To steve, regrading berkovich indenter!!

Dear Ray,

thanks for the help, i got it!!
and one more question is, as the indenter moves the temp builds up and stops by err msg
as i previosly said, is there any way to over come the above problem such that i can do large depth or constatnt temp simulation.

once again thanks fo the help

Again, please cc lammps-user mail list, thanks.

Stopping with error due to overheating could be due to a lot of reasons: too fast loading stage, improper active/thermostat regions, bad choice of potential, bad timestep, etc. Instead of silencing the error message, I recommend you find out what might be the cause by starting with the simplest setup possible and perhaps a loading rate as slow as 1 m/s.

Good luck,

Dear Ray,

thanks for the help.
now i got new problem, for sperical the input is working,
but for pyramidal indenter, where indenter is region is defined by intersection of 3 planes

region indentr intersect 3 plane1 plane2 plane3 side out move v_mvx v_mvy v_mvz units box

i am getting the error as

ERROR: Region union or intersect cannot be dynamic (region.cpp:349)

could you please tell me to over come this prolem

thanking you

Answer to your question is also in the “region” doc page.


Dear Ray,

as u said, in region doc page it is given as follows…

“If the move or rotate keywords … cannot be used with a union or intersect style region. Instead, the keywords should be used to make the individual sub-regions of the union or intersect region dynamic.”

according to above line i made the sub regions dynamic with -ve z direction movement
is the following lines are correct

variable z equal -1*step
region plane1 plane {p1} {p2} {p3} {nab1} {nab2} {nab3} move v_x v_y v_z units box
region plane2 plane {p1} {p2} {p3} {nbc1} {nbc2} {nbc3} move v_x v_y v_z units box
region plane3 plane {p1} {p2} {p3} {nca1} {nca2} {nca3} move v_x v_y v_z units box
region indentr intersect 3 plane1 plane2 plane3 side out
group indentr region indentr
fix indent all wall/region indentr harmonic {harmonick} {epsilon} ${cutoff}

p1 p2 p3 are the indenter tip coordinates assume 0 0 5, surface to be indented is at 0 0 0 (z cord tip of indenter > cutoff radius of fix/wall/region/harmonic)

The harmonic force must be excerted on the outward direction of the region formed by the region/intersection command so it is given as side out.

na1 na2 na3,nb1 nb2 nb3, nc1 nc2 nc3 are the unit inward normal to the three planes

still i am getting err as
“ERROR on proc 0: Particle on or inside surface of region used in fix wall/region (fix_wall_region.cpp:234)”
could u please help me to find where i am doing the mistake in the above commands usage

thanking you

Hi Naveen,

Setting sub regions dynamic the way you did is correct, but I am pretty sure your “variable z equal –1*step” is not.
If you think about it, you are displacing your region(s) by the value of “-1 (angstrom)*step” over the entire course of your run, say FINAL-STEP; then your “step” runs from 1 to FINAL-STEP, meaning your expected displacement for your indenter regions throughout the entire loading stage changes every step - that just does not sound right.
You will have to figure your errors out by yourself.