analyazing it's strength. To make adjustments in the section modulus to increase the strength of the hood. The results are compared to give better understanding of the design.

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 is defined as the ratio of polar moment of inertia to the radius of the shaft or the distance from the neutral axis to the outer fibres.

Question

To come up with a new section that has improves the section modulus of the previous section and to mention what change has been made increase strength.

Formula used for calculating Section modulus

S=I/y

S = Section modulus

I = Moment of inertia

y = distance between the neutral axis and the extreme end of the object

The following values were obtained using NX CAD.

First case

MOI (max) = 4.5157e+06 mm^4

MOI (min) = 1.2367e+04 mm^4

Y=858.8425/2

= 429.42125 mm

S=I/Y

= 1.2367*10^4 mm^4 / 429.4212 mm

=28.79 mm^3

After 0.5mm Depth

MOI (max) = 4.5736e+06 mm^4

MOI (min) = 1.2882e+04 mm^4

Y=858.8425/2

= 429.42125 mm

S=I/Y

=1.2882*10^4 mm^4 / 429.4212 mm

S =29.99 mm^3

CONCLUSION

The difference can be seen with the two values given, the section modulus has increased with the change added. This means that the Moment of inertia increases which increases the strength.