Hi Darwin, Sure, you can modify the force model this way. I didn't see any obvious problem with the added code in function *computeSphereNormalForces_matbased*, apart from that in the calculation of *a_SJKR*, the *dist_SJKR²* term seems to just cancel out in the numerator and denominator, and that I'd ask you to make sure the CED_SU term is properly converted to the simulation unit before usage.
If there are scenarios where it fails and you want to debug, then a better approach is always, to start from the minimum and gradually isolate the problem. You can test if it works without the newly added cohesion force first, then go from there. Thank you, Ruochun On Wednesday, July 13, 2022 at 9:56:04 PM UTC-5 [email protected] wrote: > Hello, > > Mohammad and I are working together on this project. The custom functions > are used to pass new parameters into an updated collision model we are > using and have taken into account the unit conversion. Primarily, we are > changing the way the normal force is calculated. I'm assuming this is why > we are seeing instability from our chrono build. We've done this by simply > changing the way normal force is being calculated in the function > computeSphereNormalForces_matbased() in ChGpu_SMC.cuh. We've set > UseMaterialBasedModel as true. > > Does this methodology sound correct? We're trying to debug if our > implementation is correct, to figure out if our collision model is the main > problem. I've attached the folder. > > Thank you, > > Darwin Mick > > On Sunday, July 10, 2022 at 1:36:15 AM UTC-7 Ruochun Zhang wrote: > >> Hi Mohammad, >> >> I took a look at the script you shared and it seems that you have a >> couple of custom functions such as SetInterfacialSurfaceEnergy (which is >> why I can't build it). It is a possibility that those parameters interplay >> with existing DEM parameters so some of them become not physical on given >> settings. >> >> Other than that, I'd suggest you repeat the previous test with the >> cone_shaft_modified mesh I attached in this post to see if this works. The >> construction of that mesh should rule out the influence of mesh quality. >> You can try even smaller time step size (maybe 1e-7) in the test, although >> I feel 5e-7 that you are using is fine enough... >> >> If they still do not help, then again it's even stranger. I can try to >> debug to see if it is because of Chrono under-the-hood unit conversion, if >> I have access to a script that helps me reproduce the problem. >> >> Thank you, >> Ruochun >> >> On Saturday, July 9, 2022 at 9:09:38 PM UTC-5 [email protected] wrote: >> >>> Hello Ruochun, >>> >>> Thank you for constantly following up and answering my posts. I have >>> suppressed the tip of the cone and tried to run the simulation but I am >>> still getting exactly the same error. >>> >>> Thank you so much, >>> >>> On Friday, July 8, 2022 at 12:53:40 AM UTC-7 Ruochun Zhang wrote: >>> >>>> Hi Mohammad, >>>> >>>> Then it is quite surprising. This error means a sphere is touching 30 >>>> objects, mesh facets and other spheres included. What comes close to being >>>> the cause is still in my opinion, the tip of the mesh. I'd suggest you >>>> modify your script a bit so it represents a scenario where a cylinder is >>>> dropped (i.e. the same part, but without the tip) onto the granular bed. >>>> Run it and if it works you know the problem is the tip mesh, and I have a >>>> few ideas on how to resolve that. If that still does not work, then in the >>>> simulation at some point the physics must've gone wild somehow, and that'd >>>> take a bit more effort to find. >>>> >>>> Also, make sure you *rebuild Chrono each time* you make change to the >>>> source code, such as changing MAX_SPHERES_TOUCHED_BY_SPHERE. You can >>>> change >>>> it back to 12 or something smaller like 20 when you are doing the testing. >>>> >>>> Thank you, >>>> Ruochun >>>> >>>> On Thursday, July 7, 2022 at 11:32:39 PM UTC-5 [email protected] >>>> wrote: >>>> >>>>> Hi Ruochun, >>>>> >>>>> I have tried the solution you told me about in your post. I have >>>>> changed the *MAX_SPHERES_TOUCHED_BY_SPHERE to be 30. *However, now, I >>>>> am getting the following error (*error file: *unspecified launch >>>>> failure in ChGpu_SMC_trimesh.cu 754, *Output file:* Sphere 16054 >>>>> is touching 12 spheres already and we just found another!!!). Also, I >>>>> have >>>>> tried to change the mesh to have less slender elements near the tip >>>>> however >>>>> I still got the same error. >>>>> >>>>> Thank you so much, >>>>> On Wednesday, July 6, 2022 at 11:21:00 AM UTC-7 Mohammad Wasfi wrote: >>>>> >>>>>> Hi Freya, >>>>>> >>>>>> My coda version is 11.4. I have an intel GPU and it still works for >>>>>> me so I am not sure how the compatibility of the GPU affects the >>>>>> animation. >>>>>> >>>>>> This page should have everything you need about ParaView: 7. >>>>>> Animation — ParaView Documentation 5.10.0 documentation >>>>>> <https://docs.paraview.org/en/latest/UsersGuide/animation.html#:~:text=In%20ParaView%2C%20you%20can%20create%20animations%20by%20recording,the%20parameters%2C%20you%20can%20play%20through%20the%20animation.> >>>>>> >>>>>> In short, I do the following steps; >>>>>> 1- open my .csv files obtained from my Chrono simulation in ParaView >>>>>> ( ParaView groups all files under the one.). >>>>>> 2- right click on the files the .csv --> add filter --> >>>>>> alphabetical-->Table to points. >>>>>> 3- assign the x,y, and z columns. >>>>>> the window should have a visualization of your results ( you could >>>>>> change the representation to what you think is best under the >>>>>> representations menu). >>>>>> 4- file --> save animation. >>>>>> >>>>>> Hope this helps, >>>>>> Mohammad >>>>>> On Tuesday, July 5, 2022 at 2:42:52 AM UTC-7 [email protected] >>>>>> wrote: >>>>>> >>>>>>> Hi Mohammad, >>>>>>> >>>>>>> can I ask how you create the Chrono video with Paraview? I want to >>>>>>> create video of my Chrono example with Paraview too. Which CUDA version >>>>>>> are >>>>>>> you using ? I want to install chrono::gpu and I am trying CUDA 11.7 but >>>>>>> it >>>>>>> does not work correctly, maybe because my GPU is not CUDA compatible. >>>>>>> Perhaps later on if I have better GPU. >>>>>>> >>>>>>> Thanks for sharing the video. >>>>>>> >>>>>>> Le mar. 5 juil. 2022 à 01:28, Mohammad Wasfi <[email protected]> >>>>>>> a écrit : >>>>>>> >>>>>>>> Hi, >>>>>>>> >>>>>>>> Thank you so much for your help. I really appreciate it. I will >>>>>>>> definitely rebuild Chrono again using the latest version and will let >>>>>>>> you >>>>>>>> know if any changes occur. For the cone, I have implemented a motor >>>>>>>> that >>>>>>>> ensures a constant velocity of the cone. My understanding is that the >>>>>>>> motor >>>>>>>> applies as much force as needed to maintain a constant velocity of the >>>>>>>> cone >>>>>>>> which is the reason why the cone does not stop in the bed. I have >>>>>>>> generated >>>>>>>> another video using ParaView ( >>>>>>>> https://drive.google.com/file/d/1q-hgTcJY62kLblqr37sFoHX-4goOwbzR/view?usp=sharing) >>>>>>>> >>>>>>>> and it shows that the cone pushes the particles away as it moves. >>>>>>>> Also, non >>>>>>>> of the particles get inside the cone. I have included the .cpp file >>>>>>>> needed >>>>>>>> to run this simulation to avoid any confusion. >>>>>>>> >>>>>>>> Forgive me I had to upload the video as a link due to size >>>>>>>> limitations for the post. >>>>>>>> >>>>>>>> Thank you so much for your help and please let me know if there is >>>>>>>> anything else you want me to provide to you, >>>>>>>> >>>>>>>> Mohammad, >>>>>>>> >>>>>>>> -- >>>>>>>> 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]. >>>>>>>> To view this discussion on the web visit >>>>>>>> https://groups.google.com/d/msgid/projectchrono/6d42e6d0-d9f3-4612-b5ea-ad853ac2b082n%40googlegroups.com >>>>>>>> >>>>>>>> <https://groups.google.com/d/msgid/projectchrono/6d42e6d0-d9f3-4612-b5ea-ad853ac2b082n%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>>>>> . >>>>>>>> >>>>>>> >>>>>>> >>>>>>> -- >>>>>>> С наилучшими пожеланиями, Богиня Фрейя >>>>>>> Atenciosamente, Freya the Goddess >>>>>>> Meilleurs voeux, Freya the Goddess >>>>>>> Liebe Grüße, Freya the Goddess >>>>>>> Best wishes, Freya the Goddess >>>>>>> よろしくお願いします、Freya the Goddess >>>>>>> 最好的祝福，Freya the Goddess >>>>>>> Matakwa mema, Freya the Goddess >>>>>>> مع أطيب التمنيات ، فريا الإلهة >>>>>>> >>>>>> -- 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]. To view this discussion on the web visit https://groups.google.com/d/msgid/projectchrono/f5a38823-988e-4990-9e8a-3ecf60a20afbn%40googlegroups.com.
