SECTION MODULUS OPTIMISATION

SECTION MODULUS

• Section modulus is a geometrical property of a given cross section used in the design of a component.
• It gives us an idea about how much of load the given structure can take.
• If the section modulus increases the moment of resistance increases and hence its load bearing capacity increases.
• Section modulus is calculated by using the formula –

S = I/Y

S is section modulus

I is moment of inertia

Y is distance between the neutral axis and the extreme end of the object.

Unit for section modulus is mm^3

NOTE – Y is distance between the neutral axis and the extreme end of the object. Hence divided by 2.

I = 3.925x10^-7 m^4 Y = 478.127/2 mm

I = 3.925x10^5 mm^4 Y = 239.063 mm

• S = I/Y
• S = 3.925x10^5 mm^4 / 239.063 mm
• S = 1641.8 mm^3

NOTE – Changes made in section are highlighted in red.

I = 3.997x10^-7 m^4 Y = 478.127/2 mm

I = 3.997x10^5 mm^4 Y = 239.063 mm

• S = I/Y
• S = 3.997x10^5 mm^4 / 239.063 mm
• S = 1671.9 mm^3

Hence in case 2 strength increase as the section modulus increases.