Roof challenge
Title- Roof Design
Objective- To design a roof by using a given class A surface and given master section for front roof rail and rear roof rail, also add at necessary flanges, reinforcements and at least two bow roofs. Perform draft analysis and submit section analysis report
What is Roof- In simple words Roof is the sheet metal structure which covers the top portion of a car. The main objective of providing roof is to protect the passengers of the vehicle from rain, dust, sun, wind and other external elements
Roof consists of outer panel, front roof rail, rear roof rail, and other reinforcements, sometimes roof consists of sun roof, interior lights etc.
Design considerations
- Visibility criteria
- Head clearance
- Heat distortion and snow load test
- Draft angle
- Curvature study
Visibility criteria- While designing the roof we need to consider that any part of the roof is not coming in the drivers vision.
Head Clearance- There should be proper clearance between the head of the driver and roof interior for the safety purpose
Draft Angle- while designing the roof components we need to keep draft angle in mind because the basic manufacturing process of Roof outer and inner parts is stamping and deep drawing so if we don't provide sufficient draft angle then manufacturing of the parts is very difficult and cost consuming.
Heat distortion and snow load test- We will see this later in the report
Roof Parts
Outer roof panel- this is a styling surface of the roof, which gives the aesthetic looks to a vehicle, we also provides embosses to the outer panel to imrove its strength this panel also helps with the aerodynamics of the vehicle.
Front roof rail- the front roof rail is the supporting member added to the outer panel of roof, front side of front roof rail is spot welded to the ditch area of roof because above this welded surface there is a windshield is placed to from outside this welding cannot be seen and at the back side there is a provision for mastics
Bow roof rail- Bow roof rail is just the supporting members for the roof and this usually welded at the side of the roof in the ditch area by spot welding and in middle mastic area is provided we can add bow roof on the basis of curvature of the roof and different calculations like heat distortion and snow load conditions.
Center roof rail- this is also a similar to the bow roof but it usually more in width and have more section modulus we also adds reinforcement for more strength on the center roof rail we can provide various types of mountings for lights and other purposes 
Rear Roof Rail- this rail not only support the roof outer panel but also give strength to the back door of the vehicle, back side of the rear roof rail is welded to the ditch area of the roof and we also provides the mastic provision at the front side of the rear roof rail
Section Inertia Analysis
Front Roof Rail
Front Bow Roof
Center Reinforcement rail
Rear Bow Roof
Rear Roof Rail
Heat Distortion Calculations
Snow load Calculations
Draft Analysis
Front Roof Rail
Bow Roof One
Center Roof Rail
Bow Roof Two
Rear Roof Rail
Model Images
Conclusion- This model of roof has satisfy the Heat Distortion criteria for all sections but in snow load criteria satisfy 2 out of 3 sections so we have add embosses to the outer panel