Section Modulus calculation and optimization

SECTION MODULUS & OPTIMIZATION

• Section Modulus is the geometric property of any given cross-sectional area of a structure. It is the direct measure of the strength of the structure. Higher the section modulus of the structure, the more the resistive it become to bending.
• In simple words, section modulus is defined as the geometric strength capacity of a structure after applying load upon it.

The section modulus is classified into 2 types: -

1. Elastic section modulus.

The Elastic section modulus is applicable up to the yield point of material.

2. Plastic section modulus.

The plastic section modulus is generally used for materials where the plastic behavior is observed.

Equation for the Section Modulus: -

Section Modulus: S=I/Y.

Where,

I = Moment of Inertia, &

Y = Distance between neutral axis & outermost edge of the structure or geometry.

The SI unit of the section modulus is, M^3.

What is moment of Inertia: -

It is the resistance offered against of moment, bending or twisting i.e., if we applied any external load on the body, how much resistance its offering to tend to deform.

SECTION MODULUS CALCULATION OF CAR HOOD

• Case - 1 Before Optimization:

Here,

I = Moment of Inertia.

Y = Total distance/2.

I(max.) = 8.385773299e+05[mm^4].

= 838577.329905[mm^4]. {On multiplying the value of I(max) by 100000}

I(min.) = 9.867676953e+03[mm^4].

= 986767.695303[mm^4]. {On multiplying the value of I(max) by 100000}

Y(total distance) = 486.9474mm/2.

Y(total distance) = 243.4737mm.

On putting the values in section modulus formula,

S = I/Y

S(max.) = 838577.329905/243.4737.

= 3444.2129mm^3.

S(min.) = 986767.695303/243.4737.

= 4052.8718mm^3.

• Case - 2 After Optimization:

Here,

I = Moment of Inertia.

Y = Total distance/2.

I(max.) = 8.372353539e+05[mm^4].

= 837235.353905[mm^4]. {On multiplying the value of I(max) by 100000}

I(min.) = 9.893007414e+03[mm^4].

= 989300.7414[mm^4]. {On multiplying the value of I(max) by 100000}

Y(total distance) = 486.9474mm/2.

Y(total distance) = 243.4737mm.

On putting the values in section modulus formula,

S = I/Y

S(max.) = 837235.353905/243.4737.

= 3438.7096mm^3.

S(min.) = 989300.7414/243.4737.

= 4063.275mm^3.

CONCLUSION

From above optimizations we conclude that the greater the value of S(min.) the greater the strength of the geometry will be.

If the value of S(min) increases after changing the hood geometry the more stiffer it will become & vice versa.

So. always add some necessary embosses to the inner panel & make the hood more stiffer & shock absorber.