Roof challenge

ROOF DESIGN CHALLENGE

AIM -

to design a roof of a car and do the curvature study to resist heat destortion ans snow load condition

AUTOMOTIVE ROOF :-

an automotive roof ar car top is the portion of an automobile that sits above the passsenger co,partment protecting the vehicle ocuupants from sun,wind,rain, and other exernal elemnts

automobile roofs are conventionally suported by pillers on each sides

DESIGN OF AN AUTOMOTIVE ROOF

the first step in designing an automotive roof is to create an outer surface , which are usually design by an stlling team based on parent car desugn and austhetic

Following procedure is follow for designing a roof

• usign surface modelling techniques, necessary ditch areas are designed on all the sides of the roof
• in addition on that ,rails and spoilers, if necessary are designed on all the sides of the roof
• the surface is provided with a 0.75 mm thichness.
• to increase the strenth and join the rof with the body of the car , some reinforcment are provided on the roof. such as,

1- Front roof rail

2-rear roof rail

3- center roof rail

4-Bow roofs

FRONT ROOF RAIL:

Front roof rail is the one which joins the wind shield glass,body side outer and the inner panel also.here the front roof rail is designed baseed up on the master section given.

REAR ROOF RAIL:

Rear roof rail is the one which joins the back door and the body side outer.

CENTER ROOF RAIL.

Central roof rail help in providing efectively support to the flat area of the roof as it is more susceptible to failure under the action of load.

generlly central roof rail is placed at the centre of roof which is connected to b-piller suppport structure . this central roof rail helps in adding the strength to the roof during the roof over test.the thichness of the central roof rail is 1.25mm.

BOW ROOF.

The bow roofs are given to improve the torsiona stiffness ad load bearing capacity of the roof structure.the number of bow roof present is depends on the overall size of the roof. presently in this project tow roofs are added.

JOINNING PROCESS:

mastics are introduced between the roof outer between the roof outer panel and the reincforcement for joinning.

where ever the mastic are introduced there is remarkable improve of the strenght.

spot welding also introduced to join the reinforcement.

DESIGN CONSIDERATION FOR A ROOF:

1-VISIBILITY CRITERIA

2-HEAD CLERANCE

3-CURVATURE STUDY

4-HEAT DISTORTION AND SNOW LOAD CRITERIA.

5-DRAFT ANALYSIS.

HEAT DISTORTION STUDY ON THE ROOF:

The heat distortion study playes a major role in sheet metal usage.heat distortion temperature is a temprature limit above which the material cannot be usede fr the structural applications.this study is used to predict the heat distortion temperature at where the material starts to soften when exposed to a fixed load at relevant temperature. in oreder to avoiding bending or damaged on the roof, based on the heat distortion temperature, this study will predict the bow roof positioned which helps to strenghten the roof.

BOW ROOF PREDICTION FORMULA

W=[1.73X10^(-3)XL]+[1.85X10^(-8)X(R^2)/T]+[1.10X10^(-3)X I]-2.28

where

L=Roof lenght in x-direction [mm](Roof dimention in 0-y)

R=Roof curvature

R=2(Rx*Ry)/(Rx+RY)

Rx= X curvature

Ry = Y curvature

t= Roof plate thickness[mm]

i=bow roof span [mm]

judgment condition: ok<2.7>3.1

where NG not good

SNOW LOAD CRITERIA:-

This evolution is perform in cold regios where snow occurs. roof design must pass throw these calculations tonensure that is sufficient stiffness to withstand the load due to accomalation of snow over the roof.

SNOWED CRITERIA:-

CONCLUSION:-

The sectionmodulus study for master section and create for the front roof rail,rear roof rail,Bow roof rail and rear roof rail and creaton of the ditch area,and to ferform the draft analysis all are sucessfully done using nx.