Section Modulus calculation and optimization
Objective:
To find the section modulus of the hood and optimisation to improve the overall section modulus.
what is Section modulus??
is a geometric property for a given cross-section used in the design of beams or flexural members. Other geometric properties used in design include area for tension and shear, Radius of gyaration for compression, and Second moment and polar second moment of area for stiffness. Any relationship between these properties is highly dependent on the shape in question. Equations for the section moduli of common shapes are given below. There are two types of section moduli, the elastic section modulus and the plastic section modulus. The section moduli of different profiles can also be found as numerical values for common profiles in tables listing properties of such.
Neutral axis: The Axis when beam is subjected to pure bending the top most fibres of the beam are subjected to maximum compression, while the bottom most fibres of the beams are subjected to maximum tension
CASE 1: Before Optimization
The Hood which was already created is imported and the section inertia analysis is done.
We have to make sure that the curve obtained is a single/closed curve
Why should We consider Model as hollow??
Eventhough model is solid we consider that as Hallow because, there is gap(0.4mm) between inner and outer panel and iit has joined though Hemming process also one of the reason for this.
MOI (max) = 4.78929532e+06 (mm^4)
MOI (min) = 1.421585725e+04 (mm^4)
As per the section modulus equation,
S = I/Y
I = MOI (min) value is considered
Y = Total distance /2, Total distance =875.5680mm
Y = 878.9 / 2
= 439.45 mm
Therefore, S = 14215.8575 mm^4/439.45 mm
S = 32.35 mm^3
Case 2:The hood inner panel’s curve is offset by 0.5mm outwards and section inertia analysis is done same as case 1 for a closed curve.
MOI (max) = 4.78929532e+06 (mm^4)
MOI (min) = 1.44081973e+04 (mm^4)
As per the section modulus equation,
S = I/Y
I = MOI (min) value is considered
Y = Total distance /2, Total distance =875.5680mm
Y = 878.9 / 2
= 439.45 mm
Therefore, S = 14408.1973 mm^4/439.45 mm
S = 32.7868mm^3
Conclusion:
Hence when comparing case 1 & case 2,
1. The section modulus value of case 2 is higher than the case 1
2. As we increase the section area, the moment of inertia & section modulus increases which means strength and load Material also increase