Roof challenge

                                                                                     ROOF

ROOF IS THE UPPER COVERING OF THE VEHICLE OR AUTOMOBILE. IT IS NOT AS SIMPLE AS IT LOOK FROM THE OUTSIDE .IT CONTAINS SO MANY COMPONENTS INSIDE THEM . AND THIS COMPONENTS HAS SO MANY DESIGN CONSIDERATION TO BE FOLLOWED BY US DURING THE DESIGNING OF THE ROOF. 

LIKE WHAT WE SEE FROM THE OUTSIDE ROOF IS NOT JUST A SINGLE PANEL WHICH IS 0.75mm THICK.

IT IS ALSO A PANEL WHICH HAS REINFORCEMENTS INSIDE. LIKE,

FRONT ROOF RAIL

CENTER ROOF RAIL

BOW ROOF 1

BOW ROOF 2

REAR ROOF RAIL

THERE ARE CARS WHICH HAVE MORE REINFORCEMENTS AS BOW ROOF 3, BOW ROOF 4. LARGE VANS HAVE 3 OR 4 BOW ROOF IN BETWEEN AND THESE BOW ROOFS ARE POSITIONED IN THE MOST FLAT AREA OF THE CAR.

WHY THIS IS BECAUSE AS WE KNOW THE FLAT SURFACE IS WEAK AS COMPARED TO THE SURFACE THAT HAVE BEND IN THE SURFACE.SO TO IMPROVE STRENGTH OR TO INCREASE THE STRENGTH OF THE SURFACE WE GIVE REINFORCEMENTS TO THE SURFACES WHICH IS FLAT. AND THATS THE BASIC  CONCEPT WE WORK ON IT . APART FROM THAT FRONT ROOF RAIL AND THE REAR ROOF RAIL HAVE THEIR OWN FUNCTIONS.

REAR ROOF RAIL IS THE ONE WHICH JOINS WITH  THE BACK DOOR AND THE BODY SIDE OUTER. WHEREAS FRONT ROOF RAIL  IS THE ONE WHICH JOINS WITH THE WINDSHIELD GLASS AND THE BODY SIDE OUTER AND ALSO WITH THE INNER PANELS . AND HOW DO WE DESIGN THIS ROOF RAILS AND THE BOW ROOF IS THE IMPORTANT TOPIC NOW.

DESIGN CONCEPT SHEETS  

WHEN WE TALK ABOUT DESIGN CONCEPT SHEETS . IT IS THE SHEETS WHICH CONTAINS ALL THE INFORMATION THAT WHAT MY ROOF IS GOING TO HAVE TO WHICH REGION WE ARE GOING TO PRESENT THIS ROOF. WHAT ARE ITS MATERIALS . WHERE IAM GOING TO PRODUCE THE  PARTS . AND WHATS ARE THE THICKNESS WHICH IM  GOING TO USE FOR THE PARTS. AND ALSO THIS INFORMATION WILL HAVE DIFFERTIATION FROM ITS PARENT CAR. EVERY CAR HAVE A PARENT CAR AND A SUCCESSOR CAR . SO WE PRESENT THE MAJOR VARIATIONS IN THE PARTS  IN THIS SHEETS .

                                                                 DESIGN CONSIDERATION OF RAILS

FIRST IMPORTANT TOPIC IS FRONT ROOF RAIL

FRONT ROOF RAIL IS AN ADDITIONAL COMMODITY WHICH IS GIVEN AS A REINFORCEMENT AND HAVE CERTAIN FEATURES WHICH IS SUPPORTING BRACKET LAMP AND THE ROOM LAMP WHICH IS BEEN  MOUNTED ON THIS RAIL.

COMING ON TO THE DESIGN WHEN WE HAVE STYLING WE HAVE A EDGE POINT WHICH IS KNOWN AS STYLING POINT.LIKE WHAT WE KNOW ABOUT DEEP DRAWING CONDITIONS WE HAVE TO OPEN THIS AT A PARTICULAR ANGLE. WE USE 3 DEGREE. WE USE MINIMUM 7 DEGREE FOR SHEET MATERIALS . 

AND WHY WE USE PARTICULAR 21.5 mm LENGTH OF THIS FLANGE AND WHY WE HAVE THIS SPACE ABOVE THE 21.5 MM  LENGTH FLANGE . BECAUSE WE HAVE WINDSHIELD GLASS WHICH IS PLACED THERE WHICH IS 3.7 TO 4.7 MM THICK. AND BELOW THE WINDSHIELD GLASS WE HAVE A RUBBER PASTE ., AND THIS PASTE WILL BE UPTO 4 OR  5 MM THICK.AND THEIR IS ALSO A SEALANT WHICH IS RUNNING THROUGHOUT. 

AND BY KEEPING IN MIND ALL THESE POINTS . WE OFFSET THIS SURFACE WHICH IS EXACT OFFSET OF THE ROOF SURFACE TO A PARTICULAR VALUE.AND WE HAVE THIS 21.5 MM BECAUSE OF THE 5MM OF THE RUBBER AND THEN WE HAVE  ANOTHER MOULDING WHICH WILL BE AVAILABLE FOR 8MM. AFTER THAT WE HAVE WINDSHIELD GLASSES AND THE RUBBER DIMENSIONS WHICH WILL CONTRIBUTE TO MAKE 21.5 MM . ALL THE VALUES HAVE A MINIMUM MOST REQUIREMENTS . BY THESE MINIMUM MOST REQUIREMENTS WE GET 21.5 MM . WHICH WE CANT AVOID.

WHAT WILL HAPPEN IF WE CHANGE THE OPENING ANGLE. IF WE REDUCE THIS BELOW 3 DEGREE .. LET 2 DEGREE. IT IS IMPOSSIBLE TO MANUFACTURE. AND  IF WE GO MORE THAN THE 3 DEGREE WE ARE GOING INSIDE MORE THEN . WE ARE DETORIATING VISIBILITY CRITERIA. WE ARE REDUCING THE VISIBILITY FOR THE DRIVER. SO WE MAINTAIN AS MINIMUM AS POSSIBLE TO GET THE MAXIMUM VISIBILITY.

AND WHY THIS 32MM DOWN. THIS COMES WITH A REASON.. AND DEPENDS UPON THE  VISIBILITY CRITERIA WHAT WE KNOW. WHEN WE GET VISIBILTY CRITERIA LINE FROM THE PROJECT TEAM .. WE KNOW WHAT VISIBILITY CRITERIA WE SHOULD FOLLOW. AND FOR WHAT OFFSET VALUE WE SHOULD MEET THE VISIBILITY CRITERIA IS WHAT I SHOULD THINK.

IF WE HAVE VISIBILITY CRITERIA LINE SOMEWHERE DOWN WE SHOULD OFFSET THE LINE SOMEWHERE MORE DOWN. SO WE CAN INCREASE THE 32 MM VALUE . AS PER THE CONDITION.

AND ALSO THE LINE FROM THE 32 MM OFFSET SURFACE . WE HAVE DEEP DRAWING CONDITION. SO WE OPEN IT FROM THE CAR LINE BY  3 OR 4 DEGREE.AND IN THE STARTING I GIVE  THE TOLRENCE GAP OF 2 MM,THIS IS FOR THE ASSEMBLY TOLRENCE.

AND THIS INCREASE WHEN WE MAKE A PREMIUM CAR AND IT REDUCES WHEN WE MAKE A ENTRY LEVEL CAR.

AND WHEN WE DO THIS AFTER THAT THE CRITICAL VALUE WE HAVE IS 80 MM .MINIMUM 80 MM IS FOLLOWED SO THAT WE GET PROPER DIMENSION.

WHAT WE MEAN BY PROPER DIMENSION. AFTER THE ROOF WE HAVE OUR ROOF RAIL.BELOW ROOF RAIL WE HAVE HEAD LINER WHICH IS THE TRIM PART GOING IN AND AGAIN FROM THE AGRONOMICS AND PROJECT MANAGEMENT TEAM WE WILL KNOW WHEREFRONT DRIVER WILL BE SEATING. THERE SHOULD BE MINIMUM HEADROOM CLEARENCE IF THE PERSON IS SOMEWHERE TO SEAT FORWARD THEN THE 80 MM VALUE CAN BE REDUCED  AND IF THE DRIVER IS SEATING AT THE BACKWARD POSITION THE THE VALUE SHOULD BE INCREASED. 

SO WITH THESE WE WILL GET OUR FRONT ROOF RAIL AND AT THE END WE WILL INTRODUCE MASTICS. MASTICS IS A RUBBER KIND OF MATERIALS WHICH HOSES OUT AND JOINS THE ROOF RAILS AND THE ROOF OUTER.

ALWAYS ONT HE STEEL PART WE SHOULD HAVE ATLEAST A MINIMUM RADIUS OF 3+ THICKNESS.

WHY WE HAVE THESE CONSTRAINTS BECAUE STELL HAVE THE CAPABILITY TO ELONGATE ONLY THAT MUCH IF WE TRY TO RESTRICT ITS ELONGATION ITS RESULT IN TEARING OF PART AT SOME REGION.

REAR ROOF RAIL

HERE WE HAVE THE CONDITION OF REAR HEADROOM CLEARENCE AND THE REAR VISIBILITY CRITERIA.

SO THE VALUE SHOWN IN IMAGE IS WITH RESPECT TO THE REAR HEADROOM CLEARENCE AND REAR VISIBILITY CRITERIA.AND WHY WE HAVE A DIFFERENT DESIGN FOR REAR ROOF RAIL BECAUSETHAT IS THE AREA WHERE WE ARE MOUNTING OUR BACKDOOR.

BOW ROOF RAIL

HERRE ALSO WE HAVE SOMEWHERE A SIMILAR CROSS SECTION FOR THE BOW ROOF OR CENTRE BOW ROOF REINFORCEMENT.AND HERE ALSO IS THE CONDITION OF HEADROOM CLEARENCE AND BASED ON THE HEADLINER WHAT GOES INSIDE AND THIS ARE THE DESIGN CONSIDERATION WHICH WE KEPT IN THE MIND WHILE DESIGNING ROOF OR THE REINFORCEMENTS .

WE SHOULD HAVE ATLEAST 85MM CLEARENCE ABOVE THE HEAD LINER AND IT DEPENDS UPON PROJECT TO PROJECT AND REGION TO REGION ALSO. WHENEVER THEIR IS THE MASTIC INFORMATION THEIR WILL BE REMARKABLE IMPROVEMENT IN THE STRENGTH.

CENTRE ROOF RAIL

 AND AFTER THE DESIGNING HOW WE SHOULD KNOW THAT THE REINFORCEMENTS WE MADE IS ON RIGHT PLACE. SO THEIR IS 2 CONDITIONS THAT THE ROOF REINFORCEMENTS SHOULD FOLLOW 

1 BOW ROOF PREDICTION FORMULA

W=1.73*10^-3*L+1.85*10^-8*R^2/t+1.10*10^-3*i-2.68

R=2*(Rx*Ry)/(Rx+Ry)

Rx= X CURVATURE

Ry= Y CURVATURE

THE VALUE OF W SHOULD BE ALWAYS LESS THAN 3.5

HOW WE CAN MEASURE OR GET THESE VALUES.

FOR THAT FIRST WE HAVE TO MAKE VERTICAL LINE AT THE CENTRE OF TWO ROOFS RAILS , OR BOW ROOFS. EXAMPLE WE HAVE TO MAKE A VERTICAL AT THE CENTER OF THE FRONT ROOF RAIL AND THE BOW ROOF 1.

SO WE GET 4 VERTICAL LINES.

AFTER THAT WE HAVE TO DRAW A HORIZONTAL LINE AT 0 Y SECTION

AND AFTER THAT WE HAVE TO DRAW -3 Y LINE MEANS 300 BELOW THE OY LINE

AND THEN 100 DOWN AND 100 UP AFTER THAT WE WILL GET POINTS INTERSECTED AT VERTICAL LINE AND THE HORIZONTAL LINE. KNOW WE HAVE TO MAKE ARC WITH THESE POINTS ON THE SURFCE OF X CROSS SECTION AND Y CROSS SECTION AND FROM WE GET Rx AND Ry.

W1=1.80

W2=1.256

W3=1.287

W4=1.94

2 SNOW LOAD CONDITION

Qr=Iy*t^2/ALPHA *s*[(Rx+Ry)/2]^2*10^-8

Iy IS SECTION INERTIA OF BOW ROOFS

ALPHA =My*Lx^2*10^-12

My=Y(Ly-Y)

Ly LENGTH OF STYLING

Lx= CURVATURE AT THE VERTICAL LINES

THE ONLY DIFFERENCE IS THAT HERE WE MEASURE Rx AT 100 UP AND DOWN FROM THE 0Y SECTION.

Qr1=6.83

Qr2=49.95

Qr3=8.02

HERE VALUE OF QR SHOULD ALWAYS GREATER THAN 3.1

DRAFT ANANLYSIS OF DIFFERENT COMPONENTS.