Section Modulus calculation and optimization

SECTION MODULUS

Section modulus is a geometric property for a given cross-section used in the design of beams or flexural members. Other geometric properties used in design include area for tension and shear, radius of gyration for compression, and moment of inertia and polar moment of inertia for stiffness.

Section Modulus is also referred to as the Polar Modulus or the Torsional Sectional

Section modulus is defined as the ratio of moment of inertia to the radius of the shaft or the distance from the neutral axis to the outer fibres

S = I/y

Where,

S = Section Modulus

I = Moment of Inertia

y = distance between the neutral axis and the extreme end of the object

Section Modulus calculation on Hood Design

Here Y is the neutral axis between two extreme points.Thus the total length /2

where Y=880.1/2

Y=440.05mm

Case 1:Before Optimization

MOI (max) = 4.859465572e+07 (mm^4)

MOI (min) = 1.328968565e+05 (mm^4)

As per the section modulus equation,

S = I/Y

I = MOI (min) value is considered

Y = Total distance /2,

Total distance =880.1mm

Y = 880.1 / 2

= 440.05 mm

Therefore, S1

= 132896.8565 mm^4/440.05 mm

S1 = 302.009mm^3

Optimization

For optimization we offset the inner pannel to 0.5mm downwards for better results

Case 2:After Optimization

MOI (max) = 4.850401659e+07 (mm^4)

MOI (min) = 1.353325124e+05 (mm^4)

As per the section modulus equation,

S = I/Y

I = MOI (min) value is considered

Y=440.05mm

Therefore, S2 = 135332.5124 mm^4/440.05 mm

S2 = 307.538mm^3

SECTION MODULUS CALCULATION AND COMPARISION

SI NO	CASE	MOI(MIN) (mm 4)	DISTANCE (mm)	SECTION MODULUS (mm 3)
1	CASE1	1.328968565	440.05	302.009
2	CASE 2	1.353325124	440.05	307.538

Conclusion:

when comparing case 1 & case 2,

1. The section modulus value of case 2 is higher than the case 1
2. As we increase the section area, the moment of inertia & section modulus increases which means strength and load material also increase