Roof Design

ROOF

An 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.

TYPES OF ROOF

• Convertible roofs
• Hardtops.
• Sunroofs.
• T-tops.
• Targa tops.
• Vinyl roofs

FRONT ROOF RAIL

REAR ROOF RAIL

BOW ROOF 1

BOW ROOF 2

CENTER ROOF RAIL

ROOF

After Completing the design part, we have done calculations to calculate the strength of the roof.

Heat Distortion Calculations:

We have a data to calculate

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]

• L value

• Rx value

• Ry value

• Ix1

• Ix2

• Ix3

• Ix4

after all the calculations

according to the condition all the values are ok

Snow Load Calculations

We have a data to calculate

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

• calculate Rx value

• calculate Ry value

after all the calculation

according to the condition all the values are ok

DRAFT ANALYSIS

ROOF

FRONT BOW

REAR BOW

CENTER BOW

BOW RAIL1

BOW RAIL 2

ROOF IS FULLY DESIGNED AND ALL THE ANALYSIS ARE DONE ON IT