Fiala contact parameter estimation

Karthikeyan

I would like to understand how to estimate the Fiala cam contact parameters PAE, PBE, PCE and PLS. What kind of test data should be requested to the tire supplier and how to estimate these values based on test data. I could find the following snippets from help documentation but they don't go into details. Thanks!

Regards

Karthikeyan

GTT Adam

Hi @Karthikeyan,

Tire suppliers may sometimes provide those values, but typically you must have the tire tested at a proper facility to produce the desired tire model. Tire testing facilities like Calspan can produce the FIALA model from a physical tire or can sometimes provide one from a known database.

Depending on the simulation, you may be able to modify a default tire model from the MotionView installation directory to suit your needs. This would mainly be for simulations early on in the design process where the most accurate representation of the tire may not be needed just yet. Alternatively, this approximated solution can be used if you are completing slower obstacle events and not high speed half-rounds, for example.

Hope this helps!

Adam Reid

GTT Adam

Hi @Karthikeyan,

The parameters you listed pertain to contact models, so a drum-cleat test is likely required. Based on the description, I would assume that a high-speed camera and drum-cleat setup is used to post-process the carcass shape through the obstacle interaction to calculate PAE and PBE.

It should be noted that these parameters are used for a 'simplified durability tire'. Therefore, the end-goal of this tire model should be heavily considered:

• If you are looking to use this model for NVH/Ride/Durability calculations, then a simplified model may not be the most suitable. Other models like FTire and CDTire (which require tire testing facilities) will be more appropriate.
• If you are looking to use this model for steady state handling and light obstacle interaction, then using the contact parameters from a similar sized tire from the installation directory would be suitable.

Hope this helps!

Adam Reid

GTT Adam

Hi @Karthikeyan,

Tire suppliers may sometimes provide those values, but typically you must have the tire tested at a proper facility to produce the desired tire model. Tire testing facilities like Calspan can produce the FIALA model from a physical tire or can sometimes provide one from a known database.

Depending on the simulation, you may be able to modify a default tire model from the MotionView installation directory to suit your needs. This would mainly be for simulations early on in the design process where the most accurate representation of the tire may not be needed just yet. Alternatively, this approximated solution can be used if you are completing slower obstacle events and not high speed half-rounds, for example.

Hope this helps!

Adam Reid

Karthikeyan

Adam, can these Fiala contact parameters be extracted by typical tire test machines by default? Are there specific test definitions that are used for these parameter extraction?

Also, when you mean "Depending on the simulation, you may be able to modify a default tire model from the MotionView installation directory to suit your needs" - we can use the contact parameters of default tire models as surrogate? Like are these parameters kind of similar for similar tire sizes?

GTT Adam

Hi @Karthikeyan,

The parameters you listed pertain to contact models, so a drum-cleat test is likely required. Based on the description, I would assume that a high-speed camera and drum-cleat setup is used to post-process the carcass shape through the obstacle interaction to calculate PAE and PBE.

It should be noted that these parameters are used for a 'simplified durability tire'. Therefore, the end-goal of this tire model should be heavily considered:

• If you are looking to use this model for NVH/Ride/Durability calculations, then a simplified model may not be the most suitable. Other models like FTire and CDTire (which require tire testing facilities) will be more appropriate.
• If you are looking to use this model for steady state handling and light obstacle interaction, then using the contact parameters from a similar sized tire from the installation directory would be suitable.

Hope this helps!

Adam Reid

Karthikeyan

Thanks for the clarification!