Potential File issue

LAMMPS LAMMPS Beginners
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1

Hello,
I am trying to simulate a Copper-Coated SWCNTs in Al Metal Matrix Composites to find its mechanical characteristics. Before Minimization and Thermal Equilibration, I have frozen cnt and coating. When I am running my code, the matrix is getting distorted.
Before:

100
1001642Ă—802 112 KB

After:
200
2001650Ă—811 144 KB

Is there any problem with defining Interatomic Potential ?
What should I do now?

Code:

units      	        metal
variable   	    T equal 300
variable    	dt equal 0.01
dimension   	3
boundary    	p p p
atom_style   	atomic

read_data       model.lmp 

#### Assign atom types 
mass 1 26.98   # Al
mass 2 12.01   # C
mass 3 63.546  # Cu

#### Define interatomic potentials using hybrid
pair_style hybrid airebo 10.2 eam/alloy lj/cut 4.5
pair_coeff * * airebo CH.airebo NULL C NULL 
pair_coeff 1 2  lj/cut 0.03438 3.01
pair_coeff 3 2  lj/cut 0.02578 3.0825
pair_coeff * * eam/alloy al-cu-set.eam.alloy Al NULL Cu

#### Define groups
group CNT type 2
group coating type 3 
group CNT_coating union CNT coating
group matrix subtract all CNT_coating

#### Freeze CNT and coating atoms during minimization
fix freezeCNT_coating CNT_coating setforce 0.0 0.0 0.0

#### Define simulation parameters
neighbor 2 bin
neigh_modify delay 0 every 1 check yes 

#### energy minimization
min_style cg
minimize 1.0e-6 1 10000 10000  # Energy tolerance = 1.0e-6, Force tolerance = 1.0eV/Ă…


#### Thermal Equilibration under NPT (40 ps)
velocity matrix create 300.0 5812775 mom yes rot yes dist gaussian    # Initialize at 300 K
fix 1 matrix npt temp 300.0 300.0 $(100.0*dt)  iso 0.0  0.0 $(1000.0*dt)    # NPT ensemble, 0 bar pressure
fix 5 matrix temp/rescale 10 300 300 1 0.5 
timestep 0.0001  # Time step of 1 fs
thermo 100
dump 1 all custom 100 dump_n1.lammpstrj id type x y z
run 10000  

unfix freezeCNT_coating
unfix 1

#### Uniaxial Tensile Deformation in z-direction (NVT Ensemble)
timestep 0.01
fix 2 matrix nvt temp 300.0 300.0 $(100.0*dt)  # NVT ensemble at 300 K
fix 3 all deform 1 z erate 1.0e-4 remap x

#### Output strain and stress info to file
#### For units metal, pressure is in [bars] = 100 [kPa] = 1/10000 [GPa]
#### p2, p3, p4 are in GPa 

variable tmp equal "lx"
variable L0 equal {tmp}
print "Initial Length, L0: ${L0}"
variable strain equal "(lz - v_L0)/v_L0"
variable p1 equal "v_strain"
variable p2 equal "-pxx/10000"
variable p3 equal "-pyy/10000"
variable p4 equal "-pzz/10000"
fix def1 all print 100 "{p1} {p2} {p3} {p4}" file alloy.def1.txt screen no

dump 2 all atom 50 dump.final
thermo 	100
thermo_style   custom step v_strain temp v_p2 v_p3 v_p4 ke pe press

run 200000 ```
2

Before people can give advice, they have to be able to properly read your input file. Can you?
Also, it doesn’t seem to be complete.

Please see the forum guidelines for how to properly format quoted text, what information to provide, and generally what kind of answer you can get and how you pose questions properly.

What makes you think that?

Have you carefully checked your output/log for warnings?

3

Extremely sorry sir for this inconvenience.

Sir, the code is running without any issues, which is why I’m unable to identify where the problem lies.

4

That an input is running to completion is by no means an indication that it is producing meaningful results and that it has no warnings that should worry you. From looking at the pieces of input that are readable, I am certain that there is at least one serious warning.

6

You are not paying attention. I am not talking about errors but about warnings.

When I talk about a “serious warning”, then I am referring to a warning that must not be ignored.

1 Like
7

Yes, sir.
In log file, there is no warning.
I found an error that is “ERROR on proc 0: All pair coeffs are not set (src/pair_hybrid.cpp:718)”.
Sir, I have read the documentation and as per documentation, I have explicitly used potential for each pair (AIREBO for C-C , LJ for Al-C and Cu-C, EAM for Al-Al, Al-Cu, and Cu-Cu).
I am unable to understand the cause of this error.

8

You keep contradicting yourself, ignoring my comments, and still have neither produced a readable input deck nor the additional information described in the forum guidelines.

I am at the end of my patience and will ignore future posts.

9

Sir, I sincerely apologize for any confusion or frustration caused by my recent communications. I acknowledge that I have not provided the necessary details or followed the guidelines as expected. It was not my intention to overlook your feedback and I greatly appreciate the time and effort you have taken to address my concerns.
Moving forward, I will ensure that I thoroughly review and adhere to the guidelines. I value your insights and hope to have the opportunity to correct my mistakes.