Concrete is known as a quasi-brittle material and the microplane model has been proven to be a powerful method to describe its constitutive features. For some dynamic cases, however, numerous microplane models used successfully at small strains are not sufficient to predict the nonlinear behaviour of damaged concrete due to large deformations. In this contribution at hand, a combined plasticity-damage microplane model extended to the finite strain framework is formulated and regularised using implicit gradient enhancement to achieve mesh insensitivity and to obtain more stable finite element solutions. A modified smooth three surface Drucker-Prager yield function with caps is introduced within the compression-tension split. Moreover, a viscoplastic consistency formulation is implemented to deliver rate dependency at dynamic cases. In case of penetration into concrete materials, the proposed model is equipped with an element erosion procedure to yield a better approximation of crack patterns. Numerical examples on impact cases are performed to challenge the capability of the newly proposed model to existing experimental data.
Keywords: concrete; finite strain; implicit gradient enhancement; microplane; plastic-damage model; rate dependency.