			# 2d LJ crack simulation

			dimension 2
			boundary s s p

			atom_style atomic
			neighbor 0.3 bin
			neigh_modify delay 5

			# create geometry

			lattice hex 0.93
			region box block 0 100 0 40 -0.25 0.25
			create_box 5 box
			create_atoms 1 box

			mass 1 1.0
			mass 2 1.0
			mass 3 1.0
			mass 4 1.0
			mass 5 1.0

			# LJ potentials

			pair_style lj/cut 2.5
			pair_coeff * * 1.0 1.0 2.5

			# define groups

			region 1 block INF INF INF 1.25 INF INF
			group lower region 1
			region 2 block INF INF 38.75 INF INF INF
			group upper region 2
			group boundary union lower upper
			group mobile subtract all boundary

			region leftupper block INF 20 20 INF INF INF
			region leftlower block INF 20 INF 20 INF INF
			group leftupper region leftupper
			group leftlower region leftlower

			set group leftupper type 2
			set group leftlower type 3
			set group lower type 4
			set group upper type 5

			# initial velocities

			compute new mobile temp
			velocity mobile create 0.01 887723 temp new
			velocity upper set 0.0 0.3 0.0
			velocity mobile ramp vy 0.0 0.3 y 1.25 38.75 sum yes

			# fixes

			fix 1 all nve
			fix 2 boundary setforce NULL 0.0 0.0

			# run

			timestep 0.003
			thermo 200
			thermo_modify temp new

			neigh_modify exclude type 2 3
			dump 1 all atom 500 dump.crack
			run 5000

lammps/examples/crack/in.crack
8a8c46a372b0lammm-master

in.crack
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