Roof Design
Design roof and reinforcement for a car
Here I design the roof and it's reinforcement based on the master section which is given from the question. And also the heat distorsion is calculated while design the roof and it's reinforcement. According to the indian heat range the automobile or car were passed out these kind of calculation.
Introduction
Automobile roof or car roof is the component which protect passenger from the direct sunlight, wind, rain and pollutants.This roof commonly have some types
- Convertible roofs
- Hardtops
- Sunroofs
- T-tops
- Targa tops
- Vinyl roofs
Hardtops
From these roofs, I design hardtop which is confirmed from the master section.The hardtops are looks like a normal SUV type of roofs. Basically the roofs contains the outer roof and the reinforcements.The reinforcements are
- Front roof rail
- Bow roof rail
- Center bow roof
- Rear bow roof rail
Outer roof
The outer roof is extracted from the given master section. I untrim the extracted surface and trim the untrim surface from the extracted surface.
Using the law extension tool I expand the side surface of the roof. After that sew all the components of the outer roof and thicken it to 0.75mm.
Front roof rail
The front roof rail is 32mm offset from the outer surface. And it is 7 degree slanding.The clearance value from the outer surface is 0.2mm.
Bow roof rail
The bow roof are comparatively small from center roof rail or center reinforcement rail. It is 65 to 75mm width and 0.75mm thickness. The bow roof rails are having the clearance value of 5mm from the outer surface.
Center roof rail
Center roof rail is also known as center reinforcement roof rail. Center roof rail having 80 to 90mm of width and 0.75mm of thickness. The clearance value is 5mm from the outer roof surface.
Rear roof rail
The rear roof rail is having the 3mm clearance value and 0.2mm clearance in the spot welding area. End of the rear roof rail is connected to the rubber sealant.
Draft analysis
Draft analysis ensure and show the critical area in the components.The draft analysis is tested every component in the roof design.
Outer roof
Front roof rail
Bow roof rail1
Center bow roof
Bow roof rail2
Rear roof rail
Bow roof prediction calculation
The Bow roof prediction calculation is also known as the heat distorsion calculation.
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]
Judgement condition
If the w value is 2.7 or less than 2.7 is acceptable.
OK<2.7
the value is ok when the value is 2.7 t0 3.5
| Section | L | I | t | Rx | Ry | R | (R^2/t) | w |
Result OK (or) NG |
| FRR to BR1 | 2135.4833 | 444.4081 | 0.75 | 3992.3851 | 2365.8113 | 2971.0407 | 11769443.7880 | 1.7209 | OK |
| BR! to CRR | 2135.4833 | 324.8200 | 0.75 | 3569.9174 | 6626.2559 | 4640.0125 | 28706289.0976 | 1.9027 | OK |
| CRR to BR2 | 2135.4833 | 325.3971 | 0.75 | 2528.2655 | 5762.8740 | 3514.6135 | 16470010.9799 | 1.6770 | OK |
| BR2 to RRR | 2135.4833 | 405.0569 | 0.75 | 3343.0059 | 234192.1048 | 6591.9146 | 57937785.0073 | 2.5037 | OK |
Conclusion
From the given master section I designed the outer roof, front roof rail, bow roof rail1, center roof rail, bow roof rail2 and rear roof rail. And also the draft analysis was tested to all the components of the roof design. The heat distorsion calculation was tabulated above using the formulae given in the question.