Section Modulus calculation and optimization

Section Modulus and Optimization.

Section modulus of a cross section is the quantifying property of the geometry. It is the ratio of second order of moment of inertia to the distance between the neutral axis to its farthest point. Higher the value of section modulus better is the stiffness. Hence, it is more resistant to bending and deformation. Section modulus can be improved by changing the geometry of the cross section without any other changes in the material or quantity of material.

Section modulus (S) = I(min)/Y

I(min) = Second moment of inertia

Y= distance from neutral axis to farthest point

Following are the few changes made to the geometry along with the effect on the bending moment.

Given Y= 445.77mm

1. Original section with no changes to the geometry.

I(min) = 1.5873 x 10^6 mm^4

S = I(min)/Y

S= (1.5873 x 10^6)/445.77

S= 3560.80 mm^3

2. Changing the embossing depth of the original section from 10mm to 15mm

I(min) = 1.6571 x 10^6 mm^4

S = I(min)/Y

S= (1.6571 x 10^6)/445.77

S= 3717.38 mm^3

3. Changing the offset by offsetting it 2mm more from the outer panel along with the changed emboss depth.

I(min) = 1.6772 x 10^6 mm^4

S = I(min)/Y

S= (1.6772 x 10^6)/445.77

S= 3762.48 mm^3

4. Keeping the original section, with change in offset as above.

I(min) = 1.6062 x 10^6 mm^4

S = I(min)/Y

S= (1.6062 x 10^6)/445.77

S= 3603.2 mm^3

	Y (mm)	I(min) (10^6 mm ^4)	S = I(min)/Y mm^3
1	445.77	1.5873	3560.80
2	445.77	1.6571	3717.38
3	445.77	1.6772	3762.48
4	445.77	1.6062	3603.2

Conclusion:

We tried changing the geometry to increase the bending moment of the cross-section. Following are some of the points we can conclude.

1. It is observed that increasing the offset and depth of the emboss gives us the best result.
2. Increasing the offset does not add a lot of strength to the body. On top of that, increasing the offset may not be a good idea as it will only cause more noise due to vibration.
3. It can also be seen that by just increasing the depth of the emboss of the original section the strength is greatly increased, which is not much different from the third iteration.