Re: [Yade-users] [Question #683001]: Physic interaction betweem sphere and polyhedra
Question #683001 on Yade changed: https://answers.launchpad.net/yade/+question/683001 Status: Open => Answered Jan Stránský proposed the following answer: > What puzzles me is that polyhedra do not have radius r, then how to calculate normal stiffness between polyhedra and sphere the same way as it does for walls, facets... just considers that the other body has some artificial radius related to the sphere's radius (e.g. equal) [1,2,3] cheers Jan [1] https://gitlab.com/yade-dev/trunk/blob/master/pkg/dem/FrictPhys.cpp#L19 [2] https://gitlab.com/yade-dev/trunk/blob/master/pkg/dem/Polyhedra_Ig2.cpp#L419 [3] https://gitlab.com/yade-dev/trunk/blob/master/pkg/dem/Polyhedra_Ig2.cpp#L335 -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
[Yade-users] [Question #683001]: Physic interaction betweem sphere and polyhedra
New question #683001 on Yade:
https://answers.launchpad.net/yade/+question/683001
hello
i know that Ig2_Sphere_Polyhedra_ScGeom can calculate the ig between
polyhedra and sphere, if the material of polyhedra is polyhedraMat and sphere
is frictMat, the ip between them can be calculate by
Ip2_FrictMat_PolyhedraMat_FrictPhys, and then use cundall law, the interaction
between polyhedra and sphere can be solved.
Ip2_FrictMat_PolyhedraMat_FrictPhys describe in Polyhedra.cpp is as below:
void Ip2_FrictMat_PolyhedraMat_FrictPhys::go(const shared_ptr& pp1,
const shared_ptr& pp2, const shared_ptr& interaction){
const shared_ptr& mat1 = YADE_PTR_CAST(pp1);
const shared_ptr& mat2 = YADE_PTR_CAST(pp2);
Ip2_FrictMat_FrictMat_FrictPhys().go(mat1,mat2,interaction);
}
and stiffness culculate in Ip2_FrictMat_FrictMat_FrictPhys() is like that:
Real Kn = 2*Ea*Ra*Eb*Rb/(Ea*Ra+Eb*Rb);
Real Ks = 2*Ea*Ra*Va*Eb*Rb*Vb/(Ea*Ra*Va+Eb*Rb*Vb);
What puzzles me is that polyhedra do not have radius r, then how to calculate
normal stiffness between polyhedra and sphere use
Ip2_FrictMat_PolyhedraMat_FrictPhys?
lookforward for your answer.
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Re: [Yade-users] [Question #682290]: the correct use of collider.avoidSelfInteractionMask ?
Question #682290 on Yade changed: https://answers.launchpad.net/yade/+question/682290 Luc OGER posted a new comment: I have tried with two very different machines: laptop : hp envy and server Dell R960 BUT I got the same answer??? here the CPUINFO: server Dell : processor : 127 vendor_id : GenuineIntel cpu family : 6 model : 79 model name : Intel(R) Xeon(R) CPU E7-4850 v4 @ 2.10GHz stepping: 1 microcode : 0xb2e cpu MHz : 2094.877 cache size : 40960 KB physical id : 3 siblings: 32 core id : 15 cpu cores : 16 apicid : 127 initial apicid : 127 fpu : yes fpu_exception : yes cpuid level : 20 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb cat_l3 cdp_l3 invpcid_single pti ssbd ibrs ibpb stibp tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm cqm rdt_a rdseed adx smap intel_pt xsaveopt cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local dtherm ida arat pln pts flush_l1d bugs: cpu_meltdown spectre_v1 spectre_v2 spec_store_bypass l1tf bogomips: 4191.91 clflush size: 64 cache_alignment : 64 address sizes : 46 bits physical, 48 bits virtual Laptop HP-ENVY: processor : 7 vendor_id : GenuineIntel cpu family : 6 model : 94 model name : Intel(R) Core(TM) i7-6700HQ CPU @ 2.60GHz stepping: 3 microcode : 0xcc cpu MHz : 2600.000 cache size : 6144 KB physical id : 0 siblings: 8 core id : 3 cpu cores : 4 apicid : 7 initial apicid : 7 fpu : yes fpu_exception : yes cpuid level : 22 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb invpcid_single pti ssbd ibrs ibpb stibp tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm mpx rdseed adx smap clflushopt intel_pt xsaveopt xsavec xgetbv1 xsaves dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp md_clear flush_l1d bugs: cpu_meltdown spectre_v1 spectre_v2 spec_store_bypass l1tf mds bogomips: 5184.00 clflush size: 64 cache_alignment : 64 address sizes : 39 bits physical, 48 bits virtual -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
Re: [Yade-users] [Question #682985]: A strange phenomenon in constant-p(mean stress) simulations
Question #682985 on Yade changed: https://answers.launchpad.net/yade/+question/682985 Description changed to: Hello, everyone! I'm trying to take a constant-p simulation under different b(intermediate principal stress ratio) with Yade but the result seems to be a bit strange. I used non-spherical clumped particle consisting of two identical spheres and periodic boundary condition. In the Stress ratio-Deviation strain curve with different b(sorry I don't know how to upload the picture), When b=0.0 and 1.0, the curve is quite normal whose stress ratio has a peak and then drops, becomes steady. But when b=0.25 and 0.25, after the peak, the stress ratio drops and then rises. The residual value of it is even higher than the stress ratio when deviation strain is 0.3. In my mind, this phenomenon would not happen in reality. Actually, some researchers also do constant-p simulation with PFC-3D or Liggghts, but their results didn't show this phenomenon. Looking forward to your help, Thanks! This is parts of my code: O.engines=[ ForceResetter(), InsertionSortCollider([Bo1_Sphere_Aabb()]), InteractionLoop( [Ig2_Sphere_Sphere_ScGeom()], [Ip2_FrictMat_FrictMat_FrictPhys()], [Law2_ScGeom_FrictPhys_CundallStrack()] ), PeriTriaxController(label='triax', # specify target values and whether they are strains or stresses goal=(sigmaIso1,sigmaIso1,sigmaIso1),stressMask=7, # type of servo-control dynCell=True,maxStrainRate=(10,10,10), # wait until the unbalanced force goes below this value maxUnbalanced=0.01,relStressTol=1e-3, # call this function when goal is reached and the packing is stable doneHook='compactionFinished1()' ), NewtonIntegrator(damping=.2), PyRunner(command='check()',iterPeriod=100), ] O.dt=.5*PWaveTimeStep() def compactionFinished(): O.cell.trsf=Matrix3.Identity triax.goal=(sigmaIso,sigmaIso,-.8) triax.stressMask=3 triax.maxStrainRate=(1.,1.,.01) triax.doneHook='triaxFinished()' O.engines = O.engines + [PyRunner(command='history()',iterPeriod=200,label='recorder')] O.engines = O.engines + [PyRunner(command='changeGoalStress()',iterPeriod=50,label='checker')] triax.maxUnbalanced=10 def changeGoalStress(): s11=-triax.stress[0] s22=-triax.stress[1] s33=-triax.stress[2] r=-((b + 1.0) * s33 -1 * 3 * 10) / (b - 2.0) s=-((1.0 - 2 * b ) * s33 + (b - 1) * 3 * 10) / (b - 2.0) triax.goal=(r,s,-0.8) -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
[Yade-users] [Question #682985]: A strange phenomenon in constant-p(mean stress) simulations
New question #682985 on Yade: https://answers.launchpad.net/yade/+question/682985 Hello, everyone! I'm trying to take a constant-p simulation under different b(intermediate principal stress ratio) with Yade but the result seems to be a bit strange. I used non-spherical clumped particle consisting of two identical spheres and periodic boundary condition. And this is the Stress ratio-Deviation strain curve with different b. As you can see, when b=0.0 and 1.0, the curve is quite normal whose stress ratio has a peak and then drops, becomes steady. But when b=0.25 and 0.25, after the peak, the stress ratio drops and then rises. The residual value of it is even higher than the stress ratio when deviation strain is 0.3. In my mind, this phenomenon would not happen in reality. Actually, some researchers also do constant-p simulation with PFC-3D or Liggghts, but their results didn't show this phenomenon. Looking forward to your help, Thanks! This is parts of my code: O.engines=[ ForceResetter(), InsertionSortCollider([Bo1_Sphere_Aabb()]), InteractionLoop( [Ig2_Sphere_Sphere_ScGeom()], [Ip2_FrictMat_FrictMat_FrictPhys()], [Law2_ScGeom_FrictPhys_CundallStrack()] ), PeriTriaxController(label='triax', # specify target values and whether they are strains or stresses goal=(sigmaIso1,sigmaIso1,sigmaIso1),stressMask=7, # type of servo-control dynCell=True,maxStrainRate=(10,10,10), # wait until the unbalanced force goes below this value maxUnbalanced=0.01,relStressTol=1e-3, # call this function when goal is reached and the packing is stable doneHook='compactionFinished1()' ), NewtonIntegrator(damping=.2), PyRunner(command='check()',iterPeriod=100), ] O.dt=.5*PWaveTimeStep() def compactionFinished(): O.cell.trsf=Matrix3.Identity triax.goal=(sigmaIso,sigmaIso,-.8) triax.stressMask=3 triax.maxStrainRate=(1.,1.,.01) triax.doneHook='triaxFinished()' O.engines = O.engines + [PyRunner(command='history()',iterPeriod=200,label='recorder')] O.engines = O.engines + [PyRunner(command='changeGoalStress()',iterPeriod=50,label='checker')] triax.maxUnbalanced=10 def changeGoalStress(): s11=-triax.stress[0] s22=-triax.stress[1] s33=-triax.stress[2] r=-((b + 1.0) * s33 -1 * 3 * 10) / (b - 2.0) s=-((1.0 - 2 * b ) * s33 + (b - 1) * 3 * 10) / (b - 2.0) triax.goal=(r,s,-0.8) -- You received this question notification because your team yade-users is an answer contact for Yade. ___ Mailing list: https://launchpad.net/~yade-users Post to : yade-users@lists.launchpad.net Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
