fix deform + displace_box + ...

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1

Hi,
what is the difference between these two..?

fix deform command
displace_box command

Except "fix deform" has more options?

I have a box and I'm gonna compute elastic constant
using stress/strain curve. when I use this commands

fix 2 all deform 1 x scale 5 y volume z volume remap x
or
fix 2 all deform 1 x scale 5 y volume remap x
or
fix 2 all deform 1 x scale 5 remap x

I can't see any necking and failure.
I know it's impossible somehow to stretch a real metal cube to it's 5 times length
but before it the box should reach failure.
It's whereas when I set a velocity to one side of cube I can see necking and failure.

Thanks.

2

The difference is that fix deform acts continuously during
a run, to change the box size/shape. Displace_box is
a command you issue before/after a run, and it changes
the box size/shape instantaneously to a new value.

Steve