Numerical Modeling of Concrete Using a Partially Associative Plasticity Model

A description and results from validation studies for the Karagozian & Case (K&C) concrete (KCC) model are presented in this paper. This material model is primarily intended for modeling the dynamic responses of RC structural components. It is based on a partially associative plasticity theory and has proven itself capable of replicating most of the key behaviors of concrete, such as those related to hardening, softening, rate effects, confinement, shear dilatancy, and fracture. Three pressure-sensitive, independent strength surfaces are used by the KCC model to capture the variations in hardening and softening behaviors exhibited by concrete. These three strength surfaces are used to compute a failure surface that reflects the influence on the concrete's behavior of the current stress and strain states at a material point. This dynamic form of the failure surface is realized by interpolating between pairs of fixed-strength surfaces on the basis of the value of a damage parameter computed by the KCC model. Partial associativity is introduced in the flow rule so that the magnitude of the computed shear dilation can be calibrated to match test data. Numerical results obtained from both finite-element (FE) and mesh-free formulations are presented to show the excellent performance of the KCC model for concrete responses induced by quasi-static, blast, and impact loadings. (c) 2015 American Society of Civil Engineers.