Section Modulus calculation and optimization
SECTION MODULUS CALCULATION AND OPTIMIZATION
OBJECTIVE
To calculate the section modulus of the existing hood design, analysing them and come up with the better design to increase its section modulus and optimization.
SECTION MODULUS CALCULATION AND REASON
Section modulus is the calculation of the area and its properties of solid and hollow structures to study or measure its strength to know the resistance of the structure to the bends or any external force which can collapse its physical properties.
Section modulus can be studied for any closed structures to know its strength and it can be improved further for the better resistance property of the design.
SECTION MODULUS STUDY
section modulus formula S = i / y (eqn 1)
‘S’ indicates section modulus
‘I’ is the moment of inertia of the structure
‘Y’ is the distance between neutral axis and end point of the structure
(Moment of inertia is the resistance offered by the material to change its state of rest to motion or deformation unless the external force or stress acts on it)
From the equation 1 we can note that the section modulus is directly proportional to the inertia.
Inertia(I) = L / ω (eqn 2)
L – angular momentum (mass*velocity*radius)
ω – angular velocity
from equation 2 we can notice that inertia is directly proportional to one of its units ‘mass’.
To increase the mass of the object we need to increase its area. So, we can relate this in our design to improve our section modulus.
so, equation 1 and 2 says the section modulus can be varied by changing the area of the body or structure.
So, the section modulus can be increased by increasing the area of structure in our design.
SECTION MODULUS STUDY OF EXISTING DESIGN
The section modulus of the existing design of hood of car in siemens NX software.
MOI (max) I = 4.930642191e+06mm4
Y = 445.5mm the distance between neutral axis and end of the structure
S=i/y= 4930.642191e+03/445.5 = 11.0676592e3mm4
S = 11.0676592e3mm4
The type of metal is stainless steel AISI cold rolled.
Its yield strength Y = 520MPa
Yield moment = S*yield strength
11.0676592e3*520e6 = 5755.18278e9 Nmm
SECTION MODULUS OF MODIFIED DESIGN
The hood design is slightly modified by increasing its area between outer panel and inner panel by reducing the size of the emboss in its existing design.
MOI (max) I = 5.007456996e+06mm4
Y = 445.5mm the distance between neutral axis and end of the structure
S=i/y= 5007.456996e+03/445.5 = 11.240083e3mm4
S = 11.240083e3mm4
The type of metal is stainless steel AISI cold rolled.
Its yield strength Y = 520MPa
Yield moment = S*yield strength
11.240083e3*520e6 = 5844.84318e9 Nmm
The result shows increased section modulus due to increased MOI.
CONCLUSION
The section modulus study for hood design is completed for existing design and the result is noted. Then the section modulus is studied after rebuilding the design and observed the improve in section modulus than the existing one. Therefore the physical strength of the hood is also increased by increasing the section modulus.