Section Modulus calculation and optimization

Section Modulus calculation and optimization of hood

Section modulus-

It is a property for any given crossection use to design a structure. It is a direct measurement of strength, higher the section modulus of the structure, the more it will be resistive to bending while load applied. It is denoted by 'S'.

It is the ratio of the Area moment of inertia 'I' to the distance 'Y' extreme end layer from the neutral axis.

S = I/y

The area moment of inertia is a property of a two-dimensional plane shape which characterizes its deflection under loading. Denoted with I and unit is dimensions of length to the fourth power.

Hood Section Modulus Calculation-

Calculate the section modulus of car hood using Nx cad.

Take a section in the middle of the hood model.

Find the Moment of inertia of it.

Moment of inertia-

MOI (Max)- 4772944.9 mm^4

MOI (Min)- 14924.7 mm^4

Section modulus-

Find the value of Y

Y = 879.5 / 2 = 439.75 mm

S (max) = I (max)/Y

= 4772944.9 / 439.75 = 10853.76 mm^3

S (min) = I(min)/Y

=14924.7/ 439.75 = 33.9 mm^3

Optimization-

Change the structural sketch to increase the Section modulus of it.

Offsetted inner panel outine and added emboss on both sides.

Find the Moment of inertia of it.

Optimized Moment of inertia-

MOI (Max)- 4846873.2 mm^4

MOI (Min)- 16211.5 mm^4

Optimized Section modulus-

Y = 879.5 / 2 = 439.75 mm

S (max) = I (max)/Y

= 4846873.2 / 439.75 = 11021.8 mm^3

S (min) = I(min)/Y

= 16211.5 / 439.75 = 36.8 mm^3

So, by this the section modulus is increased which further increases the strength of the structure.