Fiala Tire
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.
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 to vehicle handling on smooth road surfaces.
There are two versions of Fiala in MotionSolve; one with only steady state force calculation and the other
implements the tire relaxation effects. The model is chosen based on the
“property_file_format” attribute in tire property file.
- Fiala with steady state forces. To use this version of FIALA the tire property file
should contain the following attribute:
- property_file_format = ‘FIALA’
- Fiala with tire relaxation effects. To use this version the property file should
contain the following attributes:
- property_file_format = ‘USER’
- function_name = 'mbdtire::USER_FIALA'
- RLENX and RLENY in [PARAMETER] block