Roof Design

ROOF DESIGN--

Firstly Make the part file as assembly design after that starting design by extraxting half part of the outer roof 

Then start with outer flange of front roof rail and as followed according to master section given make the outer flange first as given picture below

 

After that making rear outer flanges according to master section given as shown in below picture

Then makes the side flange and complete the outer of roof

Now Start the second model in assembly 

Making the front roof rail following all the parameter according to mater section

Second model then real roof rail following all the dimensions of master sections

Then the third model of the assembly was the first bow roof rail and it is also made according to the dimensions given in the master section and same made in 2nd roof rail as the same parameters.

And like this I  made the centre roof rail and by increasing some length as given in mater section of centre roof rail and made the flange joining to the side flange of outer with some clearance between the outer and inner and this flanges also added in bow roof rail 1 and 2. 

So after making all the models of one side one by one give trim to the respective plane and give the mirror geomtry of every model like outer roof ,front roof rail,rear roof rail,bow roof rail 1& 2,centre roof rail, after giving mirror geomtry I give thicken one by one to every part respectively.And our file design is looks like that.....

Now the calculation part comes

Bow–Roof Prediction Formula

W = [1.73 x 10^(-3) x L] + [1.85 x 10^(-8)  x (R^2)/t] + [ 1.10x10^(-3) x l] - 2.68 

   According to it 

L= 1999

Rx= 5320

Ry= 2111

t= 0.75

I= 381

according to this calculation W= 3.1

NOW

Snow Load Prediction Formula

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

W= 2.9

all parameter comes into model 7