Section modulus calculation and optimization

AIM:

Determine the movement of inertia of the created hood and optimized hood and compare both.

INTRODUCTION:

Section modules:

• Section modulus is the ratio of bending to the farthest fiber from neutral axis.
• It is used to know strength of beam.
• Its unit is mm3.

Section modulus (S) = I/Y

I – Moment of inertia of structure

Y – Distance between the neutral axis and extreme end of the object

Moment of inertia:

• Inertia means resistance to the force.
• It means quantitative measure of the rotational inertia of a body.
• Moment of inertia is how much amount of beam bending when load applying.
• Its SI unit is kg m².

I = L / ω

I – Moment of inertia

L – Angular momentum

ω – Angular velocity

Types of moment of inertia:

1. Mass moment of inertia
2. Area moment of inertia
3. Angular moment of inertia

We are using area moment of inertia here.

For different shapes:

OUR MODEL:

We have a hood model. We are going to calculate the section modulus for this hood and optimize and calculate again.

METHOLOGY:

PROCESS:

• First create a plane in the centre of hood then and take inter section curve for the hood with respect to this plane. This curve is not fully closed. So, go to sketch.
• Create a sketch in the created plane project the intersection curve and fill the gap by lines. Extend and trim the lines to create a full closed curve.
• Reference lines draw and measure the length of hood.

• Section inertia tool is used to get moment of inertia of the model. It is used to calculate the section of modulus by the formula.

Calculation:

In this case we have got this result

1. Maximum moment of inertia: 4.82763811*10^6mm^4
2. Minimum moment of inertia: 1.490174018*10^4mm^4
3. Hood length: 878.633 mm

We should take minimum value for section modulus calculation.

Section modulus (S) = I/Y

Y= L/2 = 878.633 mm / 2 =

Y = 439.3165 mm

Section modulus = 1.490174018*10^4mm^4 / 439.3165 mm

S = 0.003392*10^4 mm^3

S = 33.92 mm^3

Optimized Hood:

We have offset the projection curve at 0.5mm and calculate the section modulus.

In this case we have got this result:

1. Maximum moment of inertia: 4.817071783*10^6mm^4
2. Minimum moment of inertia: 1.512508720*10^4mm^4
3. Hood length (L): 878.633 mm

We should take minimum value for section modulus calculation.

Section modulus (S) = I/Y

Y= L/2 = 878.633 mm / 2 =

Y = 439.3165 mm

Section modulus =1.512508720*10^4mm^4 / 439.3165 mm

S = 0.0034428*10^4mm^3

S= 34.428mm^3

CONCULATION:

Moment of inertia and section modulus are successfully calculated and compared with optimized model. When we increase the crosses section area of the hood, moment of inertia and section of modulus increased. So, strength also increased. We have concluded that while we offsetting the inner panel at 0.5mm in downside(optimized) we get result better than previous model.