fix indent plane question

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1

Dear All:

This question does not appear to be asked before in this list

I'm defining a "plane indenter" by following fix

    fix upper all indent 10.0 plane z +98.0 hi units box
    fix lower all indent 10.0 plane z -98.0 lo units box

This should give a uni-axial compression of the material between the "two planes" above

I can print pzz (compressive stress) versus strain. However, I want to get "load versus strain"

Does f_upper and f_lower give load? If yes, what are the units ?

Thanks

Srini

2

the fixx indent documentation says the following:

3

Dear Axel:

Thanks for your reply. I thought I understood this man page writeup. But when I print f_upper and u_lower using following:

thermo_style custom step temp pe etotal press pxx pyy pzz f_upper f_lower

I only get one scalar printer for f_upper and f_lower (when I expected an array to be printed)

Thanks again

Srini

4

dear srini,

Dear Axel:

Thanks for your reply. I thought I understood this man page writeup. But when I print f_upper and u_lower using following:

thermo_style custom step temp pe etotal press pxx pyy pzz f_upper f_lower

I only get one scalar printer for f_upper and f_lower (when I expected an array to be printed)

if you ask for printing a scalar, like you did, then the fix
will return the scalar (i.e. the energy) to thermo, if you ask
for a vector property (f_upper[1] f_upper[2] f_upper[3]) you'll
get the force vector components.

HTH,
   axel.

5

Dear Axel:

Thanks. I completely misunderstood the printing part of the fix. I thought giving the names f_lower and f_upper will print the whole array.

Since I want the Z-load (f_z) I will have to specify f_upper[3] and f_lower[3].

Thanks again

Srini