Section Modulus calculation and optimization
Section Modulus calculation and optimization
- Section modulus is a direct measure of strength of any sectional area of an object about an reference axis(neutral axis).
- Strength is nothing but, capable of supporting greater loads, so higher the strength it has a high capable of supporting greater loads.
- This strength can measured directly from Section modulus formula, and defined by below formula.
- Section modulus represented with a symbol of 'S'.
S=I/Y
Where 'I'moment of inertia,
Y' is the distance from the reference line(neutral axis) to one of the extreme end of an object.
- Moment of inertia is nothing but offering resistance against of moment, bending or twisting, i.e if we applied any external load on the body, how much resistance its offering to tend to deform.
- So, higher the value of moment of inertia , have higher resistance to deform under certain load, hence we can say that moment of inertia directly proportional to the strength of the material , and strength of the material can be calculated with the help of section modulus.
- If we vary the neutral axis towards positive or negative side the overall strength of the body will decrease , because when nuetral axis line lies on the middle of the section only have higher strength at particular point, so, here 'Y' value was inversely proportional to section modulus.
Thats why formula represented as above.
Case 1
For safe design we always consider minimum strength criteria
y/2 = 482.6941/2 mm
y = 241.347 mm
taking Moment of inertia (Min) = 5.8325 * 10^(3)
S= MOI/y
=5.8325*10(3)/241.347
=24.1664 mm^(3)
Case 2
For safe design we always consider minimum strength criteria
y/2 = 482.6941/2 mm
y = 241.347 mm
taking Moment of inertia (Min) = 7.942936 * 10^(3)
S= MOI/y
=7.942936 * 10^(3)/241.347
=32.9108 mm^(3)
As we know section modulus represents the resistance to bending i.e. the strength of the part.
Here we can see in case two where we have modified the section,
moment of inertia is increased so, the section modulus is increased which increases the strength of the component.
The moification is done in the cross sectional area.