Section Modulus calculation and optimization

AIM:

To Determine the section modulus using the formula S = I/y for hood design and to develop a new section which improves the section modulus of the previous section.recording the change in the hood design structure.

Formula:

S = I / Y ;

I = Moment of Inertia.

Y = Distance between the neutral axis an the extreme end of the object.

S = section modulus.

Section Modulus:

• Ratio of total moment resisted by the secion to the stress in the extreme fibre.
• It gives us an Idea about how much of load the given structure can take.
• If the section modulus increases the moment of resistance and hence its load bearing capacity.

Creating master section for hood design by using the intersection command. The intersection is done along the xy plane through hood model. so for creating a xy plane.

Intersection command:

intersection line will appear as master section.

join the inner panel and outer pannel of the hood.

after join use fill command to create section surface.

using moment of inertia 2d command.

after getting the moment of inertia max and moment of inertia max which are;

Imin=m1=2.356e^-006 m^4;

Imax=m2=9.243e^-004 m^4;

let us consider minimum moment of inertia first.

the distance between the neutral axis and the extreme end of object is known as Y in the section modulus formula.

so total distance divided by 2.

So y = 879.407/2:

y=439.7035 mm.

the section modulus for max and min moment of inertia is

Smin=Imin/y= 2.356e^-006 m^4 / 439.7035 mm = 5358.137 mm^3;

Smax=Imax/y=9.243e^-004 m^4 / 439.7035 mm = 2.102*10^6 mm^3;

Smin=5358.137 mm^3.

Smax=2.102*10^6 mm^3.

To develop a new section which improves the section modulus of the previous section by changing the area of section modulus. Increase section modulus will increase the load carrying capacity of the hood.

again joining the increased section modulus and fill the closed section modulus using fill command.

to find out the moment of inertia of the section.

so total distance divided by 2.

So y = 879.438/2:

y=439.719 mm.

the section modulus for max and min moment of inertia is

Smin=Imin/y= 2.464e^-006 m^4 / 439.719 mm = 5603.578 mm^3;

Smax=Imax/y=9.53e^-004 m^4 / 439.719 mm = 2.167*10^6 mm^3;

Smin=5603.578 mm^3.

Smax=2.167*10^6 mm^3.

conculsion:

• MOI increases with the increase of section area.
• MOI increases with the increase of section length.
• If we increase the gap between the inner and outer panel of hood eventually section length will increase thus MOI will increase.