Dear lammpser,
I was used the lammps to simulate the CBN cutting tool to cut the steel(Fe-C alloy),I uesd the eam/fs to describe the force between the Fe and C and set the CBN cutting tool as a rigid body. while I run the program for a while ,the atoms in steel will explode to everywhere, can you help me to find out the problem?
![`I9NB~_IQVBC2][email protected]…889…@M.jpg|867x565](upload://6Z71zAkeuzvOmkarBwCPsgPeIv4.jpeg)
my code is pasted below:
units metal # 单位为lammps 中的metel类型
boundary m m m # 边界条件
atom_style atomic # 原子模式
#special_bonds fene
region workpiece1 block 0 47.385 0 30 0 5 units box
region workpiece2 block 47.385 47.91 0 30 0 5 units box
region workpiece3 block 47.91 100 0 30 0 5 units box
region workpiece union 3 workpiece1 workpiece2 workpiece3 units box
region grain prism 160 180 30 65 0 5 -15 0 0 units box
#region grain cone y 127 22.5 2.5 34.50067 20 40 units box
region total union 4 workpiece1 workpiece2 workpiece3 grain units box
#建铁素体
create_box 4 total
mass 1 55.84 #Fe原子
mass 2 12.011 # C 原子
mass 3 10.811 #B原子
mass 4 14.007 #N原子
lattice custom 2.86 a1 1.0 0.0 0.0 &
a2 0.0 1.0 0.0 &
a3 0.0 0.0 1.0 &
basis 0.0 0.0 0.0 &
basis 0.5 0.5 0.5 &
basis 0.0 0.0 0.5 &
basis 0.0 0.5 0.5 &
basis 0.0 0.5 0.0 &
basis 0.5 0.0 0.0 &
basis 0.5 0.5 0.0 &
basis 0.5 0.0 0.5
create_atoms 1 region workpiece1 basis 1 1 basis 2 1 basis 3 2 basis 4 2 basis 5 2 basis 6 2 basis
7 2 basis 8 2 units box
#建奥氏体
lattice custom 3.58 a1 1.0 0.0 0.0 &
a2 0.0 1.0 0.0 &
a3 0.0 0.0 1.0 &
basis 0.0 0.0 0.0 &
basis 0.5 0.5 0.5 &
basis 0.0 0.0 0.5 &
basis 0.0 0.5 0.5 &
basis 0.0 0.5 0.0 &
basis 0.5 0.0 0.0 &
basis 0.5 0.5 0.0 &
basis 0.5 0.0 0.5
create_atoms 1 region workpiece2 basis 1 1 basis 2 2 basis 3 2 basis 4 1 basis 5 2 basis 6 2 basis
7 1 basis 8 1 units box
#建马氏体
lattice custom 3.018 a1 0.943 0.0 0.0 &
a2 0.0 0.943 0.0 &
a3 0.0 0.0 1 &
basis 0.0 0.0 0.0 &
basis 0.5 0.5 0.5 &
basis 0.0 0.0 0.5 &
basis 0.0 0.5 0.5 &
basis 0.0 0.5 0.0 &
basis 0.5 0.0 0.0 &
basis 0.5 0.5 0.0 &
basis 0.5 0.0 0.5
create_atoms 1 region workpiece3 basis 1 1 basis 2 1 basis 3 2 basis 4 2 basis 5 2 basis 6 2 basis
7 2 basis 8 2
lattice diamond 3.615 #CBN砂轮
create_atoms 3 region grain basis 1 4 basis 2 4 basis 3 4 basis 4 4 basis 5 3 basis 6 3 basis 7 3
basis 8 3 units box
group grain region grain
pair_style hybrid lj/cut 10.0 eam/fs # lcbop tersoff
pair_coeff * * eam/fs Fe-C.eam.fs Fe C C C #Fe-C
#pair_coeff * * lcbop C.lcbop NULL C NULL NULL #C-C
#pair_coeff 3 4 lj/cut 0.00759200 3.5 9.7625 #Fe-C
#pair_coeff * * tersoff BNC.tersoff B C B N #B-N
#pair_coeff 1 1 lj/cut 0.105 3.85 10 #Fe-Fe
pair_coeff 2 4 lj/cut 0.004068 3.367 #N-C
pair_coeff 2 3 lj/cut 0.003311 3.411 #B-C
#pair_coeff 1 2 lj/cut 0.003660 3.39#B-C和N-C
pair_coeff 1 3 lj/cut 0.00759200 3.5 9.7625 #Fe-B
pair_coeff 1 4 lj/cut 0.00759200 3.5 9.7625 #Fe-N
neighbor 6 bin
neigh_modify every 1 delay 5 check yes
#bond_style harmonic
#bond_coeff 1 80.0 2.0
region 1 block 5 100 5 30 0 5 units box
region 2 block 10 100 10 30 0 5 units box
group 1 region 1
group 2 region 2
group workpiece region workpiece
group boundary subtract workpiece 1
group hengwen subtract 1 2
group newton subtract workpiece boundary hengwen
group workpiece union newton hengwen
min_style sd # 能量最小化模式，sd
minimize 1.0e-15 1.0e-18 20000 20000 # 能量最小化参数，指数越大最小化程度越深
#write_restart restart.txt
compute 3 all pe/atom # 计算每个原子的势能
compute 4 all ke/atom # 计算每个原子的动能
compute 5 all coord/atom 3.0 # 计算每个原子的近邻原子数
compute temperature2 hengwen temp
compute temperature3 newton temp/region 2
compute p all pressure thermo_temp # 计算应力，计算结果记为p
variable pressx equal c_p[1] #定义变量pressx=c_p[1],c_p[1]的意思是p里第一个值
variable pressy equal c_p[2] #定义变量pressy=c_p[2],c_p[2]的意思是p里第二个值
compute m workpiece stress/atom # 计算工件应力，计算结果记为p
compute n workpiece reduce sum c_m[1] c_m[2] c_m[3]
variable px equal -(c_n[1])/(3vol)
variable py equal -(c_n[2])/(3vol)
compute k grain stress/atom # 计算磨粒应力，计算结果记为p
compute g grain reduce sum c_k[1] c_k[2] c_k[3]
variable pgx equal -(c_g[1])/(3vol)
variable pgy equal -(c_g[2])/(3vol)
velocity boundary set 0.0 0.0 0.0
velocity hengwen create 293.0 5812775 temp temperature2 units box
velocity newton create 293.0 5812775 units box
fix 3 all nve
fix 4 boundary setforce 0.0 0.0 0.0
fix 5 hengwen temp/rescale 10 293.0 293.0 10.0 1.0
fix 6 grain setforce 0.0 0.0 0.0
compute force grain group/group newton
fix 7 grain move linear -1.4 0 0.0 units box # tan=0.025Vw/Vs
dump result all custom 100 dump.*.lammpstrj id type mass x y z xs ys zs c_3 c_4 c_5
#dump result workpiece cfg 100 *.cfg id type xs ys zs x y z
thermo 100
thermo_style custom step c_temperature3 c_force[1] c_force[2] c_force[3] etotal press v_pressx
v_pressy v_px v_py v_pgx v_pgy
timestep 0.001 # 步长 0.001fs
run 21429 # 运行 100 步
best regards
Yao
College of Mechanical Engineering, Donghua University
Room 3034, academy building 4, 2999 North Renmin Road, Songjiang District
Shanghai, 201620, China
Tel: 86-159-0160-8286
Email: [email protected]…8…