Section Modulus calculation and optimization for Hood

Section Modulus of Hood

Section modulus is the geometric property of a cross section of a part. It directly represents the strength of a part at the selected cross section It is the ratio of the area moment of inertia and the span from neutral axis to the farthest point of the part. Its unit is mm^3.

Formula: S=I/y

S-Section modulus

I-area moment of inertia

y- distance between central axis to farthest point

using the above formula, the section inertia analysis was carried out for the Hood along the X-direction at the center plane as the cross section.

Two ways of increasing S value is increasing the Area Moment of Inertia value and decreasing the y distance

Original Hood design:

Figure 1

The above fiure shows the least moment of inertia value as 125756.14mm^4.

The S value calculated was 525.40 mm^3 with a y value of 240mm

Modified Hood design:

Figure 2

The above figure shows a modified design of the hood with an inversed emboss at the center region, drawn downwards thus increasing the area and the moment of inertia to a value of 164968.67 mm^4.

Other ways of increasing I value include increasing offset distance between inner and outer panel by an appropriate value.

With the above increased moment of inertia and the same span of 240mm, the section modulus is increased to 689.23 mm^3.

Thus, the increased section modulus shows an increase in strength of the hood and more resistance to bending.

Figure 3: Y span= 478.70/2

Note: An excel sheet representing the calculations is attached with this word document.