WheelDPSimplified-Error

[sumaya]

Hello,

I am looking for some suggestions about how to fix my error for the script wheelDPsimplified. I have changed the script based on my research requirement. My terrain bed is made of glass beads of 3 mm radius, which is very small. The beads are a clump of two and purposely, I have overlapped them slightly. Now the volume is very small compare to the values provided in the demo script. My IXX, IYY, IZZ are also very small  and I am not currently scaling them. There was issue with the bin size but I have temporarily fixed it with the following lines. However, I am currently getting unexpected velocity that's crashing the entire system. I have played with the terrain properties, step size and HPC sampler spacing but nothing seems to fix this problem. Can you please suggest what could be possibly happening?

The error message :

DEME_ERROR(
            "System max velocity is %.7g, exceeded max allowance (%.7g).\nIf this velocity is not abnormal and you "
            "want to increase this allowance, use SetErrorOutVelocity before initializing simulation.\nOtherwise, the "
            "simulation may have diverged and relaxing the physics may help, such as decreasing the step size and "
            "modifying material properties.\nIf this happens at the start of simulation, check if there are initial "
            "penetrations, a.k.a. elements initialized inside walls.",

 Parameters Output  : 

Current number of clumps: 4216

Number of total active devices: 1
User-specified X-dimension range: [-0.45, 0.45]
User-specified Y-dimension range: [-0.102, 0.102]
User-specified Z-dimension range: [-0.155, 0.155]
User-specified dimensions should NOT be larger than the following simulation world.
The dimension of the simulation world: 1.9584000110626221, 0.24480000138282776, 0.48960000276565552
Simulation world X range: [-0.54, 1.4184]
Simulation world Y range: [-0.1224, 0.1224]
Simulation world Z range: [-0.186, 0.3036]
The length unit in this simulation is: 3.5623088680269976e-12
The edge length of a voxel: 2.3345947397501732e-07
The initial time step size: 5e-06
The initial edge length of a bin: 0.012287999153137209
The initial number of bins: 128000
The total number of clumps: 4216
The combined number of component spheres: 8432
The total number of analytical objects: 2
The total number of meshes: 1
Grand total number of owners: 4219
The number of material types: 2
History-based Hertzian contact model is in use.
The solver to set to adaptively change the contact margin size. 

The script crashes shortly after.

Terrain Properties and Co-ordinates :  

x            y             z      r
0.0015 0.0012   0    0.003   

0.0045   0.0028 0    0.003

 Glass beads : auto mat_type_terrain = DEMSim.LoadMaterial({{"E", 6.5e10}, {"nu", 0.245}, {"CoR", 0.926}, {"mu", 0.16}, {"Crr", 0.01}});

// Define the terrain particle templates
   // Calculate its mass and MOI
    float terrain_density = 2500;
    float volume1 = 1.99e-07 ;
    float mass1 = terrain_density * volume1;
    float3 MOI1 = make_float3(1.431e-12, 9.058e-13, 1.282e-12) * terrain_density;

HCPSampler sampler(0.025f);
    float sample_halfheight = 0.124;
    float sample_halfwidth_x = 0.42;
    float sample_halfwidth_y = 0.098;
    float offset_z = bottom + sample_halfheight + 0.01f;

[Ruochun Zhang]

Sumaya,

The test scene you are targeting appears to be perfectly doable, but in order for us to help you, you need to present two things:

1. The error message you gave seems to be the corresponding part of the code, rather than what got output to the screen... Please provide the actual error message.

2. Please provide a visual rendering of the simulation scene, before the crash. Even if it crashes right at the beginning of the simulation, you can still visualize the initial configuration. This is important and without visuals, anything we can say is speculative.

Thank you,

Ruochun