Section Modulus calculation and optimization

Section Modulus

• It is defined as the ratio of the moment resisted by the section to the stress in the extreme fibre.
• It gives an idea that most of the work in bending is being done by the extreme fibres of the beam,i.e. the top and bottom fibres of the section.
• The distance of the fibres from top to bottom is therefore built into the calculation.
• If the section modulus increases the moment of resistance increases & hence its load bearing capacity.
• With a higher section modulus than another will be stronger and capable of supporting greater loads.

Calculation of section modulus :

1. To calculate moment of inertia , I have taken a section along a plane then used section inertia analysis for maximum.
2. Once the moment of inertia is calculated then for distance click on the measurement for the distance between the centre and end of the section.
3. Now everything we got put the information into the formula S=I/Y where

S = section modulus

Y = perpendicular distance

I = Moment of inertia

I = 1.41x 10^4 mm^4

Y = 437.78 mm

S = 1.41x 10^4 / 437.78

So therefore S= 32.20 mm^3

To improve section modulus I made some changes in my hood and bleow are the images and tables for the same:

By offsetting the inner panel by 0.5mm the moment of inertia increased from 1.41x10^4 mm^4 to 1.43x10^4 mm^4

By offsetting inner panel by 2 mm the moment of inertia increased from 1.43x10^4 mm^4 to 1.52x10^4 mm^4

Offset	Moment of inertia	Distance	Section modulus
0 mm	1.41X10^4 mm^4	437.78 mm	32.20 mm^3
0.5 mm	1.43X10^4 mm^4	437.78 mm	32.66 mm^3
2 mm	1.52X10^4 mm^4	437.78 mm	34.72 mm^3

The Area moment of inertia shows how it resists the bending force geater the material above the neutral axis will lead to the greater moment of inertia ,so when there is an external force applied to the part with greater MOI there will be less damage to the system. Therefore as the moment of inertia is directly proportional to section modulus as the moment of inertia increases, section modulus also increases along with it.

Conclusions :

Section of modulus for my hood is 32.20 mm^3. After making some changes to the section, the modulus has increased and now it's even with a larger force.