Roof Design
AIM
To create the roof assembly and develop the required flanges from the given styling surface and
follow the master section
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
THERE ARE THREE TYPES OF ROOF
HARDTOPS ROOF
SUN ROOF
CONVERTIBLES
HARDTOPS ROOF
hardtops roof are referring to the common rigid forms of automobile roofs which we see around. In modern-day cars, this type of roof is made from metal or plastic.
SUN ROOF
This type of roof is also quite popular. You might have been seeing it around. A sunroof is an operable type of roof that allows for an opening in the roof of an automobile; say a window in a roof. It can allow either light or air or both to enter the vehicle. They are either operated manually or automatically.
CONVERTIBLES
convertibles are passenger cars that can be driven with or without the entire roof in place. They were first introduced as open-air vehicles; no roofs, no sides.
while Designing the roof use the following mastersection given in the question
Bow–Roof Prediction Formula
W = [1.73 x 10^(-3) x L] + [1.85 x 10^(-8) x (R^2)/t] + [ 1.10x10^(-3) x l] - 2.68
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]
Judgment Condition
OK< 2.7
L = 2028.513mm
t = 0.75mm
|
AREA |
Rx |
Ry |
I |
R |
W |
RESULT |
|
FR – BR1 |
2407.539 |
2161.816 |
457.813 |
2278.07 |
1.46< 2.7 |
OK |
|
BR1 - CR |
2437.439 |
2351.645 |
352.924 |
2379.26 |
1.35 <2.7 |
OK |
|
CR – BR2 |
2751.241 |
2202.242 |
354.743 |
2246.36 |
1.34 <2.7 |
OK |
|
BR2 - RR |
2762.235 |
1887.11 |
410.22 |
2238.6 |
1.40 <2.7 |
OK |
Snow Load Prediction Formula
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)
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]
The width of the roof panel is 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
Judgment condition
Qr ≥ 3.1
Ly=1830.75mm
t = 0.75mm
Iy=611.8mm4 for bow roof 1 & 2
Iy=673.2mm4 for center roof
|
AREA |
Rx |
Ry |
y |
Lx |
L1 |
L2 |
Qr |
RESULT |
|
FR – BR 1 |
1355.37 |
1742.07 |
490.11 |
1195.12 |
490.11 |
440.97 |
33.2 ≥3 |
OK |
|
BR - CR |
1435.56 |
1742.07 |
440.97 |
993.43 |
440.97 |
441.00 |
56.62 ≥ 3 |
OK |
|
CR – BR2 |
2120.89 |
1742.07 |
441.00 |
1011.00 |
441.00 |
522.65 |
39.6 ≥3 |
OK |