Section Modulus calculation and optimization

Aim:- Calculate section modulus of hood design and improve hood's strength

Section modulus:- It is geomatric property for a given cross section which used in design, where bending moment occurs, In simple terms the section modulus is the ratio of bending moment to bending stress for any solid material.

Section modulus formula:- S=I/Y

Where,

S = Section modulus

I = Moment of inertia

Y = Distance between neutral axis and extreme fibres

For finding section modulus here are some steps:-

1. First need to find moment of intertia (I) ( which we get from NX software for hood design )
2. then also find distance (Y) ( which also we get from NX software for hood design )
3. then use formula of section modulus which shows upside for calculation

As per below pictures we can see value of, moment of inertia (I) and distance (Y) and moment of inertia has two values one is minimum and second is maximum.

current hood design:-

From current hood design,

Moment of inertia (I):-

I_{min = 6.579 x 10^3 (mm^4)}

I_{max = 8.336 x 10^5 (mm^4)}

Distance (Y):- (Note:- For using (Y) value in formula we need to take half of it's value)

Y = 487.113/2

Y = 243.555 mm

Section modulus for min. = 6.579 x 10^3 / 243.555

                                         = 27.012

                                  S_min = 0.027012 x 10^3

Section modulud for max. = 8.336 x 10^5 / 243.555

                                          = 3422.635

                                   S_max= 3.422635 x 10^3

As we see for current hood design section modulus range is 0.027012 x 10^3 to 3.422635 x 10^3

Modified hood design:-

From modified hood design, (Note:- In modified hood design, I have increased draft value for increse hood strength)

Moment of inertia (I):-

I_{min = 7.3812 x 10^3 (mm^4)}

_{Imax = 8.3367 x 10^5 (mm^4)}

Distance (Y):- (Note:- For using (Y) value in formula we need to take half of it's value)

Y = 487.113/2

Y = 243.555 mm

Section modulus for min. = 7.3812 x 10^3 / 243.555

                                         = 30.306

                                  S_min = 0.030306 x 10^3

Section modulud for max. = 8.3367 x 10^5 / 243.555

                                          = 3422.923

                                  S_max = 3.422923 x 10^3

As we see for modified hood design section modulus range is 0.030306 x 10^3 to 3.422923 x 10^3

Difference:-

before section modulus for min. = 0.027012 x 10^3

after section modulus for min. = 0.030306 x 10^3

before section modulus for max. = 3.422635 x 10^3

after section modulud for max. = 3.422923 x 10^3 

That's how increasing draft value we can see how section modulus value has also increased and this how also increase the strangth of hood.