Roof challenge

Front roof rail:

Front roof rail is the one which joins the wind shield glass, body side outer and the inner panel also. Here the front roof rail is designed based up on the master section given.

Rear roof rail:

Rear roof rail is the one which joins the back door and the body side outer.

Bow roofs:

The bow roofs are given to improve the torsional stiffness and load bearing capacity of the roof structure. The number of bow roof present is depends on the overall size of the roof.

Joining process:

Mastics are introduced between the roof outer panel and the reinforcements for joining. where ever the mastic are introduced there is remarkable improve of the strength.

Spot welding is also introduced to join the reinforcements and the outer panel.

Styling Surface to Extracted Surface:

The styling team has provided the solid dump outer panel from that we are extracting the surface to model the necessary reinforcements like Ditch area, Front Roof Rail, Bow Roof Rails and Rear Roof Rail.

Design considerations for a roof:

• Visibility criteria
• Head clearance
• Curvature study
• Heat distortion and snow load criteria
• Draft analysis.

Bow roof rail calculations-

Heat Distortion calculations

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]

Procedure to measure the parameters:

a) On plane parallel to the top plane draw sketch in which 0Y line is offset by 300 mm.

b) Draw lines perpendicular to 0Y line passing through point exact midpoint of the two adjacent parts (e.g. midpoint between front rail and bow roof 1)

c) Offset these reference lines on both sides by 100 mm

d) Mark intersection points of reference line and 100 mm offset lines.

e) These reference points are then projected on to roof outer panel surface to create curves.

f) Take all necessary measurements required to calculate W value as per mentioned formula.

i HAVVE ATTACHED ALL THE DETAILS IN ATACHMENT:

HEAT DISTORTION CRITERIA IS SATISFIED:

	BOW and FRT RAIL	BOW and CTR	CTR and RR
Rx	3614	5681	4119
Ry	4991	6587.02	2639.41
R	4192.323998	6100.554225	3217.2448
ROOF SPAN	2111	2111	2111
l	340	410	721
t	0.75	0.75	0.75
W	1.779560986	2.341043459	2.0204464
	OK	OK	OK