Section modulus

Section modulus is a geometric property of the cross section used for designing beams and flexural members. It does not represent anything physically .

To define section modulus, it may be defined as the ratio of total moment resisted by the section to the stress in the extreme fibre which is equal to yield stress.

S=I/y

S= section modulus

I= moment of inertia

y= distance from nutral axis

Section 1:

I= 4866544.344 mm^4

y= 460.5 mm

S= 4866544.344 / 460.5

S=10567.9 mm^3

Section 2:

I= 5658248.43 mm^4

y= 460.5 mm

S= 5658248.43 / 460.5

S= 12287.18 mm^3

Section 3:

I= 4032524.97 mm^4

y= 460.5 mm

S= 4032524.97 / 460.5

S= 8756.84 mm^3

conclustions:

1.As the section area decreases MOI also decreases.

2.As gap between the upper and lover panel increases MOI increases.