Time-Resolved Analysis of the Dynamic Behavior of Granular Materials.
Abstract
The objective of this research is to obtain response and constitutive characterization for Concrete and mortar at strain rates up to 105/s, to analyze the evolution of load-carrying and energy absorption capacities, and to understand deformation and failure mechanisms under high pressures. The high rate failure mechanisms considered include fragmentation, comminution and granular flow. Our investigation has focused on (1) the dynamic response of the "G"-mix concrete under impact conditions; (2) the effect of composite microstructure and aggregate reinforcement on the material stress-carrying capacity; and (3) the failure wave phenomenon in mortar under uniaxial-strain impact loading. Experiments and numerical simulations have shown that while the quasistatic uniaxial strength for the concrete is approximately 30 MPa, the average compressive stresses carried by the concrete under the conditions of impact experiments involving elastic steel target plates and impact velocities between 290 - 330 /ma is on the order of 1600 MPa. The marked increase in stress is attributed to the effect of higher strain rates which are on the order of 104/s and to the effect of lateral confining stresses. Experiments also showed that the stresses carried by mortar (matrix phase in concrete) under the same conditions are approximately 1200 MPa or 75 % of that for the concrete (approximately 1600 MPa). Due to the composite microstructures and its relatively coarse aggregate size, the deformation and stresses are nonuniform inside the concrete.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1999
- Accession Number
- ADA373452
Entities
People
- Min Zhou
Organizations
- Georgia Tech