Confused, about changing coefficient of Friction during LIGGGHTS simulation

Submitted by Rachel on Sat, 12/02/2017 - 23:32

Dear all,
I am doing a research on triaxial test in soils. In my simulation, I have two process, i.e. consolidation and shear process. I want to use the coefficient of friction f=1.0 during consolidation while use f=0.5 during shear process. I haven't found any command about changing this coefficient during simulation. Could anyone please give me a clue about how to realize this function?

Also, I want to ask when I restart a LIGGGHTS code using read_restart command, All of the material parameters are still needed to be defined. If I use a different value of the friction coefficient, e.g. in the original code f=1.0 and I change f into 0.5 after restart, does that mean the new f value will be applied in the new code, or it can only use that f value in the original code?

Any suggestions are greatly appreciated!

Regards,
Rachel

Forums:

medvedeg | Wed, 12/06/2017 - 10:48

Hallo Rachel,

you are right, after read_restart the coefficient of friction will be changed in the simulation if you changed them manually in the input script. So this is the way how to proceed. Alternatively, you can try (I did non test this) to unfix corresponding fix property/global coefficientFriction and apply a new fix with a changed value. Usually I have several input scripts that are executed one by one if a simulation consists of several stages, for example:
1) fill the particles and write restart file
2) read restart file, change material properties, do the rest of the simulation with the packing, and write restart file again
So you can automatise your simulation

Alexander Podlozhnyuk

Rachel | Thu, 12/07/2017 - 23:44

Hello Alexander,

This sounds like a very good idea and now I know how to change the material parameters during a simulation. Thanks for your kind help. I will follow your advice and hope to get some good results.

Kind regards,
Rachel

Mehrdada | Mon, 12/11/2017 - 08:49

Hello Rachel,
I want to model triaxial test. Could you please provide me with your input script, geometry and meshes?

Kind Regards,
Mehrdad