ROOF DESIGN

 

Hi colleagues,

 

 

We are dealing with the Roof design in this challenge.

 

 

OBJECTIVE AND INTRODUCTION

 

 

As requested in the Challenge for Roof Design I have to design Roof with necessary reinforcements (Master Sections for Front Roof,Rear Roof Rail,Bow Roof,Center Reinforcement Rail,Center Roof with Sun Roof ).On the Input Roof basis I have the decide about number of Roof bows,their position and jointing type.

Roof is an integral part of BIW that had function to give security for passengers regarding outside weather conditions (rain,sun,wind,snow...).With Roof parts of the vehicle are connected,it has a great,thin surface and therefore special care should be given to design appropriate reinforcements and positions of it.

Nowadays vehicles carosery is done as a monocoque BIW (BIW is done as a single caroserie frame) and Roof design has a great part regarding various external loads,reducing weight and in economical manufacturing.

 

Designing of Roof bows should be done regarding the given master sections.

 

Front Roof Rail Master section

 

Rear Roof Rail Master section

 

Bow Roof Master section 

 

Center Reinforcement Rail Master section

 

That is an Objective of Roof design challenge.

 

- Car roof with reinforcements

 

 

- Car roof with sun roof integrated

 

 

 

ROOF DESIGN PRINCIPLES

 

 

Now,quick introduction about Roof and requirements of it. Afterwards I have to do draft analysis on designed parts,Bow-Roof Prediction Formula and Snow Load Prediction Formula on designed Roof assembly.Regarding curvature analysis of the parts this is one of major criteria for resolving Roof’s possibility to withstand various loads and impacts.On the Bow’s ends flanges should be done to be able to do a proper welding Roof parts to vehicle body parts.Great attention should be given to possibility to manufacture so curvated part that had embosses.Afterwards it should be possible to weld all the parts together and to apply mastic during parts joining.

Visibility criteria at the front should be obeyed and fulfilled.

 

Apart of design requirements following master sections there are manufacturing requirements that should be fulfilled regarding manufacturability of the parts,rollover and bending,tool opening angle (7deg),curvature radius of 3mm etc.

Thickness of the Roof’s parts is 0.75mm.

 

 

 

So,following the rules to design and manufacturability I have constructed Roof design parts integrated in Roof assembly as shown on images bellow.

 

ROOF BODY PARTS REGARDING MASTER SECTIONS

 

 

FRONT ROOF RAIL – GEOMETRICAL CHARACTERISTIC 

 

I have conducted draft analysis as shown,first for Front Roof Rail.

 

 

REAR ROOF RAIL – GEOMETRICAL CHARACTERISTIC 

 

 

Draft analysis for Rear Roof Rail.

 

 

BOW ROOF RAIL FRONT – GEOMETRICAL CHARACTERISTIC

 

Draft analysis for Bow Roof Rail Front.

 

 

CENTER REINFORCEMENT RAIL – GEOMETRICAL CHARACTERISTIC

 

Draft analysis for Center Reinforcement Rail.

 

 

CENTER ROOF RAIL WITH SUN ROOF RAIL – GEOMETRICAL CHARACTERISTIC

 

 

Draft analysis for Center Roof Rail with Sun Roof Rail.

 

Final sections of Roof and reinforcements are shown bellow.I have done Roof design following rules of master section and I have add embosses to increase parts stiffenes.Higher cross section leads to higher moment of inertia that increase withstand of the parts.

 

 

 

HEAT DISTORTION CRITERIA

 

Furthermore we have to determine Heat distortion criteria in order to see if Roof can pass the applied force on the elevated temperature.Roof should endure constant applied force on it during various and higher temperatures.When the force is removed Roof  should go back to your initial state or position.

 

 

 

SNOW LOAD CRITERIA

 

Apart of Heat distortion criteria we should conduct Snow load criteria as well.So,basicaly on the top of the Roof is applied static force that determines snow weight,after constant pressure during some time force is removed and Roof should go back to its initial states without visible deflects.

 

 

CONCLUSION

 

 

At the end as a conclusion it could be said, we have dessigned Roof design with its parts taking in consideration visibility study,manufacturability (rollover and bending the parts),draft analysis and possilbility to join all the parts in one functional car part that can withstand various external conditions and impacts including fullfiling Heat distortion criteria and Snow load condition criteria.

 

 

Thank you for valuable lesson and time taken to read this article.

 

 

 

Best regards.