回复： shear strain at 0K

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1

Hi,
About the last problem , i use a loop (displace_atoms — minimization ------ quasidynamic) to achieve the static shear load. However, in this way , the stress-strain curve increase linear even after the dislocation strat to move, which indicate the plastic deformation. Maybe the " Pxz " is proper to represent the shear stress in this simulation ? AND how can i obtain the stress-strain curve include the plastic effect?

The following is my input script about the stress:

compute stress all pressure mytemp #
variable p2 equal “-c_stress[4]/10” # Units:Mpa
variable p3 equal “-c_stress[5]/10”
variable p4 equal “-c_stress[6]/10”

fix print mobile ave/time 1 1000 5000 c_mytemp v_strain v_p2 v_p3 v_p4 c_kre c_pre file INFORMATION${i}.txt

2

Hi,
About the last problem , i use a loop (displace_atoms --- minimization
------ quasidynamic) to achieve the static shear load.

This also is a widely used method.

However, in this way , the stress-strain curve increase linear even after
the dislocation strat to move, which indicate the plastic deformation.
Maybe the " Pxz " is proper to represent the shear stress in this
simulation ?

This is a result of your model (i.e. structure, potential, setup), not a
lammps problem.

AND how can i obtain the stress-strain curve include the plastic effect?

Usually a stress-strain curve should include both an elastic region and a
plastic region. If it does not, it has something to do with your model,
not lammps.

Ray