DEM simulation of mechanical behavior in one-dimensional compression of crushable ceramic pebble bed

Abstract The mechanical behavior in one-dimensional compression of a crushable ceramic pebble bed for the fusion reactor, which is under different crushing ratio assumptions (0% - 2%), was numerically investigated by the discrete element method (DEM) simulation. The crushed particle was modeled by a reduction of the particle radius, therefore, the instantaneous decrease of the local stress could be produced. To guarantee the mass conservation of the particles in the pebble bed, the sub-particle insertion process was conducted. Please note that this paper mainly deals with the post of failure of the particles, hence the pebble failure process was not captured. The results showed that the crushed particles could make the pebble bed softer, and with the same Li4SiO4 pebble bed strain, the bed stress decreased as the crushing ratio grew larger. The impact of the crushing ratio on the radial and axial local packing factor was limited on the oscillating amplitude without affecting the oscillating width. Besides, the effects of the coefficient of friction and restitution under different crushing ratios were investigated. At last, the analysis of changes in the average coordination number with the bed strain under different crushing ratios was performed.