Section Modulus calculation and optimization
SECTION MODULUS CALCULATION AND OPTIMIZATION
- Section Modulus is the geometric property of the given cross-section of any shaft or beam structures.
- It is the direct measure of the strength of the shaft section or the beam section.
- Higher the section modulus of a structure, the more the resistive it becomes to bending.
- Mathematically, It is represented as
S = I/Y
I = moment of inertia
Y = Distance from the neutral axis to the extreme edge of the shaft.
- From the above equation we can see that section modulus is directly proportional to inertia which means to have more section modulus or strength we need to have more moment of inertia.
- By using this formula, I am going to calculate section modulus of automotive hood design.
- We are also going to see how we can improve the section modulus of hood.
HOW TO CALCULATE SECTION MODULUS OF ANY COMPONENT (for hood in our case):-
- First, we will create a plane on the middle of the hood using the curve at middle.
- Now take intersection of created plane and hood to get the section view of the component.
- Create a new sketch using same plane we created initially because we need 2-D sketch.
- Now project the intersection curve in this sketch.
- Now, start cleaning the extra line using trim option and try to create a closed curve using studio spline.
- As we get our closed sketch, go to analysis and click on section inertia analysis( feature in NX to calculate inertia). We have to take minimum value of moment of inertia for calculation of section modulus.
CASE 1:-
- From this we can see that min MOI = 1.423342096e+004[mm^4]
And ‘Y’ value = Total length/2 = 875.3303/2 = 437.66515
So, section modulus (S) = I/Y = 1.423342096e+004/437.66515 = 32.521 [mm^3]
CASE 2:- By offsetting the inner panel curve by 1 mm downward to see the effect
- For this section , we can see that min MOI = 1.428934198e+004 [ mm^4]
And ‘Y’ value = Total length/2 = 875.3303/2 = 437.66515
So, section modulus (S) = I/Y = 1.428934198e+004/437.66515 = 32.6494 [mm^3]
We can clearly see that value of section modulus has increased which means strength of hood has increased.
NOTE:-
- For the second case all process is repeated for creating the new sketch.
CONCLUSION
As we can clearly see that by changing the dimension there is increase in moment of inertia and so in the section modulus of hood. So, like this we can increase the strength of our component. This section inertia analysis is done locally to increase the strength locally but for this case we have done for the component.