Roof challenge

Roof Design:-

     An automobile roof or car top is the portion of an automobile that sits above the passenger compartment,protecting the vehicle occupants fron sun,Wind,Rain and other external elements.

The Automobile Roof consists of the following parts:-

• The outer panel
• Front roof rail
• Bow roof
• Center roof rail
• Rear roof rail

Front roof rail:-

   Front roof rail is created at the front side of the roof to provide strength to the roof.Headroom clearance and the driver visibility are two important factors to be considered while designing the front roof rail.

Bow roofs:-

   It is used to give strength to the area between the front roof rail and the centre roof rail.Also its created in the area between thw centre roof rail and rear roof rail to provide enough strength.It can created in any number depending upon the roof length but the position of the bow roofs is to be justified by curvature study.

Centre roof rail:-

   Its created at the centre of the roof.It is connected to the roof by mastic seal.

Rear Roof rail:-

   Its created st the rear end of the roof.the fitment of the backdoor is to be considered while designing the rear roof rail.

Heat Distortion Criteria:-

  Heat distortion temperature is the temperature at which metal soften amd deforms under a specified load.While designing roof,this criteria is taken into consideration.We create bow roofs when the roof is long and flat to increase its strength.The position of the bow roofs is to be justified and this justification is done by curvature study:

Bow-roof prediction Formula:

  

Roof length(L):-

    

    L=2091.73mm.

Create a sketch:-

    A sketch is created to get the intersection points and projected on the roof.

    

    

Rx curvature:-

    

    

Ry curvature:-

    

    

Calculation of "W":-

    

      Here we can see that the roof is completely satisfying the conditions of heat distortion.

 Snow Load Criteria:-

 

To MEASURE Ly:-

   

To MEASURE Lx:-

   

To MEASURE Rx AND Ry:-

  

TO MEASURE "S":-

  

TO MEASURE "Y":-

 

 After measuring all these values the Qr is found out.

 TABLE FRO CALCULATIONS:-

Judgement condition = Qr ≥ 3.1

                250 ≤ s ≤ 380

   

    It is observed that the roof is satisfying the condition that are given.

SECTION MODULUS STUDY OF THE SECTION OF THE ROOF RAILS:-

    The section modulus of the cross-sectional shape is of significant importance is designing of structures.Its a direct measure of the strength of the structure.

    A stucture that has a larger section modulus than another will be stronger and capable of supporting greater loads.

SECTION MODULUS:-

           S=I/Y

Where,

         I =moment of inertia in (mm^4)

         y=Distsnce between the neutral axis and the extreme end of the object(mm)

FRONT ROOF RAIL:-

I=8364.09 mm^4

y=62.32 mm

S=I/y=134.21 mm^3

BOW ROOF 1:-

I=1883.99 mm^4

y=30 mm

S=I/y=62.79 mm^3

CENTER ROOF RAIL:-

I=2998.63 mm^4

y=40 mm

S=I/y=74.96 mm^3

BOW ROOF 2:-

I=1248.87 mm^4

y=30 mm

S=I/y=41.63 mm^3

REAR ROOF RAIL:-

I=2767.43 mm^4

y=59.32 mm

S=I/y=46.55 mm^3

 DRAFT ANALYSIS:-

     In NX to check whether the sheet metal part we have designed can Deep drawn,there is an option called deaft analysis.This type of analysis is performed based on color ranges identifying zones on the analyzed element Where the deviation from the draft direction at any point,corresponds to specified values.

ROOF OUTER PANEL:-

FRONT ROOF RAIL:-

BOW ROOF 1:-

CENTER ROOF RAIL:-

BOW ROOF 2:-

REAR ROOF RAIL:-