# How can I use another lattice command in Peridynamics?

Hello,

I am currently using the Peridynamics module to simulate some crack issues. From the , the PD only identify the simple cubic.

But in my work , I have to set the lattice constant different in x,y,z to simulate the real materials. How can I use another lattice command ? What files should I modify?

Thank you

Wan

you want a SC-like lattice but with different vectors in x, y, z? you should try the

lattice custom

Yes ,I know ,but in Peridynamics now, It is only the sc(simple cubic) lattice command be used. If I want choose another lattice command, I should do some work. But I don’t know how to do it.

ooops sorry for the noise then, i’ll leave this to the guys that know

Yes ,I know ,but in Peridynamics now, It is only the sc(simple cubic)
lattice command be used. If I want choose another lattice command, I should
do some work. But I don't know how to do it.

are you sure that you need that. keep in mind that peridynamics is a
continuum model,
so its lattice is not related to any crystal lattice of a system. i am
not that much an expert
in this, but in my understanding the particle grid in peridynamics it
is more like using a
calculation. so for as long
as the density of grid points is high enough (i.e. there are enough
particles), there should
be no need for using a different lattice.

axel.

Rezwan (CCd) can comment on whether it makes sense
to use Peridynamics with other lattices, or what happens
if you use the lattice command to setup up PD particles
on some other lattice. PD is a mesoscale
model, so it has no direct connection to, for example, an fcc
lattice for Al or Au at the atomic scale.

Steve

Wan,

The lattice points in lammps are the peridynamic nodes. Theoretically, it should be ok to use any lattice configuration. However, in typical sense we use the 3*lattice_spacing to define the peridynamic horizon. So you need to make sure for nonuniform or arbitrary mesh the horizon is defined correctly (e.g. capturing the physical properties properly). as the lattice size may not be a unique value.

Rezwan (CCd) can comment on whether it makes sense
to use Peridynamics with other lattices, or what happens
if you use the lattice command to setup up PD particles
on some other lattice. PD is a mesoscale
model, so it has no direct connection to, for example, an fcc
lattice for Al or Au at the atomic scale.

Steve