1. SAE BAJA 2012® Tilak Tracers

2. Introduction
The objective of SAE BAJA since the time of its inception has been to give engineering students an opportunity and a platform to absorb real time design/manufacturing experience as well as face the challenges that come along.
We at team Tilak Tracers aim to capture the title while following the various rules put forth by the SAE.

3. The car
The car design was appreciated and approved by all the senior members of the team. Ergonomics and aesthetics were taken into consideration to shape the SRP (Seat Reference Point). The HRP (Heel Reference Point) was also fixed and Higher Reference Points were designed.

4. Roll Cage
A roll cage is a specially constructed frame built to protect the occupants of a vehicle by providing a minimal three dimensional space surrounding them.
Design Objectives:
Conform to SAE Standards
Allow easy entry/exit for the driver
Ensure driver safety
Provide comfort and easy access to internals
Be feasible for mass production
Dimensions:
Total Length: 2495mm
Total Height: 1470mm + 253mm [Tyre]
Total Width: 1423mm

5. Sub Teams Tilak Tracers FEA & DFMEA Resource Sponsorship Compassing
Engine
&
Transmission
Brakes
Suspensions
FEA
&
DFMEA
Management
Steering
Safety
Innovation
Aesthetics
&
Ergonomics
Sponsorship
Resource
Compassing

6. Brakes and Suspension Front Lower and Upper Wishbone Rear Wishbone
Front Suspension
Rear Suspension

7. Steering
The Ackerman Steering system has been chosen for the car since it requires a lower steering ratio as compared to other setups
As per design, the wheelbase is 1796mm the track being 1400mm and the wheel width being 165mm. A turning radius of 2927mm was determined by using Ackerman calculations.
Also the turning angles for the inside and the outside wheels was calculated as 52° and 55° respectively.
The steering box ratio is to be as taken 15:1.
The lengths of the rack & tie rod are 18” and 10” respectively.
The Lateral force on the tyres is N = 384lbs and the vertical load is 600lbs which give the following values –
Cornering Stiffness = 100lb/degree
Tyre size designation = C
Camber angle = 0.44°
Castor angle = 5°(-ve)
Toe-in angle = 2°

8. Braking System and Circuit
Taking a total braking force+ of N and deceleration of ‘0.6g’ developed in a response buildup time of with a slip of 20%.
The Inner effective radius to be taken as 180mm and Outer effective radius as 250mm.
Effective(torque) radius calculated to be 108.5mm & braking force distribution by the circuit taken as 34:66 according to weight distribution, we get the braking distance to be 3.69mts and stopping time to be 2.44secs.

9. Engine and Transmission

10. Go Green!
By using LED Arrays for Headlamps and Tail lamps as they have:
Longer life
Greener Footprint
Lower Temperature
Shorter Buildup Time
By using incombustible and non-fuming green sheet insulation for:
Isolation of the battery compartment from engine heat
This protects the battery and allows for closer placement to the engine which helps avoid starting issues arising from excessive potential drop due to lengthy cabling
Padding the roll cage around the driver’s head and Insulating the driver/engine compartment
In the case of a fire emergency, the fiber padding used on the roll cage for driver safety can combust rapidly resulting in the production of fumes which are not only polluting but can also suffocate the driver. Green insulation ensures this does not happen since it swells on igniting but does not combust.
By using Paper Honeycomb material for the Seat and as a sheet metal replacement
In an attempt to save on fiber, metal and other products we have decided to use paper honeycomb material as the core substance for the sheet metal replacement that will be used in the body panel and seat .
Paper Honeycomb as the name suggests uses RECYCLED PAPER for the buildup of the core material

11. Going Green! Green , Incombustible AEROFLEX EPDM insulation.
Paper Honeycomb
Green , Incombustible AEROFLEX EPDM insulation.

12. DFMEA 1)Roll Cage Prototype 2) Suspension 3) Wheel size
Triangulations were introduced , support and bracing members were redressed.
Weight and CG points were taken into considerations and suitable changes were made in the design.
Also , the members which were the weakest & vulnerable to failure during impact were fixed up.
Suspension design was changed according to finer details taken up and & calculation that varied accordingly.
Also , the wheel size earlier taken to be 14” was changed to 12” to avoid imbalance of CG and hence a better stability and control over turns.

13. 4)Roll cage design changes
1st model simply adhering to roll cage rules.
2nd model comprising of members for rear suspension were added.
3rd model , in which weak SIM members were modified.

14. FEA Stress due to side impact Front Impact Analysis of Frame
ANSYS Model of Frame
Rear impact Analysis of Frame
Wishbone Load
Rollover Analysis
Wishbone Stress Test

15. Production Planning -

16. Estimated Cost

17. Ergonomics
Vehicle safety is not just about driving well and avoiding accidents, a good driving position can make a big difference to health.
Driver ergonomics focuses on the healthy aspects of driving drawing upon biology, psychology, engineering and design to create vehicle environments in which people have a lower chance of injury.
Ergonomics aids - 1) Sitting comfortably , 2) protecting the neck , 3) Positioning the steering wheel , 4) Aiding vision , 5) Driving position and comfort .

18. Innovations
Gear Locking System