Quantitative Characterization Method for the Microcontacts and Macrocontacts of Two-Dimensional Granular Materials

This article puts forward a quantified characterization method of micro- and macrocontacts of granular materials. The microcontact is defined as the contact surface with two voids in its two ends. The macrocontact is defined as a sequence that is composed of microcontacts and satisfies the condition of a one-dimensional manifold. The two dual geometrical systems can be extracted from the granular assembly. The edges and paths in the solid-cell system can realize the quantified topological characterization of the micro- and macrocontacts. For cemented granular materials, each crack can be treated as a gaping contact. The contact characterization can be used to visualize the cracks in the simulation results of the discrete-element method (DEM). The shortest-path algorithm can help judge if there is a macrocrack in the numerical specimen and acquire the quantified failure route. The contact force of an arbitrary macrocontact can be calculated by the vector addition of the force on the particle contacts that compose it.