Section Modulus calculation and optimization
SECTION MODULUS CALCULATION AND OPTIMIZATION
Aim
To calculate the section modulus for my previous hood design and optimization of hood.
Section modulus
Section modulus 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 gyraion for compression, and moment of inertia and polar moment of inertia for stiiffness. any relationship between thsese properties is highly depend on the shape in question. Equation of the section modulii of common shapes.
These are two types of section modulii the elastic section modulus and plastic section modulus.
Formula for section modulus
S = I / y
Here,
S = Section modulus
I = Moment of Inertia
y = distance from neutral axis to the extreme end
unit mm
Define Elastic sectioon modulus?
The elastic section modulus is defined as S = I / y,
Where
I is the second moment of area (area moment of Inertia)
y is the distance from the neutral axis to any given fibre
Calculation of section modulus
Section 1 :
Section inertia analysis for hood design
Comment used for NX cad
- Datum Plane
- Intersection curve
- Sketch
- Input option for Section Inertia analysis
y is the distance from neutal axis
Moment of Inertia (max) = 8.89 * 10^7 mm^4
Moment of Inertia (min) = 2.6521 * 10^5 mm^4
y = 877.134 / 2
= 438.567 mm
S1 = I / y
2.6521 * 10^5
S1 = 607.7194 mm^3
Section 2 :
Hood design optimization by add the offset value of 0.5 mm or increasing the depth of the inner pane by 0.5mm
l
Moment of Inertia (max) = 1.2 * 10^8 mm^4
Moment of Inertia (min) = 3.7869 * 10^5 mm^4
y = 877.134 / 2
= 438.567 mm
S1 = I / y
2.6521 * 10^5
S2 = 863.4712 mm^3
Conclusion:
So, here difference between the moment of Inertia for section modulus S1 and change the depth of design is S2. S1 is lesser than the S2