Section Modulus calculation and optimization

SECTION MODULUS

It is the ratio of area moment of inertia about the neutral axis and to the distance of outermost fibre from the neutral axis.

Section modulus is the direct Measure of Strength of a beam. Higher the Section Modulus higher will be the Resistance to Bending.

The ratio of the steel's bending moment to bending stress is known as the section modulus. A high section modulus steel can tolerate a high moment without undergoing significant bending stress, making it more difficult to bend. To find the bending stress and determine whether the steel can withstand that much moment, divide the maximum bending moment by the section modulus. Next, compare the bending stress to the permissible tensile stress. Every piece of bending machinery has a section modulus rating.

CASE 1 (HOOD DESIGN WITHOUT ANY CHANGES)

DATAS

I = 2.911 X 10^5 mm^4

y = 439.713 mm

FORMULA

Z = I/y

CALCULATION

Z = 2.911 X 10^5/439.713

The section modulus, Z = 662.022 mm^3

CASE 2 ( OFFSETED LOWER CURVE TO 0.75 MM AND ADDING PROJECTION OF RADIUS 10 mm AT THE ENDS)

DATAS

I = 3.0783 X 10^5 mm^4

y = 439.713 mm

FORMULA

Z = I/y

CALCULATION

Z = 3.0783 X 10^5/439.713

The section modulus, Z = 700.07 mm^3

RESULT

CASE 1 , Z = 662.022 mm^3

CASE 2 , Z = 700.07 mm^3

From the result we can see that in case 2, increasing the offset value and providing a projection has significant difference compared to case 1 ,so we can conclude that case 2 has better strenth and load carrying capacity. Increasing the section area leads to increasing in moment of inertia and section modulus of the hood.