Although the ignition-and-growth model can simulate the ignition and detonation behavior of traditional energy materials well, it seems insufficient to simulate the impact-induced deflagration behavior of reactive materials (RMs) using current finite element codes due to their more complicated ignition threshold and lower reaction rates. Therefore, a simulation method for the impact-induced deflagration behavior of a reactive materials projectile (RMP) is developed by introducing tunable ignition threshold conditions for RMs, and a user-defined subroutine is formed by the secondary development on the equation of state (EOS). High-velocity impact experiments were performed to prove the validity of simulations. The results show that the user-defined subroutine for RMs is competent in simulating the ignition and deflagration behavior under impact conditions, because the reaction ratio, morphology and temperature distribution of RMP fragments are all well consistent with experiments, theory, and current reports from other researchers. In this way, the quantitative study on the deflagration reaction of RMs can be implemented and relevant mechanisms are revealed more clearly.

To great understanding the dynamic crack propagation of rock under in-situ stress and blasting, the static-dynamic loading experimental platform was built. With different confining pressure (0MPa, 2MPa, 4MPa, 6MPa, 8MPa) and different ratios (K) of horizontal-to-vertical pressure (0, 0.25, 0.5, 0.75, 1), nine texts have been carried out in quadrate granite samples. The dynamic strain gauges and high-speed (HS) camera were used to measure strain field and observe crack growth. According to experimental results, the centrosymmetric damage zone is generated around borehole when K=1, the circumference compressive stress is formed by confining pressure, and it reduces the circumference tensile failure by blast loading. The number and size of the broken radius significantly reduce with confining pressure increases. As K decrease from 1 to 0, the tensile stress concentration is obviously around borehole in the vertical direction, and radial cracks grow from the stress concentration zone and develop into boundary under tensile stress wave from blast loading. From the numerical analysis based on Johnson-Holmquist in AUTODYN, crack branching appear near free boundary obviously, meanwhile the radial cracks grow and run through sample by reflected wave at last. Compared to the experimental results, the evolution and final shape of cracks are agree with the experimental results, the central damage area is less than latter because JWL equation neglect the gas loading in numerical calculation.

Both stress wave superposition and dynamic response process of rock materials are complicated in rock engineering, especially the fracture behavior is difficult to described quantify in the multihole blast loading. The laboratory experiment and a numerical study were performed with granite material to explore stress wave superposition and crack growth in radial and tangential directions. A highspeed photogrammetric system and strain measurement were adopted to obtain the crack propagation and the strain field. The interaction and fragmentation of the stress waves under blasting were simulated. The circumferential tensile stress increased during multihole loading, and the radial cracks further expanded into macroscopic fracture in rock. The development of radial cracks between adjacent holes played a role in rock fracturing. The superposed stress increased nonlinearly with boreholes increased, and both the borehole number and the loading direction influenced the stress field process. The strain field also increased nonlinearly with multihole blasting, and the micro-cracks gradually accumulated. Because of the combined action of the incident and reflected tension waves, the outgoing cracks extended to the boundary along the polygonal path, and the crack branching became seriously around the specimen boundary.