Hi Ruochun, Thank you for your reply! Could you tell us about the data format of the input xyz generated by the HCPSampler?
Thank you, Weigang On Monday, July 1, 2024 at 4:37:11 PM UTC+8 Ruochun Zhang wrote: > You can *SetVel *to simulation entities, such as particles, before the > simulation starts. You can for example see how it is used at line 150 of > *DEMdemo_GRCPrep_Part1*. > > Thank you, > Ruochun > > On Thursday, June 27, 2024 at 3:03:00 PM UTC+8 [email protected] wrote: > >> You are right. In fact, the scenario i would like to model is that the >> impact of a rock block onto a palte after a freefall. I would like to set a >> initial velocity for the rock block according to the freefall height. So, >> how to set a initial velocity? >> >> Thank you, >> Weigang >> >> On Thursday, June 27, 2024 at 12:54:00 PM UTC+8 Ruochun Zhang wrote: >> >>> That depends on whether we are on the same page about the concept of >>> prescribing velocity. You understand that when the particles come in >>> contact with the plate, they cannot keep whatever velocity you assigned >>> them before, if you respect the contact force. So you either respect the >>> contact force or do not respect it. By assigning a prescribed velocity to a >>> family, you choose not to respect the contact force's influence on the >>> entities, and always enforce this velocity. >>> >>> What I understand that you wish to achieve is to ensure the particles >>> have a certain velocity at the moment they come in contact with the plate. >>> That is not a velocity prescription. That can instead be done in some other >>> ways. For example, initialize the simulation such that the particles are >>> touching the plate, and give the particles an initial velocity then start >>> the simulation. But I don't know if I understand what you wanted to do >>> correctly, >>> >>> Thank you, >>> Ruochun >>> >>> On Thursday, June 27, 2024 at 11:14:42 AM UTC+8 [email protected] >>> wrote: >>> >>>> Hi Ruochun, >>>> >>>> After removing the line which prescribe the linear motion, the >>>> particles can contact with the plate. However, if we have to prescribe a >>>> velocity for the particles, where should we add this line? >>>> >>>> Thank you, >>>> Weigang >>>> >>>> On Friday, June 21, 2024 at 3:12:06 PM UTC+8 Ruochun Zhang wrote: >>>> >>>>> Hi Weigang, >>>>> >>>>> This is because you prescribed the linear motion of family 1 (which is >>>>> for all the particles) to be -1.0. When the velocity is prescribed, the >>>>> simulation entities won't accept the influence of physical contacts, and >>>>> will keep the prescribed velocity no matter what. This is exactly what we >>>>> see in the simulation. Removing that line should fix it. You probably >>>>> meant >>>>> to add an initial velocity. >>>>> >>>>> Ruochun >>>>> >>>>> >>>>> >>>>> On Friday, June 21, 2024 at 9:05:11 AM UTC+8 [email protected] >>>>> wrote: >>>>> >>>>>> Hi Ruochun: >>>>>> >>>>>> The script is attached below. >>>>>> >>>>>> Thank you, >>>>>> Weigang >>>>>> >>>>>> On Thursday, June 20, 2024 at 7:27:35 PM UTC+8 Ruochun Zhang wrote: >>>>>> >>>>>>> I assume you are doing it via a custom force model. In that case, >>>>>>> this problem is very similar to the exact demo we provided (which >>>>>>> runs). >>>>>>> You have to tell us what you changed in order for us to give >>>>>>> suggestions. >>>>>>> >>>>>>> Thank you, >>>>>>> Ruochun >>>>>>> >>>>>>> On Thursday, June 20, 2024 at 6:55:10 PM UTC+8 [email protected] >>>>>>> wrote: >>>>>>> >>>>>>>> Hi Ruochun, >>>>>>>> >>>>>>>> I am currently modelling the impact of a rock block against a >>>>>>>> plate. However, as shown below, the spheres penetrate through the >>>>>>>> plate >>>>>>>> without any contact with the plate. Could you give some suggestions? >>>>>>>> [image: 微信图片_20240620185350.jpg] >>>>>>>> >>>>>>>> Thank you, >>>>>>>> Weigang >>>>>>>> >>>>>>>> On Thursday, June 20, 2024 at 5:02:38 PM UTC+8 Ruochun Zhang wrote: >>>>>>>> >>>>>>>>> Hi Weigang, >>>>>>>>> >>>>>>>>> Yes. And that's exactly what we did in the fracture demo to begin >>>>>>>>> with, is it not? >>>>>>>>> >>>>>>>>> Thank you, >>>>>>>>> Ruochun >>>>>>>>> >>>>>>>>> On Thursday, June 20, 2024 at 3:07:07 PM UTC+8 [email protected] >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> Hi Ruochun, >>>>>>>>>> >>>>>>>>>> Do you mean that we can add a if statements in the >>>>>>>>>> ForceModelWithFracture.cu to differentiate types of contacts? >>>>>>>>>> >>>>>>>>>> Thank you, >>>>>>>>>> Weigang >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> On Thursday, June 13, 2024 at 8:30:45 PM UTC+8 Ruochun Zhang >>>>>>>>>> wrote: >>>>>>>>>> >>>>>>>>>>> Currently, DEM-Engine custom model functionality permits only >>>>>>>>>>> one script, meaning that in principal, you are writing a unified >>>>>>>>>>> force >>>>>>>>>>> model that goes for sphere-sphere, sphere-boundary, *and >>>>>>>>>>> *sphere-mesh. >>>>>>>>>>> Just think of the sphere-compressor contact as a special case, >>>>>>>>>>> which is the >>>>>>>>>>> contact between a normal sphere and an infinitely-large sphere. >>>>>>>>>>> >>>>>>>>>>> About enforcing different models for different objects, you can >>>>>>>>>>> associate different objects with respective family numbers, then >>>>>>>>>>> use if >>>>>>>>>>> statements to differentiate types of contacts. I talked about this >>>>>>>>>>> in one >>>>>>>>>>> of the earlier replies in this thread, please go back and have a >>>>>>>>>>> look. >>>>>>>>>>> >>>>>>>>>>> Thank you, >>>>>>>>>>> Ruochun >>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> On Thursday, June 13, 2024 at 1:31:37 PM UTC+8 >>>>>>>>>>> [email protected] wrote: >>>>>>>>>>> >>>>>>>>>>>> Hi Ruochun, >>>>>>>>>>>> >>>>>>>>>>>> Thank you for your reply. In fact, I am puzzled that there is >>>>>>>>>>>> not any sentence in the Fracture-Box demo to declare the contact >>>>>>>>>>>> model >>>>>>>>>>>> between spheres and the compressing plate. So, how to declare the >>>>>>>>>>>> contact >>>>>>>>>>>> model, especially for the case in which there has been another >>>>>>>>>>>> contact >>>>>>>>>>>> model, such as the ForceModelWithFracture.cu? >>>>>>>>>>>> >>>>>>>>>>>> Thank you, >>>>>>>>>>>> Weigang >>>>>>>>>>>> >>>>>>>>>>>> On Thursday, June 13, 2024 at 12:03:52 AM UTC+8 Ruochun Zhang >>>>>>>>>>>> wrote: >>>>>>>>>>>> >>>>>>>>>>>>> Hi Weigang, >>>>>>>>>>>>> >>>>>>>>>>>>> Note that in general, if you use a custom force model, then >>>>>>>>>>>>> that model alone is used, there is no fallback so I wouldn't call >>>>>>>>>>>>> that >>>>>>>>>>>>> anything has "defaulted" to Hertz–Mindlin. Specific to the >>>>>>>>>>>>> Fracture-Box >>>>>>>>>>>>> demo, it's just that the force model (ForceModelWithFracture.cu) >>>>>>>>>>>>> is written >>>>>>>>>>>>> in a way that when the bond between two particles breaks, the >>>>>>>>>>>>> "else" branch >>>>>>>>>>>>> of that big if statement is executed, and something similar to >>>>>>>>>>>>> Hertz–Mindlin is enforced. >>>>>>>>>>>>> >>>>>>>>>>>>> I said it's similar since it's not a pure spring–damper model >>>>>>>>>>>>> now, it's a spring–damper model with the resting location >>>>>>>>>>>>> (zero-force >>>>>>>>>>>>> location) being the penetration depth the moment when the bond >>>>>>>>>>>>> broke. This >>>>>>>>>>>>> implementation avoids a potential problem with a pure >>>>>>>>>>>>> spring–damper model: >>>>>>>>>>>>> Without the adjusted resting location, a newly broken-away pair >>>>>>>>>>>>> of >>>>>>>>>>>>> particles would see the bond suddenly gone but there were still >>>>>>>>>>>>> left-over >>>>>>>>>>>>> penetration, therefore immediately pushing each other away with >>>>>>>>>>>>> high >>>>>>>>>>>>> velocity, resulting in non-physical results. Shout-out to Bona >>>>>>>>>>>>> for >>>>>>>>>>>>> implementing this. >>>>>>>>>>>>> >>>>>>>>>>>>> Thank you! >>>>>>>>>>>>> Ruochun >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> On Wednesday, June 12, 2024 at 8:33:55 PM UTC+8 >>>>>>>>>>>>> [email protected] wrote: >>>>>>>>>>>>> >>>>>>>>>>>>>> Hi Ruochun, >>>>>>>>>>>>>> >>>>>>>>>>>>>> Thank you for your great work. The demo now is runs well. I >>>>>>>>>>>>>> have a question about the Fracture-Box demo. After the bond >>>>>>>>>>>>>> between two >>>>>>>>>>>>>> particles breaks, is it right that the contact model between >>>>>>>>>>>>>> them change >>>>>>>>>>>>>> defaultly from ForceModelWithFracture to Hertz–Mindlin model? >>>>>>>>>>>>>> >>>>>>>>>>>>>> Thank you, >>>>>>>>>>>>>> Weigang >>>>>>>>>>>>>> >>>>>>>>>>>>>> On Friday, May 31, 2024 at 8:05:24 PM UTC+8 Ruochun Zhang >>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>> >>>>>>>>>>>>>>> Hi Weigang, >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> The problem appears to be fixed now. Please pull the newest >>>>>>>>>>>>>>> main branch and try the fracture demo again. I suggest you do a >>>>>>>>>>>>>>> clean >>>>>>>>>>>>>>> rebuild from an empty directory, because only a force model >>>>>>>>>>>>>>> file is changed >>>>>>>>>>>>>>> and if you just "make", cmake probably thinks nothing needs to >>>>>>>>>>>>>>> be done. Or >>>>>>>>>>>>>>> you can simply manually copy the modified cu file over to the >>>>>>>>>>>>>>> appropriate >>>>>>>>>>>>>>> location in the build folder. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> The problem was that we left an uninitialized variable in >>>>>>>>>>>>>>> the force model file. On data center cards, the compiler zeros >>>>>>>>>>>>>>> it out >>>>>>>>>>>>>>> automatically, but on consumer cards it does not. We therefore >>>>>>>>>>>>>>> missed it >>>>>>>>>>>>>>> initially. Should be all good now. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Thank you, >>>>>>>>>>>>>>> Ruochun >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> On Tue, May 28, 2024, 11:00 PM Ruochun Zhang < >>>>>>>>>>>>>>> [email protected]> wrote: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> Hi Weigang, >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> It's not like recommending a card; rather, if you happen to >>>>>>>>>>>>>>>> have a data center card available (A100, A5000 etc.), you can >>>>>>>>>>>>>>>> circumvent >>>>>>>>>>>>>>>> this problem for now by using them. Otherwise, let's hope we >>>>>>>>>>>>>>>> find a >>>>>>>>>>>>>>>> solution very soon, or at least find a workaround. We'll keep >>>>>>>>>>>>>>>> you posted. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> Thank you, >>>>>>>>>>>>>>>> Ruochun >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> On Monday, May 27, 2024 at 7:27:10 PM UTC+8 >>>>>>>>>>>>>>>> [email protected] wrote: >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> Hi Ruochun, >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> My card is indeed a gaming card NVIDIA GeForce RTX 2070 >>>>>>>>>>>>>>>>> Super. Could you recommend a card? >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> Thanks, >>>>>>>>>>>>>>>>> Weigang >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> On Saturday, May 25, 2024 at 10:44:17 PM UTC+8 Ruochun >>>>>>>>>>>>>>>>> Zhang wrote: >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> Hi Weigang, >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> I would like to answer Question 2 first. You can use >>>>>>>>>>>>>>>>>> variables *AOwnerFamily *and *BOwnerFamily *to refer to >>>>>>>>>>>>>>>>>> clump (or owner) A's and clump B's family numbers directly >>>>>>>>>>>>>>>>>> in the force >>>>>>>>>>>>>>>>>> model. So you can write *if *statements that treat each >>>>>>>>>>>>>>>>>> case accordingly. This is mentioned in the DEME paper: You >>>>>>>>>>>>>>>>>> can check out >>>>>>>>>>>>>>>>>> Table 2. >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> For Question 1, the situation is more complicated. We are >>>>>>>>>>>>>>>>>> actually able to reproduce the problem you encountered >>>>>>>>>>>>>>>>>> (simulation >>>>>>>>>>>>>>>>>> freezing), but on consumer/gaming cards only. It runs >>>>>>>>>>>>>>>>>> perfectly on data >>>>>>>>>>>>>>>>>> center cards and that's what we used for generating this >>>>>>>>>>>>>>>>>> experiment, >>>>>>>>>>>>>>>>>> therefore it did not appear a problem for us. It's likely >>>>>>>>>>>>>>>>>> due to different >>>>>>>>>>>>>>>>>> GPU architectures running the same code differently, we'll >>>>>>>>>>>>>>>>>> try to find a >>>>>>>>>>>>>>>>>> solution and let you know in the following days, so stay >>>>>>>>>>>>>>>>>> tuned. By the way, >>>>>>>>>>>>>>>>>> you are using a gaming card to run the simulations, correct? >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> Thank you, >>>>>>>>>>>>>>>>>> Ruochun >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> On Friday, May 24, 2024 at 8:47:00 AM UTC+8 >>>>>>>>>>>>>>>>>> [email protected] wrote: >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> Thank you for your reply! I have two questions about the >>>>>>>>>>>>>>>>>>> demo "DEMdemo-Fracture-Box". >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> (1) After i have run this demo for one day, there is >>>>>>>>>>>>>>>>>>> still nothing outputed. Is it fact that the DEME will run a >>>>>>>>>>>>>>>>>>> long time once >>>>>>>>>>>>>>>>>>> a fracture model is used? >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> (2) How to tell DEME the contact force models between >>>>>>>>>>>>>>>>>>> different familys? I did not see any snippet which >>>>>>>>>>>>>>>>>>> undertakes this work, >>>>>>>>>>>>>>>>>>> although the demo has at least two kinds of contact force >>>>>>>>>>>>>>>>>>> model. The >>>>>>>>>>>>>>>>>>> question i really want to ask is that, if we have more than >>>>>>>>>>>>>>>>>>> three familys >>>>>>>>>>>>>>>>>>> in our model and there are more than two familys consist of >>>>>>>>>>>>>>>>>>> spherical >>>>>>>>>>>>>>>>>>> particles, how to tell DEME the contact force model >>>>>>>>>>>>>>>>>>> between different >>>>>>>>>>>>>>>>>>> familys, and tell DEME the contact force model between the >>>>>>>>>>>>>>>>>>> particles of a >>>>>>>>>>>>>>>>>>> family in the same time. >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> Thank you, >>>>>>>>>>>>>>>>>>> Weigang >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> On Thursday, May 23, 2024 at 10:10:14 PM UTC+8 Ruochun >>>>>>>>>>>>>>>>>>> Zhang wrote: >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>> No. That's because the *sphere components* in a clump >>>>>>>>>>>>>>>>>>>> are just shape representations, and they have no physics, >>>>>>>>>>>>>>>>>>>> only material >>>>>>>>>>>>>>>>>>>> properties. If they did have interaction with each other >>>>>>>>>>>>>>>>>>>> then every clump >>>>>>>>>>>>>>>>>>>> would've immediately exploded upon simulation starting. >>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>> Thank you, >>>>>>>>>>>>>>>>>>>> Ruochun >>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>> On Thursday, May 23, 2024 at 12:16:32 PM UTC+8 >>>>>>>>>>>>>>>>>>>> [email protected] wrote: >>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> Hi Ruochun, >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> Thank you for your reply! I have a question about the >>>>>>>>>>>>>>>>>>>>> clump. Do the particles in a clump interact with each >>>>>>>>>>>>>>>>>>>>> other via any force >>>>>>>>>>>>>>>>>>>>> model? >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> Thank you, >>>>>>>>>>>>>>>>>>>>> Weigang >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> On Monday, May 20, 2024 at 10:26:03 PM UTC+8 Ruochun >>>>>>>>>>>>>>>>>>>>> Zhang wrote: >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>> Hi Weigang, >>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>> Yes. Again, DEME only cares about the position and >>>>>>>>>>>>>>>>>>>>>> radius of the initial spheres, so you can supply it >>>>>>>>>>>>>>>>>>>>>> however you want. If >>>>>>>>>>>>>>>>>>>>>> you have a file that records this information using your >>>>>>>>>>>>>>>>>>>>>> own format, then >>>>>>>>>>>>>>>>>>>>>> the easiest thing is to have your own C++ or Python >>>>>>>>>>>>>>>>>>>>>> script that reads it >>>>>>>>>>>>>>>>>>>>>> into arrays and then feeds them to the solver. If >>>>>>>>>>>>>>>>>>>>>> your file shares the format with DEME's standard clump >>>>>>>>>>>>>>>>>>>>>> output file, or your >>>>>>>>>>>>>>>>>>>>>> file is simply the output of *WriteClumpFile*, then >>>>>>>>>>>>>>>>>>>>>> you can conveniently load clump positions and >>>>>>>>>>>>>>>>>>>>>> orientations by *ReadClumpXyzFromCsv >>>>>>>>>>>>>>>>>>>>>> *and *ReadClumpQuatFromCsv *(examples are in >>>>>>>>>>>>>>>>>>>>>> GRCPrep_Part1 and 2). Note that currently, sphere radius >>>>>>>>>>>>>>>>>>>>>> cannot be read >>>>>>>>>>>>>>>>>>>>>> from standard clump output files since it's part of the >>>>>>>>>>>>>>>>>>>>>> clump template >>>>>>>>>>>>>>>>>>>>>> information thus not in the clump output. >>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>> Thank you, >>>>>>>>>>>>>>>>>>>>>> Ruochun >>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>> On Monday, May 20, 2024 at 12:56:56 PM UTC+8 >>>>>>>>>>>>>>>>>>>>>> [email protected] wrote: >>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>> Hi Everyone, >>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>> I would like to generate a block which consists of a >>>>>>>>>>>>>>>>>>>>>>> assembly spheres. Is it possible to generate the block >>>>>>>>>>>>>>>>>>>>>>> by other code, and >>>>>>>>>>>>>>>>>>>>>>> then load it into DEM-Engine via a file containg the >>>>>>>>>>>>>>>>>>>>>>> informations (such as >>>>>>>>>>>>>>>>>>>>>>> position and radius) of the spheres? >>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>> Thank you, >>>>>>>>>>>>>>>>>>>>>>> Weigang >>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>> -- >>>>>>>>>>>>>>>> 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/1910af21-d1e3-43dd-a779-0c229e6150a6n%40googlegroups.com >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> <https://groups.google.com/d/msgid/projectchrono/1910af21-d1e3-43dd-a779-0c229e6150a6n%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>>>>>>>>>>>>> . >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>> -- You received this message because you are subscribed to the Google Groups "ProjectChrono" group. 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