Section Modulus calculation and optimization

Section Modulus Calculation And Optimization

Aim:

To calculate the section modulus of the previously designed hood for analysing its strength and then optimizing the design to increase the section modulus ultimately increasing the strength of the hood.

Section Modulus:

• Section modulus is a geometric property for a given cross-section used in the design of beams or flexural members.
• It is also referred to as the Polar Modulus or the Torsional Sectionlal Modulus.
• There are two types of Section Moduli; the elastic section modulus and the plastic section modulus.

Here, we are going to use elastic section modulus which can be calculated by using the given formula:

• S = I / Y where,
• S = Section Modulus
• I = Moment Of Inertia
• Y = Distance between the netural axis and the extreme end of the object

Calculating the Section Modulus for the Default design:

The section was obtained using intersection curve on the OY axis, closing the open contour, then Section Inertia Analysis was done. The result is as shown in the figure:

Here,

Moment of inertia (Max) = 8.1931 x 10^5 mm^4

Moment of Inertia (Min) = 5.3307 x 10^3 mm^4

Y = 478.4/2 = 239.2mm (from the figure below)

Therefore, Section Modulus (S) = 22..29 mm^3

Optimization for the Hood Design:

For optimizaton, I have offseted my default section by 0.5mm of the inner panel. The following figure is the Secton Inertia Analysis for this modified section:

Here,

Moment Of Inertia (Max) = 8.1739 x 10^5 mm^4

Moment Of Inertia (Min) = 5.5374 x 10^3 mm^4

Y = 239.2 mm

Therefore, Section Modulus (S) = 23.15 mm^3

Conclusion:

Since, the section modulus of the modified(optimized) section is greater than that of the default section, hence the strength of the optimized secition is more.