Roof Design
REPORT :
Parameters for desiging Front Roof Rail design :
1.Head Room Clearence :
2.Visibility Criteria :
1.Head Room Clearence : It is defined as the distance between the tip of the head and the roof is called has head room clearence,The head room clearence should be more so that when any crash happens to the car the head will be protected at this area,so by giving more head room clearence more safety is given to the passenger.
2.Visibility Criteria : If the depth of the front roof is more from the roof then it effects the front visibility of the driver who is driving the car.Therefore the design of the front roof is considered without effecting the visibility of the customer.
Fig .1
Fig .2
Parameters for desigining the Rear Roof Rail :
Head Room Clearence : It distance between the head the rail roof rear is called had head room clearence,More head Room clearence more the safety of the passenger.
Fig .3
Back Door Mounting :
The roof rail rear is designed by taking the considerations of the assembly of the back door that is why the roof rail rear shape is different from the roof rail front.
Fig .4
Fig .5
Centre Roof Rail :
Additonal of more roof rail is given with the centre rail to give more strength for the centre Roof Rail.
Fig .7
Fig .8
Bow Roof Rail : Embosses are given to improve the strength in the bow roof rail,Depending up on the the length of the roof no of bow roof rails can be increased up to 4 or more is the length of the roof is less then only 1 bow roof is given or no roof rail is present.
Fig .9
Fig .10
Roof Outer Panel :
The parameters for desiging the outer roof rail depends up on the A,B and C pillars of the car body and also the type of car like hatch back,micro hatchback,Suv and muvs and sedans.
Fig .11
Spot welding : It is techinque used to join two joints for 0.3 mm to 6 mm,The centre roof is joined by using the spot welding.
Mastic : In the bow roof rail the mastics are used to join the sheet surfaces the clearence used for joining the matics is 5 mm
The given below figures shows that optimum gap is maintained thorugh out the roof desgin by following the given master sections of the front,bow,centre and the rear roof rails.
Fig .12 Fig .13
Fig .14
Heat Distortion Criteria :
In the Countries like India and some parts of the Asia the Sun rays incident on the roof when the car is in a constant position for a long period of time,this secenario effects the roof outer panel it may change is colours and also it effects the thickenss of the roof and the roof funtions may change gradually this is called has hear distortion criteria.
Fig .15
Conclusion :
All the sections of the roof are satisfying the given judgment condition W < 2.7 the roof can be taken to production.
Snow Load Prediction:
In winter season in the area like canada,USA and UK the snow falls on the surface and certain amount of snow will be deposited on the roof and for certain mass how the roof behaves till the certain mass and the roof should be retracted to the original shape,this prediction is studied in the snow load prediction.
Fig .16
Conclusion :
1.Therefore from the above obtained data the snow load predication is vaid for the case 1 and case 3 where as in case 2 modifications are requried in the thickness or on the bredth of the centre bow roof
2.Where as 's' is not in the given input limits and cannot satisfy the requried condition and has failed in all the three cases the bow roofs placements should be changed to satisy the given input limits.