Roof challenge

Challenge 7: Roof Design

Introduction:

A roof is an important part of a car's BIW. The roof protects the passengers from a lot of conditions and they are designed based on these criteria. A roof typically consists of a front roof rail and a rear roof rail if the vehicle is small and compact. The stability of the roof is not maintained with only the front and the rear roof rails for large or big vehicles. So, bow roof rails and reinforced roof rail are designed. A reinforced rail roof is very thick and can be called as a simple bow roof. This is intentionally made thick as it is connected to the B pillar of the car. All bow roofs and the rail roofs are attached to the surface of a roof with the help of mastic points. In this Challenge, a student is expected to consider all the design criteria while designing a roof and calculate the general snow load and heat distortion criteria to determine the viability of the design. However, the design is also physically tested to gauge the impact of it to the passengers. A typical roof structure is shown below:

The following are the results of the roof designed as part of the assignment:

Front Rail:

Bow Roof 1:

Center rail/ Reinforcement Rail:

Bow Roof 2:

Rear Rail:

Following is the table showing calculations of the heat distortion criteria :

Following is the table showing calculations of the Snow Load criteria :

The snow load conditions of the roof designed in this challenge do not meet the requirements. However, this proves that the design can be improved to meet the requirements. The latter part of design engineering is meant to correct these issues.

The Section Modulus Analysis of each part is as follows:

Bow Roof 1:

Bow Roof 2/Reinforcement Roof Center:

Bow Roof 3:

Conclusions:

The part designed in this challenge gave enough understanding of the design considerations for designing a roof. Many operations were used in surface modeling to obtain the results as displayed above. A typical functioning of the firm is understood and the manufacturability issues are considered as part of designing.