ERROR: Length not sufficient for variable youngsModulus

JF's picture
Submitted by JF on Fri, 11/05/2010 - 12:45

Hi all,

I have this small error when I run my simulation :

85589 atoms
82223 atoms in group A
3366 atoms in group B
ERROR: Length not sufficient for variable youngsModulus

Do you know thir error ? How can I resolve this error ?

For information, if there is only one group of atoms (i.e., 85589 atoms in group A), the simulation runs.

Regards
JF

Ps: the Youg's modulus is defined for all groups (i.e., fix m1 all property/global youngsModulus peratomtype 1.e5)

Forums:

Yansan | Fri, 11/05/2010 - 13:57

Hi JF,
You are using 2 atom-types. Therefore you have to define 2 Young-Modulus's. Your command should look something like this:

fix m1 all property/global youngsModulus peratomtype 1.e5 1.e5

With this command both atom-types have a Young-Modulus of 1.e5.

Regards
Yansan

ckloss's picture

ckloss | Fri, 11/05/2010 - 14:39

Yansan is right, you have to define it this way... see doc for pair gran
Just one more note: There will be a fix for multi-material simulations in 1.1.10 to be released on Monday probably, so you may want to wait for that for further simulations.

Cheers,

Christoph

JF's picture

JF | Fri, 11/05/2010 - 15:29

Thank you both !!!! I found my mistake, I was not enough concentrated.

Regards
Jf

fix m1 all property/global youngsModulus peratomtype 1.e5 1.e5
fix m2 all property/global poissonsRatio peratomtype 0.3 0.3
fix m3 all property/global coefficientRestitution peratomtypepair 2 0.7 0.7 0.7 0.7
fix m4 all property/global coefficientFriction peratomtypepair 2 0.2 0.2 0.2 0.2
fix m5 all property/global characteristicVelocity scalar 2.
fix m6 all property/global cohesionEnergyDensity peratomtypepair 2 500 500 500 500

JF's picture

JF | Fri, 11/05/2010 - 15:15

Hi Yansan,

Thank you for this clue, it helped me. I have also other parameters to fix, therefore I followed the indications at the end of pair_gran.html

But I have this error ERROR: Length not sufficient for variable coefficientRestitution
Please, can you help me again ?

Regards
Jf

fix m1 all property/global youngsModulus peratomtype 1.e5 1.e5
fix m2 all property/global poissonsRatio peratomtype 0.3 0.3
fix m3 all property/global coefficientRestitution peratomtypepair 2 0.7 0.7
fix m4 all property/global coefficientFriction peratomtypepair 2 0.2 0.2
fix m5 all property/global characteristicVelocity scalar 2.
fix m6 all property/global cohesionEnergyDensity peratomtypepair 500

#New pair style
pair_style gran/hertz/history 1 1 #Hertzian with cohesion
pair_coeff * *

cgrohs | Fri, 11/05/2010 - 15:22

For coefficient Restitution you need four values when you have two atom types. The same for coefficientFriction and cohesionEnergyDensity.

Regards,
cg

prasantud | Tue, 08/09/2011 - 14:54

Hi Yansan,
could you please help me in overcoming the error coming after the following output.

1764 atoms in group lower
6120 atoms in group upper
7884 atoms in group boundary
4452 atoms in group mobile
ERROR: Trying to access matrix in fix property/global, but row index out of bounds

I have defined the properties as follows
fix m1 all property/global youngsModulus peratomtype 5.e6 5.e6 5.e6 5.e6
fix m2 all property/global poissonsRatio peratomtype 0.45 0.45 0.45 0.45
fix m3 all property/global coefficientRestitution peratomtypepair 4 0.3 0.3 0.3 0.3
fix m4 all property/global coefficientFriction peratomtypepair 4 0.5 0.5 0.5 0.5

thanking you,
Samantaray

ckloss_ | Tue, 08/09/2011 - 15:41

>>fix m3 all property/global coefficientRestitution peratomtypepair 4 0.3 0.3 0.3 0.3
This line is causing you troubles. The 4 means that you should define a 4x4 matrix, like

fix m3 all property/global coefficientRestitution peratomtypepair 4 &
0.3 0.3 0.3 0.3 &
0.3 0.3 0.3 0.3 &
0.3 0.3 0.3 0.3 &
0.3 0.3 0.3 0.3

because coeff of restitution is something you have to define for each pair of atom types

Cheers,
Christoph