Section Modulus calculation and optimization

Section Modulus for hood design

OBJECTIVE :

• To caluculate the section modulus of hood design
• To upcome with some new changes that has new section modulus

Section modulus :

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

SECTION MODULUS (S): I/Y(MAX)

I= AREA MOMENT OF INERTIA OR SECOND ORDER MOMENT OF INERTIA.

Y(MAX)= DISTANCE OF EXTREME LAYER FROM NEUTRAL AXIS.

Alternatively, it can also be defined by the below formula

M/I = σ/Y

M = σ*S

σ= YIELD STRENGTH

S= SECTION MODULUS

Mastersection for hood design :

The following are few iterations performed over the ENGINE HOOD cross-section.

1. Inner and Outer panel with 2mm offset as per the actual master section

I(MAX): 4.823 X 10^6 mm^4; Y:440.6 mm

S=I/Y= 10946 mm^3

• Modified changes in with changes in section modulus

I(MAX): 4.838 X 10^6 mm^4; Y:440.6 mm

S=I/Y= 10980 mm^3

• Inner and Outer panel with 4mm offset. No geometry changes.

I(MAX): 4.873 X 10^6 mm^4; Y:440.6 mm

S=I/Y= 11059 mm^3

• Inner and Outer panel with 5mm offset. No geometry changes.

CONCLUSION : Different sections, as shown above, were tried in order to achieve a higher moment of inertia. It is observed that increasing the gap between the inner and outer panels has resulted in decreasing bending moments. No significant change in section modulus is observed just by increasing the gap between the panels. On the contrary, if we tend to add more geometric features to the master section resulted in a drastic increase in section modulus. Hence it is best to add more geometric features to the master section to improve the stiffness of a section. However, this could result in an increase in manufacturing cost