To accurately predict the dynamic tensile fracture in concrete materials subjected to impact and blast loadings, this study first establishes a modified Monaghan artificial bulk viscosity computation method within the framework of a non-ordinary state-based peridynamics (NOSB-PD) theory to eliminate numerical oscillations. Subsequently, the corrected strain-rate computation method, previously developed, is integrated into the Kong-Fang concrete material model, which was proposed earlier by the research group to calculate accurately the strain-rate effect during sudden changes. Based on the two methods above, numerical simulations of elastic wave propagation in a one-dimensional rod are conducted, and the results demonstrate that the additional inclusion of the modified Monaghan artificial bulk viscosity force vector state into the original force vector state can effectively suppress the non-physical numerical oscillations caused by the deformation gradient approximation. The superiority of the modified Monaghan artificial bulk viscosity is validated through comparative analysis with the original Monaghan artificial bulk viscosity. Furthermore, the influence of the modified Monaghan artificial bulk viscosity parameters is investigated, and recommended values for these parameters are provided. Finally, the aforementioned model is used to numerically simulate the spall test in concrete specimens, where the effects of including or excluding the modified Monaghan artificial bulk viscosity and different strain-rate computation methods on the prediction results of dynamic tensile fracture are compared and analyzed. The numerical simulation results demonstrate that accurately predicting the dynamic tensile fracture in concrete materials requires simultaneous consideration of the modified Monaghan artificial bulk viscosity and corrected strain-rate computation. The established non-ordinary state-based peridynamics model that accounts for both the modified Monaghan artificial bulk viscosity and corrected strain-rate computation demonstrates strong capabilities in predicting crack locations and quantities based on both qualitative and quantitative analysis metrics. This work provides new insights into the numerical simulation of dynamic tensile fracture in concrete materials under impact and blast loadings.

To investigate the shear-enhanced compaction effect and strain-rate effect on the equation of state (EoS) of concrete-like materials subjected to blast and impact loadings, high-fidelity numerical simulations were performed based on two types of EoS behavior tests for cement mortar, including hydrostatic compression tests and flyer-plate impact tests. These simulations employed the Kong-Fang hydro-elasto-plastic model for concrete-like materials and were implemented using the smoothed particle Galerkin (SPG) algorithm in LS-DYNA, enabling accurate reproduction of complex dynamic mechanical behaviors, including the shear-enhanced compaction effect and strain-rate effect. Based on the high-fidelity numerical simulations described above, a quantitative analysis was conducted to investigate the influence of the shear-enhanced compaction effect and strain-rate effect on EoS behavior of concrete-like materials, and the challenges associated with eliminating the shear-enhanced compaction and strain-rate coupling effects in flyer-plate impact tests were systematically identified. The results demonstrate that the Kong-Fang model, when combined with the SPG algorithm, can accurately simulate the complex dynamic mechanical behaviors of concrete-like materials, including shear-enhanced compaction effect and strain-rate effect. To achieve high-precision simulation of dynamic mechanical behaviors of concrete-like materials subjected to blast and impact loadings across high-medium-low pressure ranges, it is essential to establish an EoS with a wide-range pressure based on experimental data from EoS behavior tests. However, shear-enhanced compaction and strain-rate coupling effects should be eliminated when using flyer-plate impact test data to calibrate the EoS parameters. A paradox arises in the establishment of EoS with wide-range pressure for concrete-like materials, and the application of numerical iteration correction methodology may represent an effective approach to resolving this challenge. These findings provide a theoretical foundation for the future development of a numerical iteration correction methodology to eliminate the shear-enhanced compaction effect and strain-rate effect on the EoS of concrete-like materials, thereby facilitating the establishment of a high-precision EoS with a wide range of pressure for concrete-like materials subjected to impact and blast loadings.

Prefabricated concrete bursting layer has a very important application prospect in the field of protective engineering attributed to its technical advantages including high construction efficiency and construction quality. However, compared with the monolithic cast-in-situ concrete bursting layer, the impact resistance of the prefabricated concrete bursting layer may be significantly reduced because of the interfaces between the prefabricated blocks and the cast-in-situ part. Therefore, it is important for engineers to reasonably design the prefabricated concrete bursting layer to make its penetration resistance comparable to the monolithic one. To this end, a kind of prefabricated bursting layer connected by wet joints and rebars was proposed in our previous study. In order to apply the prefabricated bursting layer in protective engineering, a series of numerical models were developed to further study its penetration resistance. Firstly, based on the Kong-Fang model and smoothed particle Galerkin (SPG) method, the numerical models were developed and validated against the experimental data of projectile penetrating monolithic and prefabricated targets. Then, the validated numerical models were further used to investigate the influences of prefabricated block size, wet joint width and anchorage length, spacing and diameter of rebars on the penetration resistance of prefabricated targets. Numerical results indicate that increasing the width of wet joints, reducing the spacing between rebars, and extending the anchorage length of rebars can significantly enhance the penetration resistance of prefabricated targets. After clarifying the influences of these parameters, an engineering design method for a prefabricated concrete bursting layer was proposed. Finally, based on this method, two prefabricated high performance concrete targets subjected to two typical types of warhead penetration were designed. Numerical results show that the penetration resistances of two prefabricated targets were comparable to monolithic targets. The proposed engineering design method can provide a reference for engineering applications of prefabricated concrete bursting layers connected by the wet joints and rebars.