Roof Design
from the above input we start preparing the roof firstly we have created the outer panel in which we create the flate surfaces for the sopt welding purpose with all side to do that fistly we trim the part into two portion and then we made the low extension trim and edge blend commmmand to make the desire output according to the mastersection requirement. we have also added some additional edge fillets which are require for the design then we made the inner part of hood which are going to help to reduce the failure of the part in snow load condition and heat distortion
Bow roofs are placed on the flat regions of the roof which provides strength in bigger curvature region and in between Front roof rail,centre roof rail and rear roof rail.Bow roofs are also design based on the design consideration similar to Front Roof Rail(FRR).we have provided two roof rails front and rear roof rail for improve the strength
we give support at the middle of the external roof,provided there is an maximum chance of roof buckling.It increase strength of the particular cross section and it is design considering the head room clearances
Reinforcement roof centre along with Bow roof centre which icrease the section modulus,thus increasing strength of the middle portion of the roof to withstand for the snow load condition
Rear Roof Rail is designed based on the master section of the rear roof rail we created the rail roof end part with having small space in it in which the D pillar is going tro assemble in it which is just above the tail lamp assembly
in this way we have provided various support to the outer panel to avoid the daqmage in snow load condition and the heat distorsion condition
we made the draft analysis on the part to get to know that the part draft angle is sufficent to produce or not. after completing the design of fron and rear roof rail,fron and rear bow and center bow roof. we thicken the part
for the thick part we check the section analysis for the part and we also made the part projection to do that then we made the sketch in which we are ploting a points on the surface to get the arc which is require for the Ry,Rx for the calculation of the heat distortion and the snoe load criteria calculations
bow's R'x R'y I L t R W OK/NOK
FR &1st 5732.36 2658.52 426.4 1920 0.75 3632.42 1.4361 OK
1st &CTR 6477.52 4902.60 423.6 1920 0.75 5581.08 1.1879 OK
CTR & 2ND 10868.31 3908.54 439.8 1920 0.75 5749.42 1.94076 OK
2ND &RR 14960.98 3224.09 347.5 1920 0.75 5304.96 1.12359 OK
FROM THE ABOVE TABLE WE GET THAT WE HEAT DISTORTION CRITERIA IS NOT MORE THAN 2.7
THATS WHY IT SATISFY THE HEAT DISTORTION CRITERIA
For the snow load criteria we get the following table
bow's R'x R'y ly t LX LY Y L1 L2 S My Alpha Qr
FR&1S 2703.58 4460.714 2757.38 0.75 1130 1900 450 450 500 475 652500 0.834 30.527
1ST&CTC 6397.71 3779.956 10213.85 0.75 1080 1900 950 500 510 505 902500 1.053 14.7319
CTR&2ND 11520.84 4304.218 3793.96 0.75 1052 1900 1475 510 420 462 626875 0.694 10.6348
2ND &RR 16924.33 910.511 68682.86 0.75 1039 1900 1900 420 420
As per standards the Qr value supposed to be greater then the 3.1.In the Above Design,we have found the Qr value is greater than 3.1 in all Components.hence the Snowload criteria is satisfying.
conclusion
Hence the roof , front roof rail, bow roof rails , central roof rail and the rear roof rail is designed by following the master sections and the moment of inertia , section modulus and draft analysis are carried out.