Section Modulus calculation and optimization

AIM : Use the Section from your Hood design and calculate the section modulus using the formula S = I/y

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 gyration for compression, and moment of inertia and polar moment of inertia 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.

S = I/Y

S = Section Modulus

I = Moment of Inertia

y = distance between the neutral axis and the extreme end of the object

PROCEDURE :

• By using the intersection curve tool on the hood outerand inner panel part design, an intersection curve is created.
• Closing the intersection curve by adding curves and trimming unwanted curves.

SECTION 1 :

The above picture is the minimum moment of inertia value is considered for section modulus calculation.

Section 1

Type : Hollow

CG (-0.000193487, 750.941818100, -930.503880475) [mm]

MOI (Max) : 8.212975461e+05[mm^4]

MOI(Min) : 4.957963898e+03[mm^4]

Principal direction :

Max : (-0.000012365, 0.980748511, 0.195275081)

Min : (0.000001685, -0.195275081, 0.980748511)

section length : 2.034347765e+03[mm]

section area : 40.584316334[mm^2]

Calculation :

Minimum moment of inertia (I) = 4.957963898e+03[mm^4]

Distance from N.A (Y) = 241.053 mm (since 482.1073/2)

hence

section modulus S = I/Y

S = 4.957963898e+03mm^4/241.053

S = 683.54 (mm^3).

Existing cross cross section modulus value is 683.54 (mm^3).

SECTION 2:

Now the design is modified

Type : Hollow

CG (6.1450193487, 750941818100, -930.503880475) [mm]

MOI (Max) : 9.28428821e+05[mm^4]

MOI(Min) : 2.873989373e+03[mm^4]

Principal direction :

Max : (0.000012365, 0.990748511, 0.195275081)

Min : (0.009901685, -0.195275081, 0.980748511)

section length : 3.757811546e+03[mm]

section area : 1.4029871536e+03[mm^2]

Calculation :

Minimum moment of inertia (I) =2.873989373e+03[mm^4]

Distance from N.A (Y) = 241.053 mm (since 482.1073/2)

hence

section modulus S = I/Y

S = 2.873989373e+03[mm^4]/241.053

S = 654.312 (mm^3).

Conclusion : Concluded from the both section modulus created values the section 1 is having highest strength on the hood design than the section 2.

Therfore the hood design of section 1 curve is having higher strength on the part and there is no need to come with different section modulus curve.