HJ, Keep in mind that SCM is just a framework that generalizes the semi-empirical Bekker theory to arbitrary terrain topography and impactor geometry. As such, in terms of modeling a particular type of soil, you will need to look for appropriate parameter values which typically come from bevameter experiments. Look for example in the book by Wong, or any other source for such parameters.
The FEA deformable soil model in Chrono::Vehicle is not really maintained (it builds and should work, but we have not used it for any relevant simulations). That modeling approach is computationally quite expensive, relies on parameters that are difficult to come by, and (unlike granular dynamics or the CRM approach that Dan mentioned) cannot capture larger soil deformations. If you are interested in an FEA-based approach, look also at work by Yamashita and Sugyiama on hybrid FEA-DEM formulation (by the way, their terramechanics code can be coupled to Chrono vehicle simulations through the Chrono::Vehicle co-simulation framework). But I second Dan’s suggestion to look at the deformable soil formulations available in Chrono, in the order SCM, CRM, DEM. --Radu From: [email protected] <[email protected]> On Behalf Of hj Sent: Thursday, 2 March 2023 16:44 To: ProjectChrono <[email protected]> Subject: Re: [chrono] Wheeled vehicle simulation on deformable terrain? Hello Dan Thank you very much for your comprehensive reply and sending the papers. The papes are very interesting works. I will definitely go with the order that you mentioned for using different methods. I just have a couple of follow up question. What do you mean by " we don't have FEA model for terrain" ? what is the main limitation of FEADeformableterrain class ? And is there any paper you guys published for the mud modeling using SCM that I can have a look? Thank you and Regards On Wednesday, March 1, 2023 at 8:24:15 PM UTC-4 Dan Negrut wrote: Hi hj, You want to use SCM as much as possible. We used it in the past for mud and almost rigid terrain (small sinkage). It’s pretty much an empirical approach. In general, SCM can run at Real Time Factor close to 1 (that is, real time). We do not have a FEA model – the Chrono continuum terrain model is solved with SPH and it’s called Continuous Representation Model (CRM). CRM is your next fastest choice, RTF is anywhere from 50 to 200. If you go to DEM, the RTF probably is going to reach into 1000. So, if you want to generate training data and need to get tons of data, try, in this order, SCM, CRM, DEM. See here<https://asmedigitalcollection.asme.org/computationalnonlinear/article-abstract/doi/10.1115/1.4056851/1156640/Real-time-Simulation-of-Ground-Vehicles-On?redirectedFrom=fulltext>, and here<https://www.authorea.com/doi/full/10.22541/au.167355891.12085319/v1>, for recent papers on this topic. For DEM, we’ll have a paper out soon, but for an older version, see here<https://www.mdpi.com/2227-9717/9/10/1813>. Good luck. 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<tel:(608)%20772-0914> http://sbel.wisc.edu/ http://projectchrono.org/ --------------------------------------------- From: [email protected] <[email protected]> On Behalf Of hj Sent: Wednesday, March 1, 2023 2:52 PM To: ProjectChrono <[email protected]> Subject: Re: [chrono] Wheeled vehicle simulation on deformable terrain? Hi I had a question about using deformable terrain in Chrono. Maybe it's not chrono-specific but I aappreciate if I can have a feedback. I have a few research goals that I'd like to use Chrono for. Right now my work is to get data from tire (for now just tire and then the vehicle ) on deformable terrain to train RL or ML models. I started with SCM and rigid tire and my goal is to have data from different "types" of terrain such as soft and hard soil, snow, gravel, mud , etc. My question is for what type of terrain you think SCM would work the best to have the model close to real life? And for what type of terrain, I "have to" use DEM and granular terrain modeling methods? And for what type of terrian you think it's better to use FEA terrain? I appologize if my question is too long but I appreciate any feedback! Regards On Thursday, January 26, 2023 at 3:12:45 PM UTC-4 Radu Serban wrote: Yes, of course you can use wheeled vehicles on deformable terrain. There are demos in the Chrono distributions that illustrate that. Which particular deformable terrain formulation are you interested in? Finally, would you please let us know where in the tutorials is mentioned that only tracked vehicles work with deformable terrain?! --Radu From: [email protected] <[email protected]> On Behalf Of hj Sent: Thursday, 26 January 2023 19:43 To: ProjectChrono <[email protected]> Subject: [chrono] Wheeled vehicle simulation on deformable terrain? Hello I've been reading the chrono tutorial about deformable surface modeling. I was wondering if there is any way I can use Chrono for simulation of wheeled vehicle on a deformable terrain? It is mentioned in the tutorials that deformable terrain models only work with tracked vehicles! I appreciate any feedback ! Thank you -- You received this message because you are subscribed to the Google Groups "ProjectChrono" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. 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