Validation of Suspension Link Loads

In Formula SAE, reducing a car’s weight and having sufficient stiffness are major factors when trying to rise above the competition at events. In previous years for the Cal Poly Racing Formula SAE team, the heaviest car subsystem had been the suspension. So for the 2015-2016 season, a senior project team focused on the design of boxed steel uprights. The team has had a load calculator that models the car through a 1.6 g turn; however, it was decided to actually gather strain measurements to back up the force measurements. This would validate the load calculator and ensure the senior project team was designing under realistic loading conditions.

Micro-Measurements Tee Rosette strain gages were bonded to the 4130 steel round tubing of the suspension links. The team wanted to use a half bridge to ensure temperature compensation for measuring axial loads; using the Tee Rosettes minimized the amount of strain gages that needed to be bonded, thus reducing the number of errors that could arise. Wire lengths were determined on the car and soldered on, but the suspension components were then removed to bring to the Instron for tensile loading. The team used an Instron to build a calibration curve that was linear within the desired range of expected loading. The components were then reinstalled for testing at the Buttonwillow Raceway Kart Track.

With the data gathered from the previous year’s car that went to competition, the team felt confident that its designs would be ready to meet the rigorous tests of Formula SAE Michigan and Lincoln events in 2016.

Click here to read the full Case Study: Validation of Suspension Link Loads for Formula SAE Race Car Design.

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