1. SAE Baja -Brakes and Frame-
Presented by:
Don Siler
Matthew Zollars

2. Objectives / Table of Contents
BRAKES
Objective 1: Adhere to all SAE rules
Objective 2 : Locking up all 4 wheels
FRAME
Objective 3: Modify Current Frame
Objective 4: Ensure Driver Safety

3. Objective 1 – Adhere to all SAE rules
Foot-operated brake pedal
Hydraulic brake system
Hydraulic-activated brake light switches
Securely mounted brake lines
2 independent brake systems

4. Design Alternatives – Independent hydraulic circuits
Front/Rear Split
Diagonal Split (Criss-Cross)
Front system is independent from rear
More brake line is requirement – more intricate

5. Failure Mode Effects Analysis (FMEA)
Adhering to the SAE rules helps address the most serious potential failure

6. Objective 2 – Lock up all 4 wheels
All 4 wheels must simultaneously lock up
Static and movement situations
Paved and unpaved surfaces
Design changes from other teams can easily effect the ability of the brakes to lock up the wheels
Need to ensure the flexibility of the design and robustness of components
Necessary to consider dynamic weight transfer

7. Dynamic Weight Transfer
𝑭 𝒏,𝒇 = 𝒎𝒈 𝑳 ( 𝑳 𝒓 + 𝑯 𝒄𝒐𝒈 ∗𝝁)
𝑭 𝒏,𝒓 = 𝒎𝒈 𝑳 ( 𝑳 𝒇 − 𝑯 𝒄𝒐𝒈 ∗𝝁)

8. Objective 2 – Bias Bar Adjustment

9. Design Alternatives – Choice of Rear Calipers
Selected a rear differential
Necessity of 2 rear calipers
Option of re
Wilwood HM-1 Calipers

10. Selected Component Flow Chart

11. Brake Lines and Fittings – Reduce Leaking
Leaking brake lines and fittings have been a problem on the Baja
3/16” O.D. Double-wall steel tubing is the industry standard
SAE recommends Using SAE 45° inverted flare joints

12. Objective 3 – Frame Modifications
Modifying 4 secondary
members

14. Raise Purple Fore/Aft Bracings and Lateral Cross member by 4 inches
Widen Green Fore/Aft Bracing
by 5.5 inches

15. Roll Cage Calculations
Finding Bending Strength & Bending Stiffness
1018 Mild Steel
4130 Chromoly
E =
205
Gpa
OD =
0.025 m
ID =
0.0193
0.0284
t =
0.003
0.0017
Syield =
365
Mpa
460
c =
0.013
0.016
I =
1.36E-08 m4
1.79E-08

16. 1018 Mild Steel 4130 Chromoly Steel
Strength Bending = Syield ∗ I c
= 510 N-m
Strength Bending = Syield ∗ I c
= 391 N-m
Strength Bending = 510− x 100%
= 30.4 % greater

17. StiffnessBending= 3635−2791 2791 x 100%
1018 Mild Steel
4130 Chromoly Steel
Stiffness Bending = E * I
= 3635 N - m2
Stiffness Bending = E * I
= 2791 N - m2
StiffnessBending= 3635− x 100%
= 30.2 % greater

18. Objective 4 – Driver Safety
Firewall = Textured 3003 H14
Corrosive resistant
Increased rigidity from texture
Used in gasoline tanks
Cooking utensils
Tool Boxes

19. Paneling = Ultra High Molecular Weight Plastic
High Abrasion Resistance
High Chemical Resistance
High Impact Resistance
Lightweight
Used in body armor
Vehicle Skid Plates

20. Costs 2014 - 2015 Frame 2015-2016 Frame Brakes – If all new parts
Total
~$1,500
Frame
~$250
Brakes – If all new parts
Total
~$1,500
Brakes – With re-used parts
~$250

21. Conclusions
Project Management of a large (~14 team members) project is very difficult
Better project management and communication could have improved the project
Delay in getting accepted to BAJA Competition impeded progress
The brake system has few components, but some fairly involved interactions to guarantee consistent performance
Frame design is highly dependent on ALL teams’ needs

22. Conclusions Testing could not be done yet
Testing and design iteration is vital to a successful project
Recommend small BAJA team that focuses on a single vehicle subsystem

23. Questions??