Section Modulus calculation and optimization

Project: Section Modulus Calculation & Optimization

Introduction:

This project report is about Section Modulus Calculation & Optimization of model.

Objective:

The aim of this Project is to calculate section modulus of Hood and optimize the model for strength.

Introduction:

Section Modulus is a geometric property for a given cross-section area used in structural engineering design. There are two types section modulus called Elastic section modulus and Plastic section modulus.

In this report we are discussing about Plastic section modulus.

Plastic Section Modulus Equation:

S=I/y, where

S= Elastic Modulus

I = second moment of sectional area

y= distance from neutral axis to extreme end of the object

For this hood analysis and optimization, we will consider “y” distance as from center to the outer edge of hemmed outer panel.

Importance of section modulus:

It is directly related to strength of part of which section is considered.

It gives an idea about how much load the given structure can bear.

Its easier to calculate strength and bending stresses in structure using section modulus.

Calculation for Section modulus of Hood:

Take a section of hood along the length of the hood.

Use wave geometry linker command to copy the outer line of the section.

Then project the linked geometry on to a sketch plane and create a closed loop sketch.

Use Section Inertia Analysis command to calculates principle moment of inertia, circumference, area and center of gravity of section.

Then we use principle moment of inertia in the formula to calculate section modulus.

Design #1

From command we get,

MOI_max = 8.29 X 10⁵ mm⁴

MOI_min= 4.96 X 10³ mm⁴

y = 243.65 mm

to calculate section modulus,

S_max = 8.29 X 10⁵ mm⁴/243.65 mm = 3402.42 mm³

S_min = 4.96 X 10³ mm⁴/243.65 mm = 20.36 mm³

Design #2

In design 2 I have offeseted the inner panel down by 1mm to increase area of section and calculated principle moment of inertia using section inertia analysis command.

From command we get,

MOI_max = 8.25 X 10⁵ mm⁴

MOI_min= 3.88 X 10³ mm⁴

y = 243.65 mm

to calculate section modulus,

S_max = 8.25 X 10⁵ mm⁴/243.65 mm = 3386.01 mm³

S_min = 5.41 X 10³ mm⁴/243.65 mm = 22.20 mm³

Conclusion:

From above calculation, if we compare the minimum value of section modulus of both the designs, we get to know that by offesetting the inner panel by 1mm in design #2 increases the section modulus of hood by 9.04% than design #1.