Numerical simulations are conducted on the perforation of aluminum targets struck by an ogive-nosed steel projectile using the commercial FEM code ABUQUS/Explicit. It is assumed that the target response can be represented by a velocity dependent forcing function which is derived from spherical cavity expansion (SCE) analysis. Free surface effects are also considered and a modified forcing function is used in numerical simulations. This approximation eliminates the need for discretizing the target as well as the need for a contact algorithm. It is shown that the numerical simulations are in good agreement with the experimental data for 6061-T651 aluminum alloy targets struck by a VAR 4340 steel projectile.

Standard cylinder test technique and data processing method were studied, and new effective techniques of lighting, negative interpretation and data processing for slit scan experiments were established, and the results of displacement, velocity, acceleration and specific kinetic energy of the cylinder wall particle with high precision and abundant information were obtained. VISAR was used to measure the cylinder expansion velocity and displacement simultaneously. The obtained results are consistent with those from slit scan experiments. The testing reliability was further improved.

Deformation experiments have been conducted to investigate the brittle-plastic transition of quartzite under temperature of 500~1 000 ℃ and confining pressure of 1 251~1 440 MPa. Mechanical behavior and microstructural characteristics indicated that the brittle-plastic transition of quartzite in experimental condition underwent three deformation mechanisms, namely the semibrittle faulting, semibrittle flow and plastic flow. At least two transitions of deformation mechanism were involved with increasing temperature. The first is the transition from semibrittle faulting to semibrittle flow at 700~800 ℃, and the second is the transition from semibrittle flow to plastic flow at 900~950 ℃. In comparison with the similar results reported by Hirth and Tullis (1994), the temperatures of two transitions we determined is higher by 100 ℃ than Hirth and Tullis’ results. In addition, coesite was found in the thin section of severely deformed plastic flow samples.

The SrAl₂O₄:Eu²⁺, Dy³⁺ (SED) nanometer phosphors were synthesized at lower temperature by detonation and combustion method, respectively. The effects of synthesis conditions, annealing temperature on the growth behavior, the particle morphologies and optical properties of the as-prepared SED particles were contrasted. It was showed that the mean size of the SED particles prepared by detonation method increased gradually with increasing heat treatment, and that the mean size of the SED particles prepared by combustion method decreased firstly and then increased quickly and had a minimal value at 600 ℃. The mean size of the SED particles prepared by detonation method increased more quickly than that of the SED particles prepared by combustion method at same annealing temperature. Finally, the mechanism for the long afterglow was discussed and some suggestions on how to improve the synthesis methods were also presented.

On the basis of plane shock wave hypothesis, the characteristics of local cavitation and bulk cavitation formation subjected to underwater explosion were theoretically and experimentally studied. The effects of structure dimensions and shock wave parameters on the cavitation formation were analyzed theoretically. Aiming at validating the local cavitation theory, an underwater explosion experiment in a 5-m diameter columned water tank was carried out. The explosion layout was as follows: 50-g TNT charge was placed at a 1-m stand-off away from a 1-m square and 2-mm thick steel plate. Results show that different structure dimensions can affect significantly the formation of local cavitation under the same shock wave parameters, and the quantity and depth of charges play an important role in the bulk cavitation formation. The experimental results basically agree with those of theoretical analysis.

In conventional Split Hopkinson Pressure Bars (SHPB) experiments, the tension pulse reflected from the sample back into the incident bar will travel to the free end of the bar and then will reflect back to the sample as compression wave. As a result, the sample is loaded many times. The single-pulse loading technique of the Hopkinson pressure bars can solve the problem. This paper presents the basic principle of the single-pulse loading technique of Hopkinson pressure bars. The way to calculate the pre-fixed gap between the transfer flange and reaction mass is given. The experimental results with various pre-fixed gap are obtained. A device of the single-pulse loading technique is set up. High speed photography is applied to confirm the validation of the technique. Both the photoes and the experimental strain waves show that sample was loaded only once.

In situ Raman spectra of cycloheptane have been characterized under high pressure generated by diamond anvil cell (DAC) at room temperature. The pressure is up to 17.00 GPa. With the increase of pressure, the cycloheptane experienced the liquid-solid phase transition at 0.53 GPa. During 3.45~5.58 GPa, both the curve of Raman frequence-pressure and FWHM-pressure presented inflexions, indicating a potential solid-solid phase transition of cycloheptane.

A new vertical shock tube was developed in order to investigate different stages of the development of hydrodynamic interfacial instability. The versatile shock tube permits the execution of three kinds of experiments on the turbulent mixing of fluids induced by the (1) Richtmyer-Meshkov instability at the gas-gas interface (initial perturbations are imposed on a thin nitrocellulose membrane), (2) Rayleigh-Taylor instability at the gas-liquid interface (acceleration of the contact boundary of different density fluids g₁≤2×10⁴ m/s²), and (3) combined Rayleigh-Taylor and Richtmyer-Meshkov instability at the gas-liquid interface (the first shock wave Mach number ranges from 1.05 to 2.5). The main benefits of such a facility are that it allows, first, to perform multiple experiments of interfacial instability and, second, to measure different transition phases from the beginning to the fully developed turbulent mixing stages.

Combined measurement with two or three different diagnostic systems in one shock-wave experiment, which could provide more information on high-pressure physical properties of materials and help people better understanding the nature of these properties, is the inexorable trend for the development of the shock-wave experimental technique. A combined diagnostic technique with multi-channel pyrometer and VISAR was primarily developed in two-stage light gas gun experiments. In one experiment, we successfully obtained spectral radiance histories and particle velocity profiles of LiTaO₃ sample by this technique, which indicated shock-induced luminescence and shock-induced phase transformation of LiTaO₃. The results show that combined measurement with pyrometer and VISAR is practicable for our shock-wave experiment.

Numerical investigation was carried out on a cylindrical shell subjected to deep water blast wave by using ABAQUS software package. The simulation contained static analysis by using ABAQUS/Standard and dynamic analysis by using ABAQUS/Explicit, and the analysis result of the former was imported into the latter as the initial condition, and then the influencing factors of dynamic response of cylindrical shell were identified. The calculated results indicated that the dynamic response of cylindrical shell was influenced by depth, orientation of explosion and prestress. The damage and distortion of cylindrical shell increases with depth, and the velocity-time history of cylindrical shell particle becomes smoother as the depth increases. The dynamic response to different orientations of explosion is distinct. Prestress leads to severe damage and distortion of the cylindrical shell, which also relates to orientation of explosion. Research results are valuable in evaluating the vulnerability of submarines.