The FIALA tire model provides a stepping stone in full vehicle simulation because it is simple enough to be completely understandable by the MBD analyst. Furthermore, the forces, and torques produced by the tire/road interaction use a series of physically meaningful parameters.
It is easy to obtain such parameter values for a wide variety of real tire models via straightforward measurements, and therein lays the value of this simple tire model.
On the other hand, the FIALA tire model makes a series of assumptions when computing forces and torques. These restrict its applicability only to a limited set of vehicle maneuvers that do not violate the following simplifications:
| • | Rectangular shape of the contact patch. |
| • | Force does not depend on the camber angle. |
| • | Uniform distribution of contact patch forces. |
| • | Gyroscopic torques due to the inertia of the tire carcass are neglected. However, these may be accounted for by adding the mass and inertia of the tire to the wheel. |
It is important to keep in mind that no real tire behaves as described above, therefore the applicability of the FIALA tire model is limited to primarily steady-state events, on smooth surfaces and exclusively in the domain of vehicle handling. In addition, the Altair MotionSolve FIALA implementation neglects first order lag or tire relaxation effects.
For all tire models, including FIALA, there are two sets of inputs that are considered during the computation of forces and moments:
See Also:
Force Evaluation
Smoothing
Conclusions and References
