Section Modulus calculation and optimization

 SECTION MODULUS

section modulus is a geometric property for a given cross - section used in design of beams or flexural members. it defines the strength of beams which depends upon the cross-section area of that beam.

Though section modulus is generally calculated for the extreme tensile or compressive fibres in a bending beam, compression is often the critical case due to onset of flexural torsional buckling.

formula for calculating section modulus:

S or Z = I/Y

S or Z - section modulus of material.

I = Moment of inertia

Y - length of extreme fibre from the nuetral axis

#Design: Section modulus of initial hood 

calculating section modulus of initial hood

cross-section of hood

sectional report

here the hood shape is asymmetric thre will be two values of setion modulus

so,

Imax = 9.08 * 10^7 mm^4

Imin = 2.91 * 10^5 mm^4

Y = 438 mm

Smax = Imax/Y = 9.08 * 10^7/438 = 207305.936 mm^3

Smin = Imin/Y = 2.91 * 10^5 / 438 = 664.383 mm^3

this is the result of section modulus of initial hood design.

#Design2:section modulus of optimised hood

to improve the value of section modulus we need to optimize our present hood design.

for that purpose, we will offset the outer panel of our hood by 0.5mm to increase the sectional area of our hood and therby increase in section modulus.

Cross-section of improved design

sectional report

here we can take Imin as moment of inertia because it has to be increased ,

like in this case the value of Imin is increased,

Imin = 2.93 * 10^5 mm^4

Y = 438mm

s = I/Y = 2.93*10^5/438 = 668.949mm^4.

hence section modulus of the hood has been inccreased as compared with previous value 

CONCLUSION

hence, from the above study, it is clear that optimisation helps to improve the results in a design as we have increased the section modulus of our hood.