Anti-Roll Bar

I designed, manufactured, and integrated a front anti-roll bar (ARB) into Columbia's Formula SAE 2024 vehicle.

Skills developed:

  • Mechanical properties of materials

  • System and component design

  • Composites manufacturing

  • Metal machining

  • Cross-system integration

  • System validation and testing

Software utilized:

  • SolidWorks (CAD, FEA)

  • OptimumKinematics (kinematics design)

  • Autodesk Fusion 360 (CAM)

  • Motec i2 Pro (data analysis)

Tools put to use:

  • CNC mills (Haas Mini-Mill, Tormach 770M)

  • Manual lathe (Fryer Easy Turn)

  • Waterjet (Ward A-0612)

  • Instron (5569A)

  • Hand tools

The goal behind the implementation of the ARB was to partially decouple roll rates of the vehicle from the ride rates. Without an ARB, the spring constants dictated both the ride and the roll rates; introducing an ARB into the system allowed for tuning of the roll rates without changing the ride rates.

Given the desired roll gradient of 0.75 deg/g, I was able to select materials for the components comprising the system based on the their mechanical properties. I then outlined the geometry of the ARB using a suspension kinematics software Optimum Kinematics.

Steering rack clamps offered a convenient placement for the ARB mounting locations; utilizing SolidWorks, I integrated the ARB mounting into the clamps using press-fit needle bearings and shaft clamps as points of interface between the two systems.

After finalizing the design, I manufactured the components comprising the ARB. As illustrated here, I created a Fusion 360 CAM for lever arms; I then machined them on a Haas mini-mill. I also machined the twistbar on a manual lathe and a mill, manufactured the droplinks out of carbon fiber tubes by cutting them to length and bonding them to steel inserts, and waterjetted rockers and milled the mounting holes in them on a Tormach CNC mill. 

During the initial assembly I discovered a significant amount of play between the twistbar and the lever arms. This discovery led me to modify the design of the lever arms by introducing screws that were threaded into the lever arms on one side; that addition allowed for the screws to clamp down on the twistbar, eliminating the play in the system. I added lock washers and safety wired the bolts to prevent the screws from loosening from the vibrations from vehicle's motion. 

I then integrated the systems together and assembled the anti-roll bar system on the car.

I also went through multiple steps to validate the system. Prior to assembling the ARB, I tested the droplinks on an Instron machine in tension and compression in order to ensure the strength of the bond between the carbon fiber tube and steel inserts. I also validated the system performance in heave and roll by measuring static corner weights at front wheels. Finally, following the testing sessions with the ARB fully integrated into the vehicle, I was able to verify the decrease in roll gradient from the data obtained by sensors on the vehicle (on the graphs, pre-ARB (top) and post-ARB (bottom) addition histograms for roll angles (left) and lateral accelerations (right)): for a similar set of roll angles, the lateral acceleration set had an increased average after the integration of the ARB; this implies that the roll gradient decreased, confirming that the anti-roll bar likely worked as intended.