Discrete modeling of ultra-high-performance concrete with application to projectile penetration

• We simulate UHPC by the Lattice Discrete Particle Model.
• Micro-splitting failure influences significantly the behavior of UHPC.
• Fiber reinforcement enhances material ductility in tension.
• Fiber reinforcement has minimal effect on compressive behavior.
• Fiber reinforcement increases post-impact residual strength of UHPC slab.

In this paper, the Lattice Discrete Particle Model for fiber reinforced concrete (LDPM-F) is calibrated and validated with reference to a new high-strength, ultra-high-performance concrete (UHPC) named CORTUF and applied to the simulation of projectile penetration. LDPM-F is a three-dimensional model that simulates concrete at the length scale of coarse aggregate pieces (meso-scale) through the adoption of a discrete modeling framework for both fiber reinforcement and embedding matrix heterogeneity. In this study, CORTUF parameter identification is performed using basic laboratory fiber pull-out experiments and experiments relevant to a CORTUF mix without fiber reinforcement. Extensive comparisons of the numerical predictions against experimental data that were not used during the calibration phase (relevant to both plain CORTUF and CORTUF with fiber reinforcement) are used to validate the calibrated model and to provide solid evidence of its predictive capabilities. Simulations are then carried out to investigate the behavior of protective CORTUF panels subjected to projectile penetration, and the numerical results are discussed with reference to available experimental data obtained at the Engineering Research and Development Center (ERDC).