Determination of K&C model parameters for ultra-high toughness cementitious composites

The ultra-high toughness cementitious composite (UHTCC) has ultra-high ductility, excellent energy absorption capacity, and good durability. These characteristics allow it to have a wide variety of applications in several protective structures. The well-known K&C model is used for concrete-like materials to study their behavior under dynamic load, but it cannot accurately describe the dynamic mechanical properties of UHTCC, a tough cement-based material. To obtain the K&C model parameters suitable for UHTCC, the present paper was based on the existing UHTCC uniaxial compression/tension, compression/tension of Split Hopkinson Pressure Bar (SHPB), and triaxial compression test data to calibrate the damage parameters, strain rate effect parameters and strength surface parameters in the K&C model for UHTCC. Then, the improved K&C model parameters were used to simulate the dynamic response of the UHTCC target subject to the contact explosion loads. The simulation results show that the improved K&C model parameters predict the cratering size on the front surface of the UHTCC plate under the explosion load, which is consistent with the test results in the corresponding literature, and the error is kept within 6%. At the same time, compared with other K&C model parameters, the improved K&C model parameters in this paper can more accurately predict the damage distribution and failure form of the UHTCC plate subjected to explosive load. To further verify the accuracy of the improved K&C model parameters in the present paper, the LS-DYNA software was used to predict the penetration depth of the projectile and the crater diameter of the target subject to the projectile impacts UHTCC at a high speed. The penetration depth and crater diameter are in good agreement with the test results in the literature. © 2022, Editorial Office of Journal of Building Structures. All right reserved.