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欧阳肥肠

新虫 (初入文坛)

应助: 0 (幼儿园)
金币: 14.5
帖子: 27
在线: 17.9小时
虫号: 23250009
注册: 2020-07-23
专业: 结构工程

[求助] 沥青/二氧化硅复合材料界面拉伸的分子动力学模拟

最近在做沥青和二氧化硅的界面拉拔模拟中，遇到了一个问题，就是固定底下部分沥青，拉拔二氧化硅整体。结果当二氧化硅发生二埃左右的位移时，又会被沥青的力给“扯回去”。请问一下这要怎么解决？
这个是全部in文件：
# Initialization
units          real
boundary       p p s
atom_style    full
neighbor       0.3 bin

#Dreiding potential information
bond_style    harmonic
angle_style    harmonic
dihedral_style opls
pair_style       lj/cut/coul/cut 9.5 9.5
pair_modify    mix geometric
improper_style  cvff
special_bonds lj/coul 0.0 0.0 0.5

read_data    Layer.data

#Area division1
region       sio2 block INF INF INF INF 62.0 INF units box
region       base block INF INF INF INF 70 INF units box
group          sio2 region sio2
group          base region base
group          asphalt subtract all sio2

#minimization
min_style    cg
minimize       1e-10 1e-10 5000 5000

#Equilibration Stage1 (Langevin dynamics at 500 K)
velocity       all create 500.0 1231
fix          1 all nve/limit 0.05
fix          2 all langevin 500.0 500.0 10.0 904297
thermo_style custom step temp press
thermo       100
timestep       1
run          100000
unfix          1
unfix          2
write_data    after.data1

#Equilibration Stage2
fix          1 all nvt temp 500.0 500.0 50
fix          2 all momentum 1 linear 1 1 1
reset_timestep  0
thermo_style custom step temp press
thermo       100
timestep       1
run          100000
unfix          1
unfix          2
write_data    after.data2

#Equilibration Stage3
fix          1 all npt temp 500.0 300.0 50 x 1 1 1000 y 1 1 1000
fix          2 all momentum 1 linear 1 1 1
reset_timestep  0
thermo_style custom step temp press
thermo       100
timestep       1
run          100000
unfix          1
unfix          2
write_data    after.data3

#Equilibration Stage4
fix          1 all npt temp 300.0 300.0 50 x 1 1 1000 y 1 1 1000
fix          2 all momentum 1 linear 1 1 1
reset_timestep  0
thermo_style custom step temp press epair ebond eangle edihed pxx pyy pzz lx ly lz
thermo       100
timestep       1
run          100000
unfix          1
unfix          2
write_data    after.data4
write_restart restart.equil

#Area division2
reset_timestep  0
region       lower block INF INF INF INF INF 30 units box
group          lower region lower
group          mobile subtract all sio2 lower

#changebox to larger
change_box    all z delta 0 100 units box

#Compute settings
compute       1 mobile stress/atom NULL
compute       fzz mobile reduce sum c_1[3]
compute       v mobile voronoi/atom only_group
compute       vv mobile reduce sum c_v[1]
variable       sigma equal c_fzz/(c_vv*10)
compute       d sio2 displace/atom
compute       dd sio2 reduce ave c_d[3]
thermo_style custom step c_dd v_sigma
thermo       10

#Pull-off test
velocity       sio2 set 0.0 0.0 1e-4
fix          1 lower setforce 0.0 0.0 0.0
velocity       lower set 0.0 0.0 0.0
fix          2 all nvt temp 300 300 50
dump          1 all atom 100 tension.xyz
run          20000

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