Section Modulus calculation and optimization

OBJECTIVE:

To understand and learn the calculation and optimization of section modulus of hood design using the siemens NX CAD

SECTION MODULUS:

Section modulus is named as the extent of the second preview of an area and distance from neutral axis as far as possible fiber.Similarly ,it is thje extent ofthe strenghth of a given part .The pressing factor in the fringe section of the column is figured with the help of the section modulus.It is represented by S

Section modulus has appeared as fallows:

S = I/Y

here Y - is the detachment from theneautral axis to the top or lower part of the fiber .There are 2 sorts of section modulus,the elastic section modulus and the plastic section modulus.The section modulus is of diferent profiles can moreover be found as mathematical characteristics for ordinary profiles in the tables posting properties of such .section modulus is the numerical property of a given cross section used in the design of flexual people . section modulus depends just upon the cross section condition of the bar or development .For symmetric section,the section modulus is like both aobve and under the centriod of the cross section .An Upside -down section has two characteristics for the top and lower parts of the centroid ,the maximum section modulus and minimum section modulus

THYPES OF section modulus:

1 Elastic section modulus:The elastic section modulus is used ,applying up to the yeid point most metals and other fundamental materials

The elastic section modulus is described as S=I/Y ,where I is the second moment of area and y is the distance from the neautal axis to some given fibre .It is consistently declared using y=c,where c is the distance from the neutal axis toa s far as possible fiber.Moreover ,it is consistently used to choose the yeilding moment (My) with the ultimate objective that My=S*@y,where @y is the yeild stengh of the mateerial

Plastic section modulus:

The plastic section modulus is used for materials where elastic yeilding is worthy and plastic behaviour is assumed to be a sufficient beaking point .Design for most part strive to ultimately stay under as far as possible to keep away from intermediate deformations ,often looking at as far as possible against intensified forces or stresses

SIGNIFICANE OF SECTION MODULUS:

• The section modulus of the cross sectional shape is of siginificant importance in designing beams.A beam that has a larger section modulus than another will be stonger and capable of supporting greater loads.
• In case there are two beams having same shape and probably made of same material then how we can decide which to beam should be used .Here we can evalute them by calculating the section modulus of both as the section modulus will provide us the strength of each beam.The beam having more section modulus will carry more load in bending

As we know that

σmax = M*C/Ix = M/Z

Where

M - Bending movement along the length of the beam where the stress is calculated

Ix= moment of inertia about horizonal axis

c is the max distance from the centroidal axis to the extremer fiber

Zx - section modulus

SECTION MODULUS OF THE HOOD COMPONENT:

As the hood is asymmetric there will be two values of section modulus

so

Imax = 1.05 *10^5

I min = 405.676

y = 465

Zmx = 1.05 * 10^5/465 = 225

MODIFIED DESIGN:

To improve this value of section modulus we need to optimize our present hood design

For that purpose ,we will offset the outer panel of our panel of hood by 2mm to increase the section area of our hood and thereby incrrease in section modulus

The reason behind providing offset to the outer panel

As we know that section modulus

S = M Ai^2/y

A - sectional area

from the above equation ,it can be observed that section modulus is dirctly propotional to sectional area of the body,Thats why we increase section modulus by increaing the section areaby offseting the outer surrface and reducing the embossing depth

As the section area will increase momemt of inertia will also increase there by section modulus of hood also increase

I max = 1.07*10^5

y = 465

Z max = 1.07*10^5/465 = 230

Hence the section modulus of our hood has been increased as compared with the previous values which is from 225 to 230