Composite Suspension-Capstone

What?

• Designing a composite lower control arm for a solar car’s suspension. The part will need to handle various loading conditions as the solar car hits bumps, corners, and brakes.

• Simulations need to be performed to find critical stress concentration areas on the composite part.

• Manufacture the part with special manufacturing processes for composites.

• Test the part either in destructive or non-destrictive tests to verify the simualtion results.

How?

• Design: The design considered three possible designs and finally diverged to a sandwich panel design. Sandwich panels performed superior as the loading condition included bending; without bending tubular designs would have worked as commonly done in Formula 1 race cars as shown below.

However, with the design of the solar car’s suspension, a foam core was needed to make sure the fiber does not buckle locally and dramatically increase the second moment of inertia against bending.

The image above shows the shock absorber connected to the middle of the lower control arm, exhausting considerable force in bumps causing a three-point bend phenomenon on the control arm.

In summary the final design consisted of 8 layers of spreadtow carbon fiber with a 1” Rohacell 200 HERO in between. This design increased bending strength considerably than npn-sandwich panel designs, attachments to chassis and wheel was done through metal parts attached with epoxy adhesives. The image below shows the design in CAD.