Roof challenge

ROOF DESIGN

Objective

1. The objective this challenge design car roof with essential flanges and reinforcement like ditch area front roof rai,bow roof,cntre roof railand rear roof railfor the given styling surface
2. Perform a curvature study on the roof and perform the calculation for the heat distortion and snow load criteria to determine wheather the roof are at the correct position.
3. Finding moment of inertia and section modulus for bow roof ,centre roof rail,front roof rail,rear roof rail.
4. Perform the draft analysis for each reinforce ment.

• rear roof rail
• front roof rail
• bow roof rail
• centre roof rail

FRONT ROOF RAIL

Front roof rail is the one which joins the wind shild glass, body side outer and inner panel .it is designed based on the master section.

REAR ROOF RAIL

CENTRE ROOF RAIL

Cntre roof rail is providing effectively support to that flat area of the roof as it is more susceptible to failure under the action of load generally cetre roof rail is placed at the centre of the roof which is conected to the B-Pillar support structure .this central roof rail helps in adding the strength to the roof.

BOW ROOF

Bow roof give to improve the torsional stiffness and load bearing capacity of the roof structure .the number of roof is depend on the roof length and own design think.

BOW ROOF 1

BOW ROOF 2

COMPLETE ROOF WITH REINFORCEMENT

MOMENT OF INERTIA OF BOW ROOF

FRONT ROOF RAIL ( S= 345.36 mm^3)

CENTRE ROOF RAIL ( s=395.4186)

REAR ROOF RAIL (s=409.0511)

BOW RAIL

HEAT DISTORTION CURVATURE STUDY

The heat distortion study is important role in sheet metal usage .sheet metal have tendency to change in hihg temperature .to avoid any failure of sheet metal components this study is done to detremine its capacity.

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]

RESULT:

	Rx(mm)	Ry(mm)	Rx*Ry(mm)	Rx+Ry (mm)	R (mm)	L (mm)	t (mm)	l (mm)	W(mm)	OK/NG
FR-BOW 1	5775.6484	2294.0700	13249741.725	8069.7184	3283.810	2029.96	0.75	405.19	1.54	OK
BOW1-CR	4694.2672	6407.6572	30079255.0228	111010.9244	5418.7461	2029.96	0.75	454.644	2.056	OK
CR-BOW2	2972.6118	8321.9056	24737794.785	11294.5174	4380.4961	2029.96	0.75	348.2798	1.68	OK
BOW2-RR	2876.0562	14458.6482	41583884.7992	17334.7044	4797.7610	2029.96	0.75	390.4428	1.82	OK

SNOW LOAD PREDICTION

Qr = [Iy x t²] / [α x s x [(Rx + Ry)/2]² x 10^-8]

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

RESULT:

	ly	α	Lx	Ly	Y	S	Rx	Ry	t	Qr	OK/NG
FR-BOW1	176.4092	0.834499	1110.5520	1982.4451	438.1496	494.8773	4531.9258	2661.8235	0.75	6.4024	OK
BOW1-CR	132.6353	0.859442	1074.4249	1982.4451	503.5769	487..552	3530.4340	11669.7256	0.75	2.81	NG
CR-BOW2	45.49	0.683440	1066.7862	1982.4451	373.1801	441.9935	3224.2977	5683.0667	0.75	8.7682	OK

DRAFT ANALYSIS:-

REAR ROOF RAIL

FRONT ROOF RAIL

BOW 1

CENTRE ROOF RAIL

BOW 2

FINAL ROOF IMAGE