how to prevent particles from penetration in compression test?

Dear Lammps users,

I want to simulate a compression test. I have set a group of particles as the load. But it appears penetration between the simple particles and the load particles (Please the the pictures in the attachment). How can i prevent the particles from penetration?

compression.png

penetration.png

Part of my script is as follows,

group aggregate type 1
group asphalt type 2
group base type 3
group load type 4

set group aggregate meso/rho {rhoaggregate} #set density of aggregate set group asphalt meso/rho {rhoasphalt} #set density of asphalt
reset_timestep 0

pair_style hybrid/overlay sph/taitwater/morris lj/cut {sgmL} pair_coeff * * lj/cut {epsL} {sgmL} pair_coeff 1 1 lj/cut {epsS} {sgmS} pair_coeff 2 2 sph/taitwater/morris {rhoasphalt} {c} {mu} ${h}

bond_style harmonic
bond_coeff 1 {kB} {dB}
bond_coeff 2 {kA} {l}

fix 1 load addforce 0.0 {fmax} 0.0 fix 2 load setforce 0.0 NULL 0.0 fix 3 load rigid single fix 4 aggregate meso fix 5 asphalt meso #fix 6 load meso fix 7 base meso/stationary fix 8 all viscous 1 fix 9 all gravity -9.81 vector 0 1 0 fix 10 load rigid single force 1 off on off torque 1 off off off fix 11 aggregate bond/break 1 1 {dBmax}
fix 12 aggregate bond/break 1 2 ${lmax}
fix 13 all enforce2d

Many thanks and kind regards,
Pengbo Li

Dear Lammps users,

I want to simulate a compression test. I have set a group of particles as the load. But it appears penetration between the simple particles and the load particles (Please the the pictures in the attachment). How can i prevent the particles from penetration?

this is a function of the force/load you generate and the force field between the load generating particles and the rest. lennard-jones is a rather soft potential, so you have to either increase sigma or reduce the load.

axel.

[…]