Roof challenge

OBJECTIVES:

• Create a roof of the car by the given styling surfac based on the master section provided.
• To validate the designed roof is satisfy the heat distortion criteria and snow load condition.
• To familiar about the tools and oprations involved in creating the roof of the car.
• To prepare section modulus for the bow roof 1 reinforcement and bow roof 2 on the 0-y cross section
• draft analysis for all the part for checking the tools feasibility.

ROOF INTRODUCTION:

The roof is an important part of an automobiles as it protects the occupants from various environmental conditions like Heat,snow,rain and winds. the roof must be design in such a way that it would able to withstand any load or impact due to accidents or objects falling on it and other envirmental factor. so,the design based on the standards and design intent which make the roof to withstand the above-said conditions. Also other factor Headroom ,aesthetics play a role in the design. The roof is an assembly of many parts like front roof rail, bow roof , bow roof center and reinforcement center. The number of bow roof is based on the length of the roof and somtime bow roof center is avoided in case like small car. the roof is attached to the body of the car using mastic sealants provided between bow roof and the front or rear roof rail.Roof is connected to A-pillar,B-pillar and C-pillar to cover the front and rear door. roof is spported by reinforacment bow-roof with front and back roof rail.

Types of roof reinforacment are as follow:-

• Front roof rail
• center roof rail 
• front bow roof rail 
• rear bow roof rail
• rear rail 

DITCH AREA:

It is the extanded portaion of the main roof concealed by other BIW panels and not a styling surface. Headroom clearance .visiblity criteria, clearance for windshield and back door are some of the factors to be considered while designing the ditch area.

FRONT ROOF RAIL:

It is the support that is joined with the windshield glass,bodyside outer and the inner panels. it is usually made from body side outer scrap and therefor the thickness of the rail is 0.65mm. A draft angle of 3-5 degrees is provided for deep-drawing opration. the visiblity critetaria and the headroom clearance of the passenger are taken into considration for the bottommost flange. windshield  end and the roof end are spot welded and the other end of the front roof rail is joined with the roof using mastic sealants for increase strength.

 

RAER ROOF RAIL:

It is the support that is joined to the backdoor,the bodyside outer and the inner panels. inputs from the backdoor desiign is also taken to accommodate the required clearence along with headroom clearance and the rear visibility criteria while designing the rear roof rail. spot welds are applied at the backdoor end of the rail and the other end joined with the roof using mastic sealants.

 

CENTRE ROOF RAIL AND BOW ROOFS:

Similar to other rail designs,we have to take into consideration the headeoom clearance and the visibility criterial while designing the centre roof rail and bow roofs. Unlike the front and rear roof rails,spot welds are not applied for joining these rails to the roof. Mastic sealants are introduced at both the ends instead of spot welds since centre roof rail and row roof are fully positioned under the styling surface of the roof.

CENTRE ROOF RAIL

BOW ROOF 1

BOW ROOF 2

Calculations to determine bow position:

1. Heat Distortion criteria:

Heat distortion temprature is the temperature at which the metal softens and deforms under a specific load. This study is done to check the ability of the roof to withstand high temperature with respect to the positioning of the reinforcements which contribute to increased strength.

W=[1.73X10^(-3)XL]+[1.85X10^(-8) X (R^2)/t]+[1.10X10^(-3)XI]-2.68

Jugement Condition : OK <2.7

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]

I= Bow Roof Span[mm]

2. Snow Load Criteria:

Snow load criteria study is done to check the ability of the roof to withstand snowfall and bounce back to its original shape without any permanent deformation once the load is removed.

SECTION MODULUS OF MASTER SECTION:

FRONT ROOF RAIL:

 

BOW ROOF 1:

 

CENTRE ROOF RAIL:

 

BOW ROOF 2:

 

REAR ROOF RAIL:

FINAL IMAGE OF THE ROOF:

https://drive.google.com/drive/folders/1eI4kYEGjLU3YfKSO4UacmZxBwu_f-Anq?usp=sharing