Roof design

Rollover crashes are usually very destructive events.Vehicle damage often includes deformation of the roof and its supporting structures. Head and neck injuries are common, and associated with roof deformation. Strengthening of the roof is suggested as an appropriate counter measure for such injuries.

In order to achieve the strength we introduce reinforcements in form of front roof rail,Rear roof rail,Center roof rail & bow roof rail.

The designed roof for given surafce:-

The given surface have good curvature at the start but it become flat as we move towards rear end. hence the one Bow roof rail reinforcement is given at the back side of the roof & other is given at the front.

The center roof rail is placed at the curvature starts decrease & the roof start to become flat to increase the strength. Appropriate distance is maintained between reinforcement & roof inner suraface for mastic sealents.

Front roof rail section:-

1. It is the placed at the front of the roof & which will act as a reinforcement to the front roof
2. The size of this should not disturb the visibility criteria & the space required for the front windshield glass ,rubber paste & sealent.
3. minimum Thickness of is 0.65 mm is required .

Center roof rail section:-

Bow roof section:-

1. This is additional part added to give the strength & no.of bow roof depends on the length of tha car roof.
2. The roof area which is flat in shape is been strenthened by using the bow roof.
3. The thickness given here is 0.65mm.

Rear roof rail section:-

1. It is the placed at the rear of the roof & which will act as a reinforcement to the rear roof.
2. The size of this should not disturb the visibility criteria & head clearance for rear seat passenger.
3. Head room clearance is minimum 80mm.which depends on car to car & region to region.
4. 0.65 mm thickness is considered for rear roof rail.

Heat Condition:-

Bow – roof prediction Formula :

W = 1.73x10^-3 x L+1.85x10^-8 x (R^2)/t + 1.10x10^-3 x l-2.68

Judgement Condition : OK<2.7mm<NG

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]

The value of W lies below 2.7,so the bow roof placements satisfy the condition of heat distortion.