Section Modulus calculation and optimization
OBJECTIVE:
The main objective of this project is to understand and learn the basic tools and advanced tools used in NX and calculation as well as section modulus and optimization of Car hood.
SECTIN MODULES:
Section modulus is a geometric property for a given cross-section used in the design of beams or flexural members. It is the ratio of bending to the farthest fiber from neutral axis, or it is the measure of the strength of the part.Other geometric properties used in the design include an area for tension and shear, the radius of gyration for compression, and moment of inertia and polar moment of inertia for stiffness.
Area moment of Inertia:
The area moment of inertia of a beams cross sectional area measures the beam ability to resist bending. The larger the moment of inertia less will be the bend.
Where,
M = Bending moment
I = Area moment of Inertia
E = Youngs modulus
R = Radius of gyration
Neutral axis: When part is subjected to pure bending the top most fibres of the beam are subjected to maximum compression, while the bottom most fibres of the beams are subjected to maximum tension.
Material Data: Stainless steel AISI 302 – cold rolled
Where yield strength of stainless steel is 520MPa = 520 N/mm^2
Use the Section from your Hood design and calculate the section modulus using the formula S = I/y
S = Section Modulus
I = Moment of Inertia
y = distance between the neutral axis and the extreme end of the object
Come up with a new section that has improved the section modulus of the previous section and mention what change you made that has increased the strength.
Section Modulus calculation and optimization
CASE 1: Before Optimization
Maximum moment of inertia = 8.22435547e+05[mm^4]
Minimum moment of inertia = 5.342644867e+03[mm^4] = 5342.644[mm^4]
The total distance of the hood Y = 487.1232
Distance between the neutral axis to the extreme end = (487.1232/2) =243.5616 mm
To find section modulus of HOOD section, we have to calculate
S= 5342.644/243.5616
= 21.93 mm^3
CASE 2: After optimization
Maximum moment of inertia = 8.271595628e+05[mm^4]
Minimum moment of inertia = 7.22911465e+03[mm^4] = 7229.114[mm^4]
The total distance of the hood Y = 487.1232
Distance between the neutral axis to the extreme end = (487.1232/2) =243.5616 mm
To find section modulus of HOOD section, we have to calculate
S= 7229.114/243.5616
= 29.68 mm^3
Conclusion:
Hence when comparing case 1 & case 2,
1. The section modulus value of case 2 is higher than the case 1
2. As we increase the section area, the moment of inertia increases & section modulus increases which means strength also increases.