Section Modulus calculation and optimization

1.Section Modulus

Section modulus is a geometric property for a cross setion of a design. It is been used as a

geometric property include a area for shear and tension, radius of gyration for compression , and polar and mass

moment of inertia for area of stiffness. There are two types of section elastic section and plastic section

modulus.

Section modulus is a cross section for design. It gives the clear picture of the strength of the given part

with out knowing the strength of the material we cann't conclude that our design is good enough to be for PDC.

If the section modulus is higher then it has more strength if there is less section modulus it will be weaker in

strength.

Elastic Section Modulus

Elastic section modulus is the ratio of second moment of inertia and distance from the

neutral axis to any given fiber.It can also be defined as first moment of inertia. elastic section modulus deals

with elasticity.

formula is S = I/Y

S - section modulus

I - second moment of inertia

Y - distance from neutral axis to any particular distance.

Plastic Section Modulus

Plastic section modulus is the sum of the areas in may or may not equal partition

multiplied with the centriod of same areas. plastic section modulus deals with yield.

2.SECTION MODULUS FROM DESIGN

First taking the design of hood from that design we will go the curve section and selecting the

intersection curve option to get the intersection curve after getting that curve we need to convert that 3d

intersection to 2d curve. To convert that curve we need to go to sketch and need to select the sketch to

project that in 2d by going into the project curve in 2d . After projecting the curve we need to hide the 3d

intersection curve.

After hiding the 3d curve we need to focus in 2d project curve. from this curve we need to

make sure that there is no gaps in between for the hood design there will be gap between the hemming and

inner pannel we need to draw a curve to close that gaps. Now our section is ready for section inertia analysis

from search bar search for section inertia analysis. Then in that need to select exisisting plane for the section

inertia analysis. From that we need to select our curve which is needed for analysis.

For my section i got the resulsts shown below

MOI (MAX) = 1029792.531[mm^4]

MOI (MIN) = 3468.23864[mm^4]

now calculating the section modulus from neutral axis to last end.

s max = 1029792.531/478.261

= 2153.20 mm^3

s min = 3468.23864/478.261

= 7.25 mm^3

Section length = 2885.666 mm

Section Area = 57.647634848 mm^2

To increase section modulus ther should be less distance in the outer pannel and inner pannel there should

be less distance from the neutral axis will help in higher section modulus.