Section Modulus calculation and optimization
Section Modulus:
It is a geometric property for a given cross-section used in the design of beams or flexural members. Other geometric properties used in design include area for tension and shear, radius of gyration for compression, and moment of inertia and polar moment of inertia for stiffness.
I have used CATIA V5 to calculate the section modulus. It can calculated in NX CAD as well.
First of all we have to create an intersection with respect to a plane. The pane must intersecting through mid of your part or body. Because the center of gravity is generally found at the center of the part.
There is a tool called "Measure Inertia" in CATIAV5. I have used that tool to find out the moment of inertia of my part.
I took an intersection of my part with respect to the mid plane. I closed that intersection with the help of outer boundaries.
I joined all the lines and used "Fill" command to convert it into a surface.
I opened measure inertia and used 2D object and selected my surface. It showed me my MOI.
Further, Section of mudulus is found my dividing the moment of inertia with the distance between the neutral axis and the extremes of the part.
I calculated my distance.
Thus we can find thesection modulus.
The example is shown below.
S = Section Modulus
I = Moment of Inertia
Y = distance between the nuteral axis and the extreme end of the object
for Initial Hood design
For initial hood design:
Max MOI M1=7.21565* 10^5 MM^4
Min MOI M2= 1.50213 *10^8 MM^4
SECTION MODULUS
S=I/Y
We take Max MOI,
S= 7.21565* 10^5 /490.948
=1.4697 *10^3 mm^3
=1469.7 mm^3
Let us do some modifications to check whether our design can have an improved section modulus.
I have incresed the distance between two panels to check.
The amount is 2.5mm.
After Hood design Modifications:
Max MOI M1= 9.2275 *10^5 mm^4
Min MOI M2=1.76942*10^8 mm^4
Here,
Section Modulus
S=M/Y
= M1/Y
=9.2275 *10^5 /490.948
=1.8795*10^3 mm^3
=1879.5 mm^3
Thus by increasing the distance between the Inner and outer panel of the Hood assembly we got the higher value of section modulus. So by that we can say that the strengh of the part is also increased.