Roof Design

Roof Design

Aim:

            To design and draft analyse the car roof using master section and parameters.

Objective:

            1. Design the front roof, bow roof, centre roof, rear roof

            2. Draft analyse the roof design

Introduction:

            Automobile roof is a one of the BIW part. It used to protect the car and passengers from sun, wind, rain. The roof panel is the section of material, usually sheet metal, that forms the roof of a vehicle. Its long, low hood was impressive, as was the flat roof panel. The roof is split into three sections – Front roof, Centre roof, Rear roof.

 

Roof Outer panel:

 

 

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Front Roof:

 

 

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Bow Roof:

 

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Centre Roof:

 

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Rear Roof:

 

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Heat distortion:

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> 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)s

l = Bow Roof Span (mm)

Snow load:

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

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 centre 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 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]

Draft analysis:

            Limit angle 7^o

 

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Conclusion:

                        The car roof has been designed and draft analysis was done on the roof.