Section Modulus calculation and optimization

OBJECTIVE:

Use the Section from your Hood design and calculate the section modulus using the formula S = I/y

S = Section Modulus

I = Moment of Inertia

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

Come up with a new section that has improved the section modulus of the previous section and mention what change you made that has increased the strength.

ANSWER:

To calculate MOI of the hood ,

Step1: Import the model and use intersection tool to create a section along yz plane .

Step 2: Use multipe extract to create section of outer profile of hood outer panel and inner profile of hood inner panel .

Step3: Use line command to create lines and join the lower mulitple extract into a single curve .

Step4: Create 2 points on the inner hood section and split it with reference to end points of hood outer panel section . Create 2 lines and join them to obtain a closed contour .

Step 5: Use Fill command to obtain a surface within the closed contour

Step 6: Use Measure Inertia option to obtain MOI of the above surface

Here I=M1 = 6.862e-007 m^4 = 6.862e5 mm^4

Step 7: Create a sketch about yz plane and measure distance from end points about vertical axis .

Y= 477.95/2= 238.975

Section Modulus = I/Y = 686200/238.975=2871.43 mm^3

To obtain a higher value of section modulus

Step1 :Use parallel curve to offset the section of hood inner panel to 0.5mm .

Step2: Repeat steps 4 to 6 to obtain a surface.

Step 3: Measure I

Section modulus =I/Y = 721600/238.975= 3019.56 mm^3

Inference :

1)The section modulus increases as the distance from neutral axis increases.

2) Sectional modulus increases as the sectional area increases

3) Embosses can be added to increase the stiffness of the hood (by increasing the sectiona area)