Section Modulus calculation and optimization

Section Modulus - calculation and optimization

What is Section Modulus?

• Section Modulus can be defined as the ratio of the total moment resisted by the section to the stress in the extreme fiber.
• It gives us an approximate idea of the structure, about how much load it can take.
• if the section modulus increases then the moment of resistance will also increase accordingly, and hence its load-bearing capacity.

How is the Section Modulus calculated?

• First, we take the section of the hood in NX along the X-Axis.
• Then obtain a closed sketch by connecting the curve from anywhere it has a discontinuation, using lines.
• Now, Using the analysis tool Section Inertia Analysis, we can get the inertia details for the section.
• Second, we need y i.e distance from the outer fiber to the center of the hood
• after we complete the above steps, we use the following formula to calculate Section Modulus:

Section Modulus => S = I/y.

where, S = Section Modulus

I = Moment of Inertia (min)

y = Distance from the neutral axis to the outer fiber

So Using the above Formula we will calculate the Section Modulus of the Hood we created using NX

Hood Used to Calculate the Section Modulus:

Section of the above hood:

PART I: (Original)

We Consider the min MOI from the following as the chances of failure is at the minimum area of the component, more comparatively than that of the maximum.

Following are the Values Recorded.

We have,

I = 1.525827364e+04 `mm^4`,

Let's Find y,

y = 878.642/2 = 439.321 mm

Now, for Section Modulus,

S = I/y.

= 1.525827364e+04 `mm^4` / 439.321`mm`

S = 34.7871 `mm^3`

PART I: (Optimized)

For Optimization that is Increasing the strength we generally increase the moment of resistance by simply Increasing the Area of the section. This can be obtained by Offsetting the bottom curve of the section to a certain value. Now as we Increase the area our MOI will also be increased which will result in an increased Section Modulus.

Following are the Values Recorded after Optimizing the section.

We have,

I = 1.554025974e+04 `mm^4`,

Let's Find y,

y = 878.642/2 = 439.321 mm

Now, for Section Modulus,

S = I/y.

= 1.554025974e+04 `mm^4` / 439.321`mm`

S = 35.3734`mm^3`

Conclusion:

The Conclusion is that the Section Modulus can be increased by increasing the total area of the section. So to increase the strength of the Hood we can do it by Increasing the area of the Hood, which will increase the Section Modulus thus increasing the strength.