SUMMARY

The resistance of structures to impact is vital to the protection of life and property. The development of advanced materials for such structures often requires extensive experimentation. But despite these efforts, a mechanistic understanding of material deformation and performance cannot be gained using current experimental techniques. The proposed research aims to develop a computational framework for understanding the role of pressure-dependency, microstructural heterogeneity, and fracture during penetration of ultra-high-performance concrete for protective structures. Peridynamics, a nonlocal integral reformulation of the governing laws of solid mechanics, is used to model the material, deformation, and fracture. The peridynamic theory has been demonstrated to be well-suited for modeling dynamic fracture in brittle and quasi-brittle materials. Here, a pressure-dependent peridynamic plasticity model is formulated to study the effect of plasticity and fracture on the penetration of homogeneous concrete structures at the engineering scale. The work is then extended to the mesoscale. At this scale, the cementitious matrix, pores, reinforcement, and interface between the reinforcement and matrix are explicitly modeled. Meso-scale simulations are performed to gain both a homogenized constitutive response and insight into projectile interaction with structural heterogeneity. Finally, the homogenized meso-scale response and structural interaction data are incorporated into the constitutive laws at the engineering-scale. The framework can advance the theory and application of peridynamics while providing an understanding of the primary mesostructural deformation mechanisms during the impact and penetration of cementitious composites.