[lammps-users] "FENE bond too long" caused by indent

Dear all

I am intended to make a cavity in a epoxy matrix which is modeled as (FENE chain and LJ pair). When I add the indent to my input file, and the cavity with an initial r=0.1 begin to expend. However, when it come to 120 steps, it show the error as following. My idea is that bond error is caused by the large k= (force/distance^2 units) or small time step (k=1000 and t=0.012 in my simulation). After replacing a smaller k and time step, the error still exists.

Any suggestions on this problem?

Chen Yu

You're getting the error because one or more bonds are stretching
too far, so that the FENE formula fails. You need to figure
out why that is happening (due to your indenter doing something
too fast or unphysically, most likely) and change it.