Section Modulus calculation and optimization

The elastic section modulus is defined as S = I / y, where I is the second moment of area (or area moment of inertia, not to be confused with moment of inertia) and y is the distance from the neutral axis to any given fibre.

S = I/Y

Sectional Modulus is the ratio of moment of inertia and distance between the neutral axis and extreme end.It gives the idea of how much the material is resistant to bend/ deformation. As the moment of inertia increases the sectional modulus increases and hence more is the resistant to the bend.For this emboss were given to reduce the distance between the inner and outer panel, as the distance decreases the sectional modulus increases.

The inertia is increased, which increases the sectional modulus of the hood panel. This makes the hood more resistive towards the bend.Main purpose of this analysis was to get the inertia of the hood and study of sectional modulus and improve it to withstand more loads.

SIGNIFICANCE OF SECTION MODULUS:

• Section modulus is the important factor for design of beam and flexural member design.
• More the section modulus, more the member is resistant to bending of the beam.
• It is easier to calculate stresses in beam and an exact measure of strength of steel.
• If two beams are made of same material and comparing the “section modulus” of two
  beams, the beam with bigger section modulus will be tougher and more capable to
  withstand larger loads.

ROLE OF CROSS SECTION IN SECTION MODULUS:

• Section modulus depends only on the cross section shape of the beam. Cross section shapes like rectangular, square, circular, I section and T, composite section etc.
• For symmetric sections, the value of “section modulus” is for both above and below of centroid of the fiber.
• An asymmetric section has two values for top and bottom of the fiber due to different distance from centroid to the top and bottom of the material, the maximum “section modulus” is S max and the minimum section modulus is S min.

CALCULATIONS

• For the first crossectional

M1(minimum moment of inertia)=4.09e-007m4=4.09`xx``10^-7``xx``10^12`=4.09`xx``10^5`mm4

y=477.349mm

S=`4.09`xx``10^5`mm4``-:`477.349mm``=856.815`mm^3`

• For the second crossectional 

M1(minimum moment of inertia)=9.02213e-007m4=9.02213`xx``10^-7``xx``10^12`=9.02213`xx``10^5`mm`

y=477.349mm

S=`9.02213`xx``10^5`mm4``-:`477.349mm``=1890.049`mm^3`

Therefore, a small modification in Sectional area & increasing the distance between the Inner and outer panel of the Hood assembly we got the higher value of section modulusresults to variation of section modulus. This makes the hood more resistive towards the bend.