Section Modulus calculation and optimization
Section Modulus
Section modulus is the direct measure of the strength of the steel. Bending a steel section that has a larger section modulus than another will be stronger and harder to bend. Section modulus is a geometric property for a given cross-section used in the design of flexural members. There are two types of section moduli, the elastic section modulus (S) and the plastic section modulus (Z). In the case for bending a steel section it is important to calculate ‘S’ by taking the moment of inertia of the area of the cross section of a structural member – divided by the distance from the neutral axis to the furthest point of the steel section. This is where the steel will bend first. The bending moment that it takes to yield that section equals the section modulus times the yield strength.
For general designs, the elastic section modulus is used, applying up to the yield point for most metals and other common materials.
Objective
Calculation and optimization of the section modulus of the hood design.
Section modulus Calculation
- Section modulus of Hood design (Before Optimization)
We have
MOI(Min) = 7.032891578e+03[mm^4]
Y = (486.2438/2) = 243.1219 mm
As per the section Modulus Equation,
S=I/y
MOI(Min) value is considered for I
Therefore,
S= (7.032891578e+03)/ 243.1219
=28.92742932 mm^3
2. Section modulus of Hood design (After optimization)
For optimization of Hood design, I have given 0.5 mm offset to the inner panel curve and also reduce the cut-out distance to increase the section area of the hood
We have,
MOI(Min) = 7.644673755e+03[mm^4]
Y = (486.2438/2) = 243.1219 mm
As per the section Modulus Equation,
S=I/y
S= (7.644673755e+03)/ 243.1219
=31.44378912 mm^3
From the above result we found that That is area of section is directly proportional to section modulus.
Conclusion
The section modulus of front Hood design is calculated and compared with the new optimized design. From the above calculations we found out that increasing the cross-section area results in increase in the section modulus and also increase the strength of the hood.