FSAE Suspension Force Calculator

For the 2024-25 FSAE season, I developed a MATLAB suspension analysis tool to calculate suspension member loads from simulated contact patch forces. The script reconstructs the suspension geometry from OptimumK kinematics data, solves the suspension kinematics through trilateration, and computes the axial force in each suspension member by enforcing 3D static equilibrium.

The tool imports Excel files in the same output format from Optimum Kinematics, a suspension analysis program used by the team’s Vehicle Dynamics group to design suspension geometry. This Excel file is a formatted list of each inboard and outboard suspension point, which is used to calculate the length of each member for trilateration. The user can input a range and step size for steering and shock movement, and each load case from the contact patch force spreadsheet will be evaluated at each suspension position.
 The tool also imports multi-case contact patch loads from Excel, in the format output by the VD group’s custom contact patch force simulation. Load cases generated from right-side tires are reflected over the vehicle’s midplane to the left side of the car, where all further analysis and design of the vehicle is done.

After each load case is evaluated in each desired suspension position, a Load Summary is produced that details peak loads in both directions and monocoque normal/tangential loads for each member. These normal/tangential components of suspension forces on the monocoque surface are the primary design loads for the team’s chassis group.

This tool took what used to be 90-120 minutes in Mitchell’s Racing by the Numbers and turned it into 1-2 minutes of required engineering time for each instance of suspension member force calculation. This drastic reduction in time allows for rapid iteration of kinematic points to optimize loads, something the team was never previously able to do. The painstaking process of manually transcribing numbers from one sheet another was completely removed and many gray hairs along with it.