3D_ENVELOPING contact method

Luca Cavagna

Hello

quick doubt regarding option 3D_ENVELOPING for fiala tires.

On the manual I see 

so it seems like PAE and PBE have been scaled by ro. 

However from the table of description of the parameters it seems they are simply length

 

Also, I tried to search for some example and I can find some fiala*.tpf files (is it same as .tir or do they imply some differences?).

In the files extra parameters appear for tire footprint width PB1, PB2:

 

 

Anyone can help me with understanding? PA1, PA2 are function of deflection/radius but what for PB1 and PB2? same?

GTT Adam

Hi Luca,

I'm reposting our offline resolution here for community awareness:

 

The contact coefficients for the FIALA tire model currently require the definition of PA1, PA2, PB1, and PB2. They are listed as coefficients used for contact length and contact width for the 3D_ENVELOPING option. The calculation for contact length using PA1 and PA2 is shown in the documentation, however the calculation for PB1 and PB2 variables are not shown in any calculations. They are currently required as inputs to the tire property file or the simulation will not initialize as checks are still conducted for these parameters before the simulation starts.

However, the contact width was simplified in recent releases as this tire model is best suited for non-handling and durability events. For increased computational efficiency, the calculation was reduced to b = w / 2 and PB1 and PB2 are unused. This is what is reflected in the solver documentation.

Development has confirmed that the checks for PB1 and PB2 will be removed in future releases. 

 

Hope this helps!

Adam Reid