Bridging Dynamic Particle Fracture and High-Strain Rate Comminution of Granular Continua
Abstract
This project aimed to explain how particle ruptures due to grain-scale fracture influence the energy dissipation in particulate solids subjected to rapid loading, as well as to interpret the rate-sensitivity of these materials with principles of crack growth dynamics and granular physics. To bridge length scales, a continuum law linking the rate of comminution to the failure kinetics of single particles was proposed. Direct visualization based on x-ray tomography was used to assess the evolution of the polydispersity of the material, as well as to constrain the modes of grain fracture with both the statistics and morphology of the breakage products. Such grain-scale data were used to formulate a continuum breakage model, as well as to test its performance against evidence of particle comminution. In addition, data reported in the literature regarding the rate-sensitivity of both breakage and deformation in granular packings were used to formulate a breakage kinetics applicable under both low and high strain rate regimes. Finally, the newly formulated constitutive law was implemented into a computational platform to solve boundary value problems via the Finite Element Method, detailing in this way the ability of the new framework to capture highly heterogeneous grain ruptures by means of data about the initial conditions of the packing and the fracture properties of its grains. The results of this project provide new simulation tools to quantify the influence of a range of grain-scale attributes rarely considered in continuum-scale engineering design protocols (e.g., particle size, shape, and polydispersity). As a result, findings and methods deriving from this project can assist the design of granular barriers and shock absorbers with tunable dissipative characteristics, informing at the same time the fabrication of new materials consisting of interacting units with different morphology and mechanical properties.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 22, 2021
- Accession Number
- AD1205758
Entities
People
- Giuseppe Buscarnera
Organizations
- Northwestern University