A constitutive model for concrete subjected to extreme dynamic loadings

Abstract

A good physical-based constitutive model should not only properly reproduce the macroscopic dynamic response of concrete, but also capture the meso-damage behavior that actually occurs. This paper presents a constitutive model for concrete subjected to extreme dynamic loadings with the help of the meso-damage mechanics, Duvaut–Lions formulation and elasto-plastic theory. In the present model, a two-step homogenization scheme of concrete is proposed, where compressive damage and tensile damage are treated dividually. The tensile damage is controlled by the nucleation and growth of micro-cracks, while the compressive damage is related to the collapse of micro-voids. Mori-Tanka method is introduced to establish the relationship between the meso-structural parameters and the macro-physical quantities. What is more, a new cap model coupled to the compressive damage is presented to capture the irreversible deformation induced by the micro-void collapse. The present model, containing the erosion algorithm, was successfully implemented into finite element code LS-DYNA through user-defined material model. In order to validate the present model, dynamic tensile tests, quasi-static triaxial compressive tests, planar impact tests and projectile penetration tests were simulated in sequence. The results show that the present model has good consistency between the predicted results and the experimental data, thus verifying its rationality and practicability. Sensitivity analyses of two erosion criteria and mesh dependency were also carried out to understand the influence of these empirical parameters on the compressive damage and tensile damage predicted by the present model.