Section Modulus calculation and optimization

AIM : Section Modulus calculation and optimization of HOOD design.

SECTION MODULUS (S)

• Section Modulus is a geometrical property for a given crossection used in the designing of beam of flexural members.
• Easier to calculate the strength and stresses in beam.
• if the beams having same material, then section modulus of two beams are being compared and vice versa. ie, the beam with larger section modulus will be tougher and more load carrying capability.
• It also termed as ratio of second moment of area and the distance from nuetral axis to nuetral fiber.

S = I/Y

where I - moment of inertia , Y - distance from nuetral axis to Top/Bottom of fiber

• more section modulus means member will be more resistant to bending of beam.

SECTION MODULUS Analysis

• Create Datum plane and use Intersection curve
• convert 3D sketch to 2D (by creating sketch)
• Apply section Inertia

Moment of inertia (Max) = 4.96854117*10^6 (mm^4)

Moment of inertia (Min) = 1.65016708*10^4 (mm^4)

H = 883.78mm

Y = H/2 = 883.78/2 = 441.89mm

so, S=I/Y = (4.96854117*10^6) / (441.89) = 11.24 * 10^3 (mm^3) - maximum

& S=I/Y = (1.65016708*10^4) / (441.89) = 37.3 (mm^3) - minimum

2. Optimised Hood Section Modulus Calculation

• offset inner panel by 0.5mm

Moment of inertia (Max) = 4.959784803*10^6 (mm^4)

Moment of inertia (Min) = 1.681632611*10^4 (mm^4)

Y = 441.89 mm

now

S=I/Y = (4.959784803*10^6) / (441.89) = 11.22 * 10^3 (mm^3) - maximum

& S=I/Y = (1.681632611*10^4) / (441.89) = 38.05 (mm^3) - minimum

CONCLUSION

from above calculation of section modulus of before and after optimization of Hood design. we conclude that section modulus is directly proportional to moment of inertia. ie, if we increase moment of inertia then section of modulus also increases. so, we can increase the section modulus just increasing the gap between the outer and inner panel.