I am looking for a longitudinal excitation methodology(at contact patch) in Adams Car at vehicle level.Since GAA can excite only at the wheel center I am not able to use it,more over I am using a displacement function to excite the pads.I have tried to change the vertical test rig pad transnational joint orientation to horizontal,simulation is working fine but I am not able to get the expected behavior.Can anyone suggest how to do the same.
What tire model are you planning to use that is accurate for standing still tire?
I usually use the GAA with a longitudinal force and a braking/driving torque at the wheel center. f you have varying normal load and therefore varying tire radius, you can always take that into account when calculating the torque.
I am using a physically tested and validated pac 2002 tire. Tyre to Pad interaction and some of the corresponding frequencies I need to find in the dynamic condition, this is the aim. GAA will not allow me to use this approach I guess.
Jesper: if you are saying drive torque balances longitudinal force times loaded radius: this is not true. It balances longitudinal force times effective rolling radius, and only in steady-state conditions.
Tinu: Pac2002 (just like all MF-based tire models) is slip-based and, even if putting out *some* kind forces, has no sound physical basis for non-rolling wheels.
Michael, JSlatten I have created a new longitudinal four poster testrig and results are pretty matching with the test data now, as mentioned earlier I have used Pac tire only . Thanks for the valuable suggestions.