Section Modulus calculation and optimization

Section modulus:

• SECTION MODULUS is a geometric property for a given cross-section used in the design of beams or flexural members.
• Other geometric properties used in design include area for tension and shear, radius of gyration for compression, and moment of inertia and polar moment of inertia for stiffness. Any relationship between these properties is highly dependent on the shape in question.
• There are two types of section moduli, the elastic section modulus and the plastic section modulus.

The elastic section modulus is defined as S = I / y, where

S = Section Modulus

I = Moment of Inertia

y = distance between the neutral axis and the extreme end of the object .

PROCEDURE FOLLOWED TO MEASURE SECTION INERTIA IN SIEMENS NX:

• By using the Intersection curve tool on the Hood outer and inner panel part design, an intersection curve is created.
• Closing the intersection curve by adding curves and trimming unwanted curves, to peerform the section inertia analysis.
• Use the section inertia tool to view the result of maximum and minimum moment of inertia values.

SECTION 1:

From the above picture, the minimum moment of inertia value is considered for the Section modulus calculation. Because, the minimum inertia value is the most susceptible for easy breaking of the Hood part.

'Y' distance is with respect to one end of the curve to the center axis of the intersection curve.

Y= 477.5/2 = 238.75 mm

I= 1.337624282 e+05 mm^4

S= I/Y = 1.337624282 e+05 mm^4 / 238.75 mm

S= 560.2614 mm^3.

SECTION 2:

In the section 2, I had modified the outer curve of the inner panel by offsetting the curve to 0.3 mm, in order to check whether the Section modulus increases for the increased offset curve of inner panel outer curve than the actual curve of section1.

Y= 477.5/2 = 238.75 mm;

I= 6.875266124 e+04 mm^4;

S= I/Y = 6.875266124 e+04 / 238.75 = 287.969 mm

S= 287.969 mm^3;

FINAL CONCLUSION: It is hereby concluded from both the Section modulus calculated values that "Section 1" is having the highest strength on the Hood design than the Section2.

Therefore, the Hood design of section1 curve is having higher strength on the part and there is no need to come with different section modulus curve.