Evolutionarily Coupled Finite-Element Mesh-Free Formulation for Modeling Concrete Behaviors under Blast and Impact Loadings: Fid-Bau Portal

Evolutionarily Coupled Finite-Element Mesh-Free Formulation for Modeling Concrete Behaviors under Blast and Impact Loadings

Wu, Youcai / Magallanes, Joseph M. / Choi, Hyung-Jin / Crawford, John E.

Abstract

Abstract

An evolutionarily coupled finite-element (FE) and reproducing kernel (RK) formulation is implemented in the Karagozian and Case–finite element/mesh-free (KC-FEMFRE) code for modeling concrete behaviors under blast and impact loadings. Mesh-free methods, such as the RK particle method, have the capacity to overcome regularization requirements and numerical instabilities that encumber finite-element methods in large deformation problems, and they are also more naturally suited for problems involving material perforation and fragmentation. To enhance efficiency, a novel approach is developed by coupling the FE approximation with the RK approximation in a controllable and evolutionary fashion. A unique domain integration, stabilized conforming nodal integration, is applied to both FE and RK domains, and therefore the state variables are stored at nodal points directly, and thus no state variable transition is required when mesh conversion is performed. This has a wide range of utility, not only related to efficiency of RK simulations, but by providing a consistent numerical approach for element-to-particle conversion. Moreover, the Karagozian and Case concrete (KCC) model is implemented into the KC-FEMFRE framework, and the internal damage variable of the KCC model is used to evolve mesh-free particles. Quasi-static, blast, and high-speed impact problems are simulated by the coupled formulation, and realistic responses are obtained.