A finite difference program is developed to predict the mass loss, nose shape change, and penetration depth of a steel projectile which penetrates into concrete targets based on the modified empirical equation of nose surface abrasion velocity and the assumption that the density of the projectile is constant. The model predictions are compared with the experimental results available in the literature, and good agreements are found between the present calculations and the experimental observations in terms of nose shape and mass loss.

The three-dimensional nonlinear dynamics of particle impacting breaking rock is simulated with LS-DYNA3D. The energy conversion curves and the process of rock breaking under steel particle are obtained, and the mechanism of rock breaking is also analyzed. The simulation results agree with the experimental observations basically. Therefore, this simulation is feasible and can be used as a good reference for optimizing hydraulic parameter for oil well drilling.

The explosive welding process always accompanies with explosive vibration, shock waves, overpressure, hazardous gases and noises. A method of designing a hemispherical structure with 36 m in diameter, whose entrance and smoke extraction opening are 8 m in height and 8 m in diameter respectively, is proposed to decrease the influence of overpressure during the explosive welding process. In order to evaluate the rationality and efficiency of the special-made hemispherical structure, the overpressure comparative experiments of blasting are carried out in air and in the special-made hemispherical structure with a 1/6 scale factor. The experimental results prove that the hemispherical structure with a 1/6 scale factor reduces the overpressure efficiently, especially for the propagation distance longer than 20 m. Furthermore, the overpressure along the tangent direction (perpendicular to the entrance of the hemispherical structure) is lowered more than that along the radial direction (the entrance of the hemispherical structure) for the same propagation distance. Considering the characteristics of propagation and reflection of shock waves, the possible reasons for the overpressure decreasing of blasting in the hemispherical structure are also discussed.

In order to describe the combustion and interior ballistics processes of variable burning-rate propellant more accurately, the model of two-phase flow interior ballistics of variable burning-rate propellant is established, which consists of one center hole and double layers. In the charge condition of 30 mm cannon, Lax-Wendroff difference scheme with second order accuracy is used to get the numerical solutions of the model. The pressure and velocity profiles calculated are in good accordance with the actual ones. Therefore this numerical model can truly and accurately reflect the real physical process of interior ballistics. The simulation results show that it is very effective to restrain the pressure waves in the bore of variable burning-rate propellant, which is great benefit for fire safety. The analysis of the calculation parameters, such as phase velocity and bore pressure, plays a guiding role in the further research of the interior ballistics process of variable burning-rate propellant.

Liquid crystal optical elements have important applications in laser facility, and the indium tin oxide (ITO) films are generally used in liquid crystal optical elements as transparent conductive electrodes. Laser induced damage of ITO films leads to failure of liquid crystal optical elements. The laser damage model of ITO films which simulates the temperature distribution and thermal stress distribution was established. The laser damage of ITO films was experimented through pump-probe technology, and the power density producing damage at a probability of 50% (i.e., damage threshold) was obtained by 1-on-1 testing, and the square resistance of the film after laser irradiation was also measured. The experimental data basically agree with the simulated results. The results show that 1 064 nm laser damage of ITO film occurs mainly by thermal stress. The damage of ITO film begins from K9 glass substrate after CW laser irradiation, while the damage begins from the surface of ITO film after pulsed laser irradiation. Furthermore, the laser damage thresholds decrease with the increase of thickness of ITO films. The square resistance of ITO films increases with the increase of laser intensity unless the ITO films have been damaged completely. The optimal thickness of ITO film in liquid crystal optical element depends on the factors of laser damage, transparence and square resistance.

In order to analyze the flow field within the microchannel of dynamic high-pressure microfluidization, the geometric model and mesh model are established, and the pressure and velocity distributions of the flow field in interactive chamber are obtained with SIMPLEC solution algorithm and RNG k-ε model using FLUENT software. The simulated results show that the high-speed jet flow impinging increases the acting force field, and the sharp increment of the flow velocity rapidly increases the velocity gradient and shear stress. All these ensure the excellent effect of the high-pressure microfuidization. In addition, because of the opposite change of the static pressure and velocity in the oscillating chamber, the dramatic changes of static pressure greatly enhance the effect of gas cavity and pressure release, which corrode the material of the interactive chamber. It is desirable to appropriately decrease feeding speed, reduce the fluid separation inlet corner angle, and choose a short discharge nozzle on the condition of ensuring the impinging speed when designing the internal microchannel of interactive chamber.

The loading and unloading paths of shock impact on granular metal were analyzed, and the attenuation of planar explosion shock wave in granular metal was investigated using characteristic method. The results showed that the initial peak pressure of the shock wave was determined by the type and property of the metal, porosity and detonation velocity of the explosive. The higher of impact impedance and porosity of metal and higher the detonation velocity were, the higher initial peak pressure was. The attenuation was determined by the length of explosive, impact impedance and porosity of the metal. The higher of impact impedance and porosity of metal and shorter explosive cylinder was, the more quickly the shock wave attenuated.

A series of plate impact experiments were conducted to probe into the free-surface velocity profiles characteristics of ultra-pure aluminum (Purity: 99.999%) by a velocity interferometer system for any reflector (VISAR). Based on the observed differences of pullback signals in amplitude, pulse width, and two “sudden changes”, the wave profile evolution during fracture process of ultra-pure aluminum from incipient spall to complete rupture is discussed in detail. The reasons for these change behaviors are analyzed with the mesoscopic analysis of “soft-recovery” sample. This paper points out that these characteristics are possibly related to the release rate of stress wave energy and the fracture behavior of material grain. These analysis results are helpful to understand the evolution process of ductile metal dynamic damage.

An elastic/viscoplastic pore collapse model of double-layered hollow sphere, in which the effect of the binder in Plastic Bonded Explosives (PBX) was taken into account, was developed as a hot-spot ignition model in shocked explosives. The space and time distributions of the velocity, strain, temperature and chemical reaction rate in shock compression of the explosive hollow sphere were theoretically calculated. A new expression of reaction rate equation was obtained for the hot-spot ignition. The three-term reaction rate model, consisting of the new hot-spot ignition term, the slow burning term at low-pressure from Kim and the high-pressure reaction term from ZHANG Zhen-Yu, was implemented into the two-dimensional, hydrodynamic finite-element code DYNA2D and used to simulate the one-dimensional shock initiation process of PBX-9501 explosive. The numerical results show that the model can successfully explain the influence of strength and content of the binder in PBX on the shock initiation, and that of particle size and porosity as well.

Nanocrystalline copper was fabricated by severe plastic deformation of coarse-grained copper at high strain rate under explosive loading. The average grain size of the samples was tested by X-ray diffraction analysis, and the deformation process was simulated recur to LS-DYNA3D finite element program. The influence of strain on the grain refining were analyzed quantitatively. The results show that it is feasible to fabricate nanocrystalline copper by explosively dynamic plastic deformation of coarse-grained copper and the grain size of the NC copper can be controlled less than 100 nm, the higher strain is beneficial to the grain refining, and the distribution of the grain size is not uniform along the loading direction.