Good morning,
Thank you very much for your replies and the examples you gave me. I had to 
reinstall the entire simulator because some modules (PardisoMKL) were 
missing. Now I am able to run FEA/ANCF/Reissner models on tire test rigs.

However, the simulation is extremely slow, even when using all my CPU 
cores. I was wondering if there are any plans to implement FEA computation 
on NVIDIA GPUs in the future.
For now, I will stick with rigid tires, since the simulation time is close 
to real time and works well when the terrain is softer than the tire.

I noticed that several rigid tires are available, such as 
HMMWV_RigidMeshTire_CoarseClosed, HMMWV_RigidMeshTire_Coarse, 
HMMWV_RigidMeshTire, and HMMWV_RigidTire. Could you please explain the 
differences between them?

Thank you for your help! 😊
Le mercredi 6 août 2025 à 13:02:40 UTC+2, Radu Serban a écrit :

> Some clarifications and comments:
>
>  
>
> You are correct. As indicated in the documentation, handling tire models 
> (aka force-element) tire models cannot be used with deformable terrain.
>
> For that, you need a tire model that carries collision shapes. That can be 
> an FEA-based tire model or, as already pointed out, a rigid tire model.  
> The latter is appropriate in soft soils (when the soil strength is below 
> the tire inflation pressure).
>
>  
>
> So, you should first decide if you indeed need flexible tires or if a 
> rigid tire model will be good enough. Not that, should you use an FEA tire 
> model, you also need to come up with appropriate parameters for the tire 
> geometry and materials, data that is not easily obtainable.
>
>  
>
> If you stick with FEA (ANCF) tires, whether you use the SCM terrain (as 
> you first intended) or the CRM terrain (as Dan suggested), the bottleneck 
> will be the FEA calculation. The computationally cost will be that much 
> higher if you simulate all tires on a single node. I do not see any crashes 
> with demo_VEH_SCMTerrain_WheeledVehicle if I switch the tire model to an 
> FEA-based one, but simulation is indeed very slow.  Note that the code that 
> Ganesh shared with you also uses a single CPU node to simulate all 4 tires. 
> That simulation ran about 500 times slower than real time (on a relatively 
> potent CPU).
>
>  
>
> The solution to this is to use the vehicle co-simulation framework 
> <https://github.com/projectchrono/chrono/tree/main/src/chrono_vehicle/cosim> 
> which would allow you to run individual tires on their own node. Of course, 
> to really benefit from that, you now need access to a cluster.  Note that I 
> am aware of an issue with the co-simulation code when using FEA tires and 
> CRM terrain which I plan on looking at soon. I don’t know if that same 
> issue shows up when using SCM terrain and FEA tires.
>
>  
>
> We’ll also make some changes to the HHT integrator that will help with 
> performance of integrating large FEA problems. That should also come in 
> Chrono in the near future.
>
>  
>
> --Radu
>
>  
>
>  
>
>  
>
> *From:* [email protected] <[email protected]> *On 
> Behalf Of *juju
>
>
> *Sent:* Friday, August 1, 2025 3:05 PM
> *To:* ProjectChrono <[email protected]>
>
> *Subject:* Re: [chrono] HMMWV with ANCF tire
>
>  
>
> Hello,
>
> I would like to study the interactions between a tire and various terrain 
> obstacles while the vehicle is in motion. I saw that several tire models 
> are available, such as TMeasy, Pacejka02, ANCF, and Reissner.
>
> According to the documentation, force-based tire models (e.g., Pac02, 
> TMeasy) cannot be used with soft obstacles or deformable terrain (such as 
> sand, snow, or grass). On the other hand, the ANCF tire model is 
> specifically designed to accurately capture soil–tire interactions.
>
> Therefore, for my use case, the ANCF tire model seems to be the most 
> appropriate choice.
>
> I tried using it with the demo script 
> demo_VEH_SCMTerrain_WheeledVehicle.cpp, but after just a few milliseconds 
> of simulation, the tire explodes, and the simulation is extremely slow 
> (even with SetNumThreads set to the maximum number of available threads).
>
> I’m wondering if anyone has successfully run the ANCF tire model with the 
> HMMWV (or other vehicles) in a simulation that utilizes hardware resources 
> efficiently (CPU, GPU, etc.).
>
> Thank you for your help! 😊
>
>  
>
> Le jeudi 31 juillet 2025 à 19:43:55 UTC+2, Dan Negrut a écrit :
>
> Hi there - can you please describe what you try to accomplish?
>
> We might be able to help with the ANCF tire model, but before that, please 
> tell us what you want to accomplish since there might be easier paths 
> forward. ANCF is heavy duty.
>
> Dan
>
> ---------------------------------------------
>
> Bernard A. and Frances M. Weideman Professor
>
> NVIDIA CUDA Fellow
>
> Department of Mechanical Engineering
>
> Department of Computer Science
>
> University of Wisconsin - Madison
>
> 4150ME, 1513 University Avenue
>
> Madison, WI 53706-1572
>
> 608 772 0914 <(608)%20772-0914>
>
> http://sbel.wisc.edu/
>
> http://projectchrono.org/ 
> <https://urldefense.com/v3/__http:/projectchrono.org/__;!!Mak6IKo!MOF05q2wXkkfBDHMnzYQlr8F1XTyRnV9WN2zouxf4gzBc2kCjT162b9jv-2okTnEQyt42oYsuhHiLTd7$>
>  
>
> ---------------------------------------------
>
>  
>
> *From:* [email protected] <[email protected]> *On 
> Behalf Of *juju
> *Sent:* Thursday, July 31, 2025 11:41 AM
> *To:* ProjectChrono <[email protected]>
> *Subject:* [chrono] HMMWV with ANCF tire
>
>  
>
> Good morning,
>
> I am a PhD student working on off-road vehicle navigation, and I found 
> ProjectChrono very interesting for testing my algorithms.
>
> I would like to use the HMMWV vehicle with ANCF tires for more realistic 
> behavior. However, when I run the demo script 
> demo_VEH_SCMTerrain_WheeledVehicle.cpp with TireType::FEA, the simulation 
> becomes unstable and extremely slow. It runs fine with other tire types.
>
> Does anyone have a demo script using HMMWV with ANCF tires that is both 
> stable and performs well (accelerated and reliable)?
>
> Thank you very much!
>
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