Section Modulus calculation and optimization

Objective:-Use the Section from your Hood design and calculate the Section Modulus using the formula

S = I/y

Where,

S = Section Modulus

I = Moment of Inertia

y = distance between the neutral axis and the extreme end of the object.

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.

There are two types of section modulus:-

01) Elastic section modulus:- The elastic section modulus is defined as the ratio of the second moment of area (or moment of inertia) and the distance from the neutral axis to any given (or extreme) fiber. It can also be defined in terms of the first moment of area.

02) Plastic Section Modulus:- The plastic section modulus is the sum of the areas of the cross section on each side of the PNA (which may or may not be equal) multiplied by the distance from the local centroids of the two areas to the PNA: The Plastic Section Modulus is not the 'First moment of area'.

• For general design, elastic section modulus is used, applying up to the yield point for most metal and other common material. It is notify by 'S'.

  S = I/y

  Where,

  S = Section Modulus

  I = Moment of Inertia

  y = distance between the neutral axis and the extreme end of the object.

• Moment Of Inertia:-Moment of inertia is defined as the quantity expressed by the body resisting angular acceleration which is the sum of the product of the mass of every particle with its square of a distance from the axis of rotation.

Procedure:- In the hood design case we use elastic section modulus. It prepared as below-

Take assembly product of hood and generate CATPart from product from tool option in catia. then take outer panel and inner panel, then create section geometry of the outer panel and inner panel, later using measure the inertia option and noted it. This value are notify by 'I' and then processed with the calculation to measure the allowable stength of the section.

Section-1

I( Moment of Inertia)= 2.39 e+006mm^4=2390000mm^4

Y(distance between the neutral axis and the extreme end of the object)=441.829mm

S = I/y=2390000mm^4/441.829mm= 5409.332mm^3.

Section-2

To Increase the strength of the above section, i increased 3mm the distance between the outer panel geometry to inner panel geometry then repeated the above said procedures then we have got much better strength value.

I( Moment of Inertia)= 3.02e+006^6=3020000(loxG Value from above image).

Y(distance between the neutral axis and the extreme end of the object)=441.829mm

S = I/y=3020000mm^4/441.829mm= 6835.223mm^3.

Conclusion:-Thus by increasing the distance between inner panel and outer panel of the hood assembly we got the higher value of section modulus hence the strength also increased.