Section Modulus calculation and optimization

AIM:

The objective of this project is to gain the knowledge on section modulus of a product and its calculation which is designed.

To increase the section modulus from the previous section of hood assembly.

WHAT IS SECTION MODULUS?

`S = I/Y`

I - Moment of Inertia, whose unit is `mm^4`

Y - Distance from the neutral element to the end of the object.

Following the formula ,we can tell section modulus is the ratio of moment of inertia to the distance of end of the object from the neutral element.

It can also be defined as the measure of the strength of the given member.It is a shape property of the given cross section of given shaft section.

The unit of section modulus is `mm^3`

WHY SECTION MODULUS CALCULATION IS IMPORTANT?

The value of section modulus is a reflection of the resistance to bending value.Hence to know the bending bearing capacity of a product it is convenient to calculate the section modulus.

More the section modulus value ,more the material is resistant to bending.

It is a measure of strength of the material.In a case , where beam is made up of two material finding the section modulus will help us to know the tougher material.

CALCULATION OF SECTION MODULUS IN HOOD:

The section modulus can calculated only for closed section in NX CAD.To create a closed section we create a intersection curve in the hood assembly.If a gap is detected in the curve we can fill it by line or curve.

The section will be look like as follows by neglecting the inner thickness:

Here we going to calculate the section modulus for the hood.But usually the section modulus is calculated for smaller area to increase the section strength locally.

We use tool named Section Inertia analysis which is available in NX CAD software for the section modulus calculation

I:

moment of inertia(max):4.47*10^6

moment of inertia(min):1.345*10^4

Then we have to measure the end object distance from neutral element by creating the refernce line in a sketch at center or measuring the whole length and divide into half.

Y value is 432mm.

We use the maximum moment of inertia because it should be farthest from the neutral axis.

`S = (4.47*10^6)/432`

S = 10347 `mm^3`

SECTION MODULUS FOR MODIFIED SECTION:

I had increased the depth between the hood outer panel and the inner panel from 20mm to 25mm and it differ from previous section as follows,

The calculated section modulus value for the new section is

moment of inertia(max):4.49*10^6

moment of inertia(min):2.31*10^4

The section modulus is

`S = (4.49*10^6)/432`

S= 10394 `mm^3`

CONCLUSION:

It is evident from the calculated data that the section modulus is increasing by modifying the section of a component.Thus section modulus has been analysed for the hood assembly.