Pre-design estimation of reinforced concrete structures’ nonlinear behavior under the action of intensive loads

Modeling the nonlinear response of concrete and reinforced concrete (RC) structures to the effects of high-intensity loads leading to the material's compaction, fragmentation, and cracking is a complex mathematical problem. Its solution is required when designing nonstandard civil structures and facilities at the design stage without access to experimental data. The work develops a methodology for calculating such structures' global and local strengths for applied use with the LS-DYNA solver. We consider the accuracy and reliability of the results obtained and aspects related to their direct application. This work studies the theoretical aspects of the Continuous Surface Cap Model (CSCM) material model. A refined procedure for calibrating the parameters based on the axial compressive strength has been developed. The model's performance was thus verified by comparison with analytical relationships and the results of physical experiments. The range of loading velocities of the structure, from quasi-static to high-speed (including the impact of an air shock wave and penetration by a rigid body at velocities of about 700 m/s), is considered. In addition to the possibility of modeling nonlinear failure mechanics, such applied issues as effective coupling of reinforcing rods with the concrete volume, techniques of modeling of concrete fragmentation and erosion for perforation simulation, the performance of material model with smoothed particle hydrodynamics method (SPH), the selection of the optimal size of finite element (FE) mesh for solving problems of local and global strength, the use of tied contacts to simplify the process of creating models of large building structures are considered. The critical results of this methodology are available in open-access publications in scientific journals and conference proceedings, allowing for reuse when writing scientific reports and project documentation and reducing the time it takes to develop them.