Section Modulus calculation and optimization

What is Section Modulus?

Section modulus refers to a geometric property of a structural cross-section that gauges its capacity to resist bending. It quantifies how much a beam or structural element can withstand bending stresses.

Mathematically, the section modulus( S ) is determined by dividing the area moment of inertia ( I ) by the maximum distance from the neutral axis ( y ). This relationship is represented as ( S = I/y).

A higher section modulus indicates greater resistance to bending. This parameter holds significance in structural engineering, particularly in the design of beams and columns to ensure they can endure the loads they will encounter in practical applications.

Formula :

S=I/y

S= Section Modulus

I= Area Moment Of Inertia

y= Maximum distance of the hood's outermost part to the Neutral axis

Now Let's Calculate it in NX Cad:

Case 1:

1. Create a datum plane at the center of the Assembly by using the datum plane command and then select on curve option, select the middle line, and give %arc length as 50% as shown below:

2. Create Intersection Curve: click on the intersection curve option, now select the face of the outer panel and then the inner panel in Set 1 as given below: and then select the Datum Plane in Set 2 and click OK Your intersection curve is ready.

3. Now Create Sketch using the Sketch Option and project this Insection Curve in the created Sketch as shown below and then hide the intersection curve.

and now select the studio spline option and create a spline in between the gaps like this:

Select "by poles" and "single segment" and select the starting and the endpoints to close the open sketch.

4. Select the "Section Inertia Analysis" Option and provide the thickness of 0.75 as shown below:

now click OK and we will get the result as :

Now measure the distance between the endpoints of the curve and calculate the section modulus:

Now Let's Calculate Our Case 1 Section Modulus:

S=I/y

I=2.8666852411e+ 05 mm^4

y=876.6 mm

So,

S=2.8666852411e+05/876.6 mm^3

=0.485373 mm^3

Now,

Case 2: Now By Modifying the previous Sketch calculate the new Section Inertia Analysis and calculate the new Section Modulus like this :

Modified Sketch:

Now new Section Inertia Analysis Results: with improved MOI Value

In This Case, Section Modulus (S) = I/y

I=2.90815019e+05 mm^4

y=876.6 mm

So now the new, Section Modulus

S=0.492365682001 mm^3