In-situ high-pressure Raman study of the gypsum was carried out from 0 to 35 GPa with a diamond anvil cell (DAC). The authors determined the pressure dependences of the Raman bands of gypsum. A new Raman peak 1 012 cm^-1 in the stretching vibration of range is found at pressure of about 4.5 GPa, and its intensity is shown to strengthen with increasing pressure. So we can determine the occurrence of pressure-induced phase transition near 4.5 GPa.

The n-type nonstoichiometric PbTe(Pb_0.55Te_0.45) materials were prepared by the high pressure sintering process. The emphasis of the present study is on the influence of the pressure on the thermoelectric properties of the material. The experimental results show that the lattice defects are removed by high pressure sintering process, and it effectively adjusts the carrier concentration and its transport properties. Compared with the melting ingots, the Seebeck coefficient of the high pressure sintering sample obtains enhancement largely, the electric conductivity slightly reduces, simultaneously the thermal conductivity is low, and therefore the figure of merit (Tα²σ/κ) of the high pressure sintering sample is greatly enhanced. Therefore, the maximum the figure of merit of the sample prepared by 2 GPa reaches 0.59 at 700 K, which is about 150% improvement in comparison with the melting ingot.

Stainless steel mesh/Al multi-shock shield was designed by improving Al Whipple shield, and a series of high-velocity impact experiments were conducted by a two-stage light gas gun facility. Impact velocities of Al-spheres varied between 3.93 km/s and 4.25 km/s. The diameter of projectiles was 6.35 mm. For the different shield configurations with the same stainless steel mesh, the same shield configurations with different stainless steel mesh and the filmed stainless steel mesh shield configurations, the structure and material factors affecting on performance of shield were analyzed. The results indicated that when the stainless steel mesh wall was located in the last wall site of the bumper, it could help dispersing debris clouds, reducing the damage of the rear wall. At the same time, when the stainless steel mesh wall was located in the first wall site of the bumper, it did not help comminuting and decelerating projectile. The mesh opening size, wire diameter and separation distance arrangement were the important factors to enhance the protection performance of shields. The filmed stainless steel mesh helped in weakening the kinetic energy of debris cloud.

Numerical simulation for the temperature distribution in sample assembly of cubic press was carried out by using the finite-element method with simplified model and boundary conditions. Based on the adjustment of parameters of the models in simulation, the temperature distribution induced by pressure transmission media, shapes of heater and conductive metal ring were discussed in details. The results indicate that the use of zirconia instead of pyrophyllite as the buffer and thermal insulator can elevate the temperature and at the same time lower the thermal gradient in sample area while reducing power consumption. Different shapes of heater will affect on the temperature distribution. In the case of the metal ring being used in assembly, properly increasing the thickness of the ring will be beneficial to obtain desirable temperature distribution. This work could be a useful reference to optimize the design of sample assembly in cubic press for high temperature and high pressure experiments.

The thermoelectric properties of PbTe nanoparticles were studied from ambient pressure to 0.8 GPa by using self-built set-up. The electrical conductivity increased while Seebeck coefficient decreased with loading pressure and these properties can be recovered after pressure released. Moreover, Seebeck coefficient is extremely high, up to 565 μV/K at ambient pressure. At 0.8 GPa, the electrical conductivity enhances four times, the power factor adds three times and Seebeck coefficient is only reduced by 20% comparing with those at ambient pressure. These results indicate that high pressure can improve the thermoelectric properties of PbTe nanoparticle. The contracted Femi-energy is also calculated based on the First Principle under high pressure from 0.4 to 4.0 GPa. The calculated values agree well with experimental data.

Dynamic Brazilian test of plastic-bonded explosives was investigated by split Hopkinson pressure bar (SHPB). The tensile strengths of three PBXs were acquired under different strain rates. The evolution of crack on sample surface was captured using high-speed camera. The strain field was calculated by digital speckle correlation method before samples occured to crack. The simulation on dynamic Brazilian test was performed using discrete element method, and the simulation model considering meso-structure was acquired. The simulation results show the produce and evolution process of damage and crack, and the simulation results are in accordance with the experimental results.

A loading test by explosive rods to simulate mechanical effects of pulsed X-ray was numerically simulated by fluid-structure interaction method. The 2-D numerical model including a cylindrical shell, two layers of rubbers, nineteen explosive rods and a layer of air was built. Therein, the two rubber materials were described by Ogden hyperelastic models, the explosive rods and their explosion product were described by High Explosive Burn model and JWL equation of state, and the air was described by polynomial equation of state. The numerical simulation was performed by the multi-material ALE method. The physical images, load transmission and structural responses were obtained. The results show that, in the loading test of 265 mm cylindrical shell by 19 explosive rods to simulate a cosine-distributed load induced by X-ray, the stress responses at typical locations are basically equivalent. Furthermore, the additive two rubber layers can affect the response characteristics of the shells, and tightly glued interactions can distort the structural responses of shells with small mass and/or low stiffness.

Steel plates are widely used to construct resistant structures, and a lot of literature report on the ballistic resistance of metallic monolithic target. However, few reports can be found for double-layered target (DLT), especially the one with large gap space. Experimental study was conducted on the DLTs of both in contact (I-DLT) and with 200 mm gap space (S-DLT) by using a gas gun to fire blunt projectiles. Each DLT was made of two A3 steel plates with the thickness of 5 mm. From the experiments, initial-residual velocity curves were obtained. The experimental observations are as follows. Firstly, both configurations of DLT suffer from shear plugging. Secondly, the ballistic limit of I-DLT is 1.92 times of that of 5 mm thick monolithic target. Thirdly, the ballistic resistance of S-DLT yield to large divergence. The large divergence, according to the high speed photograph and the recovered targets, is caused by the two classical different trajectory statuses of the projectile after perforation of the first plate. Fourthly, there are two ballistic limits for S-DLT. Finally, the ballistic limit of I-DLT is close to or greater than that of S-DLT. Parallel numerical simulations were conducted by ABAQUS/EXPLICIT, and the experimental phenomena and results were well predicted.

The initial yield behavior of Alporas closed-cell aluminium foams with relative density 8.5% under biaxial loading has been experimentally investigated using the Arcan apparatus and the universal testing machine (INSTRON 5544). The experimental yield surfaces measured from biaxial experiments are compared with various proposed phenomenological yield surface models. The comparison result indicates that the experimental data are consistent with both Miller and Deshpande and Fleck criteria. Biaxial experiments have been carried out on aluminium foams at various loading velocities to study the effect of strain rate on the initial yield surface. The results showed that the initial yield stresses of Alporas closed-cell aluminium foams are not sensitive to the equivalent strain rate ranged from 7.0×10^-3 s^-1 to 1.0×10^-1 s^-1.

According to characteristic of secondary debris, initial models of secondary debris are built. The models of secondary debris are classified as three patterns. The first patten is that the projectile is not fragmentated. The second patten is that the projectile is not entirely fragmentated. The third patten is that the projectile is entirely fragmentated. The secondary debris deceleration process is analyzed based on hydrodynamics theory and gas-solid two phase flow theory. The computational model of secondary debris deceleration is built. The computational results are consistent with numerical results very well. The model of secondary debris deceleration is validated.