Hi everyone,

I am a current member of the suspension team on Michigan Tech's formula SAE team, and I have been working to complete an Altair MotionView Model of our vehicle's front and rear suspension. The purpose of the model is to predict load cases in different linkages in order to perform more accurate FEA, as well as how the suspension reacts under jounce and rebound scenarios.

While our team has a good idea what most of the inputs for the program should be in order to get static load results, we are wondering if anyone has any advice on what to enter for translational/rotational stiffness values [N/mm & N*mm/rad] for the joints in the model (rod ends: https://www.mcmaster.com/#60645k12/=1a3jwbz). Based on some feedback I've gotten, my idea was to model the translational stiffness as a value in the ballpark of 1e5 N/mm; does anyone have any advice on what to model as the rotational stiffness? I would think we would want to model it as something much lower since the rod ends are free to rotate to a point. I've tried finding sources online, and I've called to the supplier and McMasterCarr but neither of them are able to supply this value.

My concern is that if the rotational/translational stiffnesses are wrong, then the force predictions by model could be inaccurate as well. Any input and/or advice is appreciated.

Thanks guys!