Hi all,
Now, I hope to exert force increasing gradually on one end of cnt. And the other end of cnt is fixed. The code is:
label forloop
variable i loop 200
variable forcez equal i*0.4994*(-1) fix 3 upper setforce 0.0 0.0 {forcez}
thermo_style custom step etotal pe ke temp
run 10000
next i
jump in.cntzc forloop

The units of the simulation is metal. But the cnt crashed in the first loop. Can you help me to solve the problem. What is wrong in the code. Thank you.