Modeling Damage and Fragmentation in Concrete

Report No. ARL-RP-169
Authors: John D. Clayton
Date/Pages: April 2007; 22 pages
Abstract: A theory combining nonlinear continuum elasticity, inelasticity, thermodynamics, damage mechanics, and fragmentation is formulated. The model is applied to study concrete subjected to high rate loading as occurs during ballistic impact. Two thermodynamically motivated methods are postulated within this theoretical framework for quantitatively characterizing the mass and velocity distributions of the post-impact debris field, one based upon a local energy balance and a second following global entropy maximization. Here the concrete, a composite mixture of mortar and granite aggregate, is regarded as a homogeneous continuum prior to fragmentation. However, the composite nature of the microstructure directly influences model parameters dictating the mean fragment dimension, here specifically related to the coarse aggregate size. Standard continuum elements represent the intact solid and particles describe eroded material in numerical implementation of the model. The impact of a metal sphere on a thin concrete target, and the subsequent motion of the resulting cloud of concrete fragment debris, are simulated. Fragment size, speed, and kinetic energy statistics predicted by the two methods are compared.
Distribution: Approved for public release
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Last Update / Reviewed: April 1, 2007