Ultra-high performance concrete subjected to high-velocity projectile impact: implementation of K&C model with consideration of failure surfaces and dynamic increase factors

Abstract

The K&C material model is widely used to numerically predict the responses of concrete structures against impact or blast loadings. In the literature, most of the K&C parameters are calibrated for normal strength concretes (NSCs), and are thus not directly applicable for ultra-high performance concretes (UHPCs). Moreover, many existing work on UHPCs involve ad-hoc calibrations of the K&C parameters, which may not be applicable for situations beyond the calibration conditions. In this study focusing on UHPCs, a systematic calibration of the K&C failure surfaces and dynamic increase factors (DIFs) is carried out based on available experimental data in the literature. General guidelines on the determination of other model parameters are also provided. Following this systematic determination of material parameters, the predictive capability of the K&C model is demonstrated by considering several sets of experimental data on high-velocity projectile impact (HVPI) against UHPCs, across a wide range of UHPC material properties and mix designs, specimen and / or projectile geometrical details, and loading conditions. Good numerical predictions in terms of penetration depth and crater size are obtained, which suggests that the proposed implementation procedure can be adopted with reasonable confidence, especially during preliminary studies where the relevant experimental data are limited / not available.