Roof challenge

ROOF DESIGN

Automobile roof or car top is the portion of an automobile that sits above the passenger compartment, protecting the vehicle occupants from sun, wind, rain, and other external elements. 

OBJECTIVE-

1.For the Given Roof styling, Develop the essential flanges and reinforcements, Provide appropriate dimensions and check for Draft analysis, and submit your Section Inertia report on the 0-Y section.

2.Start with the creation of a roof ditch area the tool opening angle is only 3 degrees.

3.Do a curvature study on the roof and perform calculations to determine the position of the Bow-roof.

4.Develop the essential flanges and reinforcements, Provide appropriate dimension and check for Draft analysis. Do a curvature study on the roof and perform calculations to determine the position of the Bow-roof

TYEPS OF AUTOMOBILE ROOF:

1.Convertible- a convertible , carbriolet or spyder is a passenger car that can be drven with ar without o roof in place.

2.Hardtop- a hardtop is a rigid form of automobile roof ,which for modren cars tpically constructed from metal . a hardtop roof can be either fixed , detachable for separate stoing or retactable within the vechicle itself.

3.Sunroof : An automotive sunroof is amovable panel that is operable to uncover a windwon  in a automoblie roof .which allows light and fresh air into the passanger compartment.

4.T-top: A t-top is an automobile  roof with a removable panel on each side of a rigid bar running from the center of thone structural bar between pillars to the center of the next structural bar . the panels of a traditional T - top are usually made of auto grade safety glass.

5. Targa top : it is  a semi covertible car body style with a remoable roof section and a full width rool bar behind the seats .

6 vinyl roof :vinyl roof refers to a vinyl converting for a  automobiles's top. this converting was orginally designed to give the appearance of a convertible to models with a fixed roof but eventually . itevolved into styling statement in its own right.

DESIGN CONSIDERATION 

• Visibility criteria
• Head clearence 
• Curvature study
• Heat distortion and snow load condition
• Draft angle
• Emboss
• Minimum bend radius

Design Methodology

• Covertion the suface- Using command like wave geometry linker, offset surface extracting the requied surface from the given Stying Surface.
• Draft Analysis-using law extension and given minimum draft angle in emboss.
• Modeling Reinforcement and Emboss Parts- is provied to gives the strength to centre bow roof or other roof rail.
• Curvature Study & Analysis of Roof-  Heat Distortion Criteria, Snow Load Criteria and Moment of Inertia.
• Minimum Clearence for Mastic - 5 mm
• For Ditch Aear -we used there welding operation so that no any clearence or requried in  this case .
• Minimum Bend Radius - is (3+t) where is t is thickness of the part.fr

FRONT ROOF RAIL

Front roof rail is used to povide stength to the roof front and it alos acts as link between windshield glass roof panel and heeadliner.spot weld are applied at wind shield end of thae rail and the other end is joined with roof using mastic sealent which also increases the stength.

Rear Roof Rail-

Rear roof rail is again used to strengthen the roof and it acts as a link between back glass and roof which connected to the back door of the car. spot weld are applied at back doorend of the rail and the other end is jioned with roof using mastic sealent.

Centre bow roof Rail 

This is roof rail that will be at centre of the roof to provide stength and stability to the roof. Here the cnetre roof rail is jiot with the roof throught mastic sealent.

and Reinforcement is provied to gives the strength to cemter bow roof or other roof rail.

Bow Roof-

bow roof used to add support and strengthening on linear curvature area

Ditch Area-

Ditch area is a extended portion of the main roof . the rails support of the roof are attached to the ditch area using spot weld.

• ANALYSIS

 Heat Distortion Criteria

heat distortion temperature at which the metal saften and deforms under a specific laoad . this study is done to check the ability of the roof to withstand high temperature with repect to the positioning of the reinforcement which contribute to increased strength 

W = [1.73 x 10^(-3) x L] + [1.85 x 10^(-8)  x (R^2)/t] + [ 1.10x10^(-3) x l] - 2.68            

Judgement Condition : OK< 2.7> 3.1

Where

L = Roof Length in X-Direction[mm](Roof dimension in 0-Y)

R = Roof curvature

      R = 2(Rx*Ry)/(Rx+Ry)

Rx = X curvature

Ry = Y curvature

t  = Roof plate thickness [mm]

l = Bow Roof Span [mm]

From the above table , its is concluded that the designed roof satisfies the heat distortion criteria

Snow Load Criteria -

Snow wload criteria study is done to check the ability of the roof to withstand snowload and bounce back to its original shape without any parmanent deformation once the load is removed .

Qr =  [Iy x t²] / [α x s x [(Rx + Ry)/2]² x 10^-8]

Note: The Qr value given over here is correct. There was a typo error in the formula given in the video.

Where

α = My x Lx² x 10^-12 , My = Y(Ly-Y)

Judgement condition = Qr ≥ 3.1

                250 ≤ s ≤ 380

t = Roof plate thickness [mm]

Ly = Distance between the front and rear roof Rails on the Vehicle along with 0Y[mm]

        Length of Roof panel with the center point between Roof rail Front /Rear as the front and rear reference point.

Lx = Distance between the Left and Right end of the roof on the Roof BOW [mm]

        Width of the roof panel exposed on the surface.

Y = Distance front Front Roof Rail to Roof BOW[mm]

s = Distance for which Roof BOW bears divided load [mm]

        s = L1/2 + L2/2

Iy = Geometrical moment of inertia of Roof BOW (Y cross-section )[mm4]

Rx = Lateral direction curvature radius of roof panel Y cross-section on Roof BOW [mm]

        Roof panel curvature Radius of the Length Lx in Front view 

Ry = Longitudinal Direction curvature radius of the Roof panel X cross-section on Roof BOW [mm]

        Roof panel X curvature radius of length s in Side view

Section Modules 

Bow roof front side 

Centre Bow Roof 

Rear Bow Roof

• from the above results case 3 were failed to satisfy the jugde mental candition.
• Hence to increase the strength and stifness over the roof from rear bow roof rail to rear roof rail where the Qr result  were very low emboss were provided
• The embosses over there will increase the roofs stength nad stiffness drastically.