Roof Design

Project Objective: In this project, I am going to the Design of Roof and Develop the Essential Flanges and Reinforcements, and check for Draft analysis and also section modulus report on the 0-Y section.

01.About Roof design:

The roof is an essential part of a vehicle that plays an indispensable role in providing effective protection for you and those who drive with you from heavy snow, harsh rain, strong wind, harmful UV rays, etc. Like many other automotive body panels, the roof is subjected to environmental conditions. Hail and snowstorms may burst, tree limbs and branches may fall, etc. All this can damage the roof and cause sharp dents, dings, and scratches. Your vehicle can also become ruined in an accident. Though a defect may seem insignificant at first, it can lead to serious consequences. Whether your roof was dented due to downfall or roughed up in a collision, it is urgently necessary to find a replacement for it.

The roof panel is attached to the Biw of the car with the help of the front and rear roof rail. This attachment is done with the help of sealants. 1-2 bow roofs are attached depending upon the length of the roof along with the central roof rail. Longer the roof, more the number of the new roof rail. Other dimensions like strength and material are governed by factors like headroom, overall space, visibility, ergonomics, and the rules and regulation of the states where it is sold.

OK<2.7mm

For our arrangements :

Position	L(mm)	Rx (mm)	Ry (mm)	R (mm)	l (mm)	t (mm)	W	Judgment
FRR & BR1	2033.7	2494.67	5739.5	3477.74	396.9	0.75	1.573227	OK
BR1 & CRR	2033.7	6535.52	4887.09	5592.36	476.2	0.75	2.133558	OK
CRR & BR2	2033.7	11211.19	3854.76	5736.97	476.1	0.75	2.17386	OK
BR2 & RRF	2033.7	15234.03	3182.48	5265.06	267.7	0.75	1.816552	OK

 

03.Heat Distortion Criteria for Bow Roofs.

Snow Criteria: 

The formula for snow criteria is given as:

 Ly= Distance between the front and rear roof rails(mm).

Lx= Distance between left and right end roof rails (mm).

 Y= Distance between center of the front roof rail to center of bow roof rail(mm).

 S= Distance for which roof bow bears the divided load (mm).

ly= Geometrical moments of inertia of roof bow (Y cross-section)(mm).

Rx= Lateral direction of the curvature radius of roof panel Y cross-section on roof bow.

Ry= longitudinal direction curvature radius of the roof panel  X cross-section on roof bow.

 t= Roof sheet thickness(mm)

 

Position	Iy	Alpha	My	Lx	Ly	Y	S	Rx	Ry	t	Qr	Judgment
FRR & BR1	764.4177	0.923932	753136.9	1107.6	2033.7	486.9	516.7	2558.84	4558.8	0.75	7.111528	OK
BR1 & CRR	879.2184	1.178191	1033710	1067.6	2033.7	1033.4	546.5	6458.7	3783.35	0.75	2.928866	NOT OK
CRR & BR2	769.0689	0.786087	716958.6	1047.1	2033.7	1579.9	463.2	11868.28	4320.64	0.75	1.813314	NOT OK

For the section which are NOT OK , we should change Iy and thickness.

Hence those 2 section does not pass Snow load test

04.Draft Analysis:

Draft analysis for Bow Roof 1

Draft analysis for Front roof , center roof, Bow roof 2 and rear roof rail

Thus our design is safe from draft analysis for a 3-degree tool opening angle.