Roof Design

OBJECTIVE :



To design a car roof and to do a curvature study on roof and perform calculation to determine the position of bow-roof.







INTRODUCATION :






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.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.



















TYPES OF ROOF :

• Convertible roofs. Roof modules. Roof modules.
• Hardtops.
• Sunroofs.
• T-tops.
• Targa tops.
• Vinyl roofs.
  
  
  
  
  
  COMPONENTS OF ROOF :
  
  
  * Front rail roof
  
  
  
  
  
  
  
  
  
  
  
  
  
  * Rare rail roof
  
  
  
  
  
  
  
  
  
  
  
  * Bow roof 1,2 and 3
  
  
  
  
  
  
  
  
  
  * Reinforcement center roof
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  SECTION INERTIA REPORT :
  
  
  
  
  
  
  1) FRONT RAIL ROOF
  
  
  
  
  
  
  
  
  2) BOW ROOF 1
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  3) BOW ROOF 2
  
  
  
  
  
  
  
  
  
  
  
  
  
  4) BOW ROOF 3
  
  
  
  
  
  
  
  
  
  
  
  
  5) REINFORCEMENT CENTER
  
  
  
  
  
  
  
  
  
  
  
  
  6) REAR RAIL ROOF
  
  
  
  
  
  
  
  
  
  
  
  
  
  7) OUTER RAIL ROOF
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  DRAFT ANALYSIS :
  
  
  
  
  1) FRONT RAIL ROOF
  
  
  
  
  
  
  
  
  
  
  
  2) BOW ROOF 1
  
  
  
  
  
  
  
  
  
  
  
  
  3) REINFORCEMENT CENTER ROOF
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  4) BOW ROOF 2
  
  
  
  
  
  
  
  
  
  
  
  
  
• 5) BOW ROOF 3
  
  
  
  
  
  
  
  
  
  6) REAR RAIL ROOF
  
  
  
  
  
  
  
  
  
  
  
  
  7) OUTER ROOF
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  HEAT DISTORTION REPORT
  
  
  

  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

  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]
  
  
  
  
  

  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  

  HEAT DISTORTION TEST RESULT
  CASE	POSITION	L	R	T	l	Rx	Ry	W	JUDGMENT
  1	FRR-B1	2112.2603	3386.98	0.75	500	5704.48	2408.51	1.46	OK
  2	B1-RR	2112.2603	4780.23	0.75	277.23	4951.93	4620.05	2	OK
  3	RR-B2	2112.2603	4777.86	0.75	299.69	4235.81	5479.01	2	OK
  4	B2-B3	2112.2603	5599.65	0.75	366.54	3597.32	12629.41	2.33	OK
  5	B3-RRR	2112.2603	8591.36	0.75	183.1	5950.04	15449.8	3.5	NA

  
  
  
  
  
  
  
  
  SNOW LOAD REPORT :
  
  
  
  
  
  
  
  
  
  
  
  
  
  

  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)

  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

  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  

  SNOW LOAD TEST REPORT
  CASE	POSITION	Ly	T	Y	Lx	My	α	S	Rx	Ry	Qr	JUDGMENT
  1	FRR-B1	2112.26	0.75	500	1129.15	806138	9.10*10^-4	388.61	3253.07	2948.63	3.49	PASS
  2	B1-RR	2112.26	0.75	277.23	1085.82	508725.4	5.52*10^-5	288.46	5252.31	6191.01	2.27	FAIL
  3	RR-B2	2112.26	0.75	299.69	1064.29	543209.1	5.78*10^-6	333.215	3153.15	5569	3.24	PASS
  4	B2-B3	2112.26	0.75	366.54	1049.56	639876.2	6.71*10^-7	274.82	4316.82	4495.96	3.31	PASS
  5	B3-RRR	2112.26	0.75	183.1	1041.59	353229.2	3.67*10^-8	NILL	3780.33	7604.38	NILL	NILL

  
  
  
  
  
  
  
  
  FINAL ASSEMBLY
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  CONCLUSION
  
  
  
  Hence snow load test is not fulfilling requirment so to provide a strength to the roof I created emboss on roof top so that it gives a little strength to the roof.
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  UPDATED ASSEMBLY