Section Modulus calculation and optimization
Aim - To increase the section modulus of a hood by making necessary changes
Tool Used - NX CAD
Introduction - 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 gyration for compression, and moment of inertia and polar moment of inertia for stiffness. Any relationship between these properties is highly dependent on the shape in question. Equations for the section moduli of common shapes are given below.
Z = I/Y
Z = Section modulus
I = Area moment of inertia
Y = Distance from neutral axis to the outer most fiber of a material
Area moment of inertia - It signifies the tendency of cross section to resist bending. Greater its value greater is its tendency to resist bending. It is given by - 
Elastic section modulus - The elastic section modulus is used in the design application of structural member which determines the resistance to bending as within elastic limit as per the stress-strain curve. The failure of the component is considered in the elastic region.
So to keep our design values within elastic limits we will use minimum value of moment of inertia because from here itself material will start to deform.
EXISTING HOOD SECTION-
Results obtained are as followa-
I (min) = 1.39e+04 mm4
A = 72.906 mm2
Y = 41 mm
From bending equation: σ/Y=M/I=E/R
S= I/Y
Where,
S - section modulus
I - mimimum principle moment of inertia
Y - distance of the outer most fibre from neutral axis.
So by pluging in these values
S = 1.38e+04 / 41 = 329.02 mm3
MODIFIED SECTION- By incorporating more embosses and increasing in area can increase our moment of inertia because according to formula of moment of inertia more the distance of area from neutral axis greater will be its inertia so keeping that thing
Results-
I min= 1.68e+04 mm4
A =76.301 mm2
Y = 41 mm
S = I/Y = 1.68e+04 /41 = 409.75 mm3
FINAL RESULT - Thus stiffness of the car hood has been increased by increasing its moment of inertia.