Discrete Element Simulation of Brittle Porous Material Failure

Abstract

The study uses Particle Flow Code (PFC) 2D discrete element software to reproduce the dynamic compressive experiment of foam concrete, a typical brittle porous material, and to calibrate micro-parameters of hardened cement mortar, building a discrete element model of foam concrete. Experimental phenomena and inner mechanisms are further analyzed and studied, leading to conclusions in the deformation characterization, failure mode and failure mechanism of foam concrete specimens under different strain rate loading. The research results indicate that under low strain rate loading, the specimen cracks from inside evenly; the processes from failure to compaction is endoenergetic, resulting in stress plateau phenomenon and even deformation during the experiment. Under high strain rate loading, cracks are generated in an explosive manner at the impacted end, and the specimen on the whole is not damaged evenly. Simulation results basically fit the experiment data. The peak stress curve fitting of concrete foam from under quasi-static conditions to high strain rate is studied, which shows obvious strain rate effect that grows exponentially. By calculating models with different densities, it is found that the compressive strength of foam concrete increases along with the growth of density. Thus, PFC can be used in numerical simulation of dynamic mechanical properties of brittle porous materials.