LIGGGHTS® - User Forum

Hi,

i m trying to run my first simple simulation but an error comes

ERROR: Mesh error: dimensions too small - use different unit system (../multi_node_mesh_parallel_I.h:584)

I actually used SI unit and stl. file in ASCII file.

I can post some codes of mein and look forward to get some advices:

#Definition of boundaries
variable xmin equal -0.0102
variable xmax equal 0.0102

variable ymin equal -0.042
variable ymax equal 0.042

variable zmin equal -0.042
variable zmax equal 0.042

Hi
I want to fill the bonded particles in a region, as shown in attached figure. I am using lattice command for the same, however I am getting thr following error:
ERROR on proc 0: Neighbor list overflow, boost neigh_modify one (../neigh_gran.cpp:188)

I belive, it is related to the line# 135& 136 of the attached input script.
I am using 'nsq' instead of 'bin' since I was unable to insert the particles using bin.

Please suggest a way aroung the above problem.

Thanks
Shubham

Hi
I have two questions:
(i)
I am trying to model a problem as attached in the figure. A soft web is bonded to a rigid substrate which is moving at constant speed. Whwn web hits the wall, it should delaminate. However as shown, in my case particles are penetrating the wall. I have tried increasing the contact stiffness, but its not helping.
Can someone please help me with this, I have also attache the input file.

Hello
I am using "Flexible fiber" version and have a general question. In the 'lib' folder I found several ANCF beam libraries. I am wondering whether they can be used in Discrete method, or FE by importing a CAD file.

Thanks
Shubham

Hi
I am trying to break granular tupe bonds, by using the command:
fix bondbr3 all bond/break 1 2 ${adh_crit_dist}
2- bondtype
${adh_crit_dist} - critical distang to break the bond

I have also tried fix bondbr3 all bond/break/gran 1 2 ${adh_crit_dist}
But I am getting the following error:
Invalid fix style: "bond/break"

Can we model bond breakage for granular bonds?

Thanks

Hi
I wan to simulate a system very close to as shown in attached figure.
A discrete plastic web is bonded to a non-deformable but movable substrate. As the web his the wall, web should de-laminate from the substrate depending on the bond strengths.
How can the above problem modeled in LIGGGHTS?
How can we create breakable bonds between particle and non-deformable substrate?

Requesting for help, I am struggling a lot, as I am new to the environment

Thanks

Hello
I am trying to simulate a fiber fall. Once they hit the ground, i want to cross-link the fibers based on a critical distance. For cross link bond formation, i am using bond/create command. How wever I an getting the folloing error:
ERROR: Invalid fix style: "bond/create" (../modify.cpp:852)

Thanks
SHUBHAM

Following is my input script:
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
atom_style sphere
atom_modify map array sort 0 0
boundary m m m
newton off

communicate single vel yes

I am trying to set up a basic homogeneous cooling simulation. I am loading in 1000 particles in a periodic domain. Initially, I run the simulation with coefficient of restitution equal to 1. To me, this should result in a nearly constant kinetic energy for the system. However, the velocities shoot way up (depending on time step size). Eventually the kinetic energy decreases as expected after a lower coefficient of restitution is set. My question is what is causing the kinetic energy to increase? This should not even be physically possible if there is no gravitational force.

Hi, I am trying to run a triaxial test. I have defined properties as:
# interaction property [NOTE: Young's modulus value is same for both particle and wall]
variable y1 equal 65e9 # Young's Modulus particle-particle [Pa]
variable y2 equal 6.5e9 # Young's Modulus particle-wall [Pa]
variable us_pp equal 0.15 # Coefficient of static friction particle-particle
variable us_pw equal 0.05 # Coefficient of static friction particle-wall
variable ur_pp equal 0.01 # Coefficient of rolling friction particle-particle