Section Modulus calculation and optimization

Aim:

To calculate the section modulus of the previously designed hood for analyzing its strength and also optimizing the design to see the difference in the bending strength of the hood. Higher the section modulus of a structure, the more the resistive it becomes to bending.

Section modulus:

Section modulus is a geometric property for a given cross-section used in the design of beams or flexural members, it is also referred to as the Polar Modulus or the Torsional Sectional Modulus. 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. There are two types of section moduli, the elastic section modulus and the plastic section modulus.

S=I/Y

Here,

S = Section modulus

I= Moment of Inertia (Unit mm 4)

Y= Distance from Neutral axis to the extreme end (unit mm)

The Unit of a “section modulus” is (mm3)

Moment of inertia:

Here we are considering the area moment of inertia also known as the second moment of inertia. it is used in a sectional mechanical application, usually involving a section of any structure. the shape of the object and the plane of the section will give us the 2d part it is called the section.

When the area of the section increases the moment of inertia also increases. so the final result which is the section modulus also increases.so we could say section modulus is proportional to the moment of inertia.

Objective:

To find a section modulus of the hood, and optimizing the section modulus value using NX_cad.

Section Modulus Calculation 1:

Maximum moment of inertia = 9.086538589x10^7 [mm^4]

Minimum moment of inertia = 2.545046743x10^5 [mm^4]

The total distance of the hood Y = 877.0064 mm

Distance between the neutral axis to the extreme end = (877.0064/2) =438.5032 mm

To find section modulus of HOOD section, we have to calculate

Smax=Imax/Y

Smax=9.086538589x10^7/438.5032

Smax=2.072171x10^7 mm^3

Smin=Imin/y

Smin= 2.545046743x10^5/438.5032

Smin=5.803941x10^5 mm^3

Section Modulus Calculation 2:

Maximum moment of inertia =9.080584022x10^7[mm^4]

Minimum moment of inertia =2.716637327x10^5[mm^4]

The total distance of the hood Y = 877.0064 mm

Distance between the neutral axis to the extreme end = (877.0064/2) =438.5032 mm

To find section modulus of HOOD section, we have to calculate

Smax=Imax/Y

Smax=9.080584022x10^7/438.5032

Smax=2.070813x10^7 mm^3

Smin=Imin/y

Smin=2.716637327x10^5/438.5032

Smin=6.195250x10^5 mm^3

Conclusion:

Section Modulus of Hood of the car was calculated and optimized section modulus with some changes or optimization and found some better results.