Discrete simulation of model, loose cohesive powders: plastic consolidation, fractal microstructure and tensile strength

Abstract

Abstract. Isotropic packings of cohesive disks in 2D are studied by discrete, stress-controlled numerical simulations. Depending on the assembling process and on whether contacts possess rolling resistance (RR), configurations form under low pressure P with varying solid fraction Φ and fractal dimension d F describing small scale correlations below some blob size ξ . The gradual collapse observed under growing P is described as a linear relation between ln P and 1/Φ within some range, once the influence of initial conditions has faded out, and until a maximum density is approached. This corresponds to a decrease of ξ that is compatible with the fractal blob model. The isotropic tensile strength is always considerably smaller than the naive Rumpf estimate, and grows with consolidation. Coordination numbers in systems with small RR change little while density increases by large amounts in consolidation.

Computer simulation of model cohesive powders: Influence of assembling procedure and contact laws on low consolidation states

“…III) low density, tenuous structures are then stabilized by adhesion, and the relevant force scale is F 0 . However, as briefly reported in [53], such structures tend to collapse upon increasing P * . These phenomena will be the subject of another paper [42].…”