高压物理学报

Experiments and Numerical Simulations of Bullet Impact Tests for Explosives with Shell

WU Jun-Ying, WANG De-Wu, CHEN Lang, WANG Shu-Shan, HAN Xiu-Feng

2010, 24(6): 401-408 . doi: 10.11858/gywlxb.2010.06.001

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Abstract:
HL-10 explosive is an aluminized explosive based on RDX. In order to investigate the safety characteristics of HL-10 for bullet impact test, 12.7 mm bullet was used to impact HL-10 charge. Experimental results show that there is no significant reaction or burning resulted from these bullet impact tests, so the impact sensitive of HL-10 for bullet impact test is defined as the first grade. The calculation modes and methods of bullet impact tests were established. The three-dimensional numerical simulations of the bullet impact tests were conducted. Good agreement was found between the calculated results and the experimental results. In addition, the responses of HL-10 to different bullet impact velocities were analyzed. The calculated results can provide a theoretical basis for the analysis of explosives safety evaluation. To further verify the calculation model and method, the bullet impact test calculation for America PBX-9404 explosive was conducted. The results show that, PBX-9404 explosives would be detonated at 850 m/s impact velocity for the same calculation mode, which are consistent with Neff and others experimental results.

Acoustic Emission Dynamic Characteristics of Growth Process of Diamond Single Crystals under HPHT

LIU Lei, ZHANG Yuan-Pei, WANG Feng, CHEN Chong, LI Mu-Sen

2010, 24(6): 409-414 . doi: 10.11858/gywlxb.2010.06.002

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Abstract:
The growth process of synthetic diamond single crystals under high-pressure and high-temperature (HPHT) was tested with acoustic emission technique. Associated with the fracture morphologies of the synthetic mass, the main acoustic emission dynamic parameters corresponding to growth process of diamond single crystals were analyzed. The results indicate that the energy, count, amplitude and rise time of recorded acoustic emission signals can be objective reflection of the dynamic growth process of diamond single crystals under HPHT. The research provides the important experimental basis for studying the in-situ reaction mechanics of synthetic diamond single crystals under HPHT by using acoustic emission testing.

Numerical Simulations on the Thrust Performance of Nozzles and Detonation Propulsion of a Sudden Area Change Tube

ZHANG Huan-Hao, CHEN Zhi-Hua, SUN Xiao-Hui, FAN Bao-Chun

2010, 24(6): 415-422 . doi: 10.11858/gywlxb.2010.06.003

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Abstract:
Based on the homogenous fluid reaction N-S equations, the k- turbulent model and the EBU combustion model, the propagation of detonation wave in a sudden area change tube and the influences on the thrust performance of the main tube with different nozzles were investigated. Our results show that, a new detonation can be initiated promptly when the detonation wave of the pre-detonator injects into the main tube. In addition, with the mount of nozzle, the average thrust of single detonation varies. The head-end thrust increases with the raise of the contracting angle of nozzle, and decreases with the raise of its diverging angle. But the average total thrust increases with the diverging angle, and decreases with the raise of converging angle. There also exists an optimal diverging angle which can generate maximum average total thrust.

Investigation into Charge Height Ratio of Micro-Detonator on the Output Detonation Pressure

HE Ai-Jun, YAN Nan, FU Shu-Ling, GENG Wan-Jun

2010, 24(6): 423-430 . doi: 10.11858/gywlxb.2010.06.004

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Abstract:
In order to accommodate to the needs of micro-explosive train in MEMS fuze, this paper carried out a specific study about the influence of charge height on the output detonation pressure in micro-detonator. The charge diameter is 0.9 mm, total height is 3 mm. The charge ratio of primary explosive and high explosive was to be changed. The output detonation pressure was measured by manganin piezoresistance method. In the micro-detonator, the critical height of primary explosive PbN6 is 0.36 mm. When the primary explosive PbN6 height is 1.65 mm, the micro-detonator has the maximal output detonation pressure 10.3 GPa. When the primary explosive PbN6 height is less than or more than 1.65 mm, the high explosive HMX height is less than or more than 1.35 mm, and the output detonation pressure of the micro-detonator is reduced. The range of the primary explosive PbN6 and the high explosive HMX is 0.69～2.26.

Study on the Shock Wave Attenuation of the Booster Charge in the PMMA Gap

XU Sen, LIU Da-Bin, PENG Jin-Hua, WANG Jian-Ling, GUO Wei, JIN Peng-Gang, JIA Xian-Zheng

2010, 24(6): 431-437 . doi: 10.11858/gywlxb.2010.06.005

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Abstract:
The shock pressure at the interface between booster charge and PMMA gap was calculated by graphing method. The AUTODYN was used to simulate the attenuation process of the shock wave in the PMMA gap. The output shock pressures, which were produced by the substituted booster charge of the UN gap test, were measured in the PMMA gap at different positions by manganin gauges. The shock velocity, particle velocity and density after the shock front were calculated. The results showed that the measured data, theoretical arithmetic and numerical simulation are consistent, and the attenuation regularity of shock pressure in PMMA is extracted from the test results. AUTODYN 6.1 software is capable of predicting the attenuation characteristic of shock wave in PMMA gap.

Study on the Agglomerate Structures of TiO2 Nanoparticles

QU Yan-Dong, LI Xiao-Jie, LIU Yuan

2010, 24(6): 438-442 . doi: 10.11858/gywlxb.2010.06.006

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Abstract:
The short duration of high temperature and high pressure during the detonation process made the TiO2 nanoparticles not have enough time to grow into large and fine crystallites and only generate a large number of spherical-like nanoparticles. The rapid interactions between these formed TiO2 nanoparticles (such as collision, friction, extrusion, infiltration and adhesion) could easily form agglomerate structures in the humid detonation gas environment. The agglomerate structures and dispersion morphologies of the TiO2 nanoparticles prepared by detonation method using titanium titanyl sulfate as TiO2 source were studied. In order to reveal the influence of heat treatment on the agglomeration properties of the TiO2 nanoparticles, the agglomerate structures of the TiO2 nanoparticles via heat treatment at 500 ℃ for 1 h were also analyzed. Research showed that the soft and hard agglomerates of the TiO2 nanoparticles were formed and that the agglomerate structures of the TiO2 nanoparticles after heat treatment could be improved to some extent. The influences of nanoparticle characteristics, detonation characteristics and detonation gas environment on the formation of the agglomerate structures of TiO2 nanoparticles were also discussed.

Research on Pyrotechnic Composition Combustion Underwater and Its Effective Acting Time

OUYANG De-Hua, GUAN Hua, PAN Gong-Pei, DU Xue-Feng, XIAO Gui-Lin

2010, 24(6): 443-448 . doi: 10.11858/gywlxb.2010.06.007

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Abstract:
The defining of effective acting time for pyrotechnic composition combustion underwater was put forward. The main problems of current methods for testing and processing the acoustic radiation characteristics of pyrotechnic composition combustion underwater and explosion underwater were analyzed. And then, based on Pulse Labshop software platform and experimental results, the effective acting time for pyrotechnic composition combustion underwater was obtained, with graphic slicing technique. This new method can be used to assess the effective acting time of pyrotechnic composition combustion underwater and explosion underwater sound source, and so on. It also provides a reference for the engineering application and performance evaluation.

First-Principles Calculation of ZnS Doped with Mn or Fe

LI Sheng-Zhi, LIU Jin-Chao, YANG Xiang-Dong, GUO Yan-Feng, XU Hai-Quan

2010, 24(6): 449-454 . doi: 10.11858/gywlxb.2010.06.008

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Abstract:
The electronic structure and optical properties of pure and Mn-doped or Fe-doped zinc blende ZnS were calculated by first-principles ultra-soft pseudopotential approach of the plane wave based upon the density functional theory, and the band structure, density of states and optical absorption properties were studied. The calculated results show that the density of states near Fermi energy level is derived from Mn 3d and Fe 3d states. Moreover, the optical absorption spectrum shows an obvious red shift, also extends to lower energy side and generates a new peak of optical absorption at the low-energy side after doping with Mn and Fe.

Magnetically Driven Quasi-Isentropic Compression Experiments of Solid Explosives

CAI Jin-Tao, WANG Gui-Ji, ZHAO Jian-Heng, MO Jian-Jun, WENG Ji-Dong, WU Gang, ZHAO Feng

2010, 24(6): 455-460 . doi: 10.11858/gywlxb.2010.06.009

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Abstract:
It is very important and instructive for us to further and accurately investigate the interaction between constitutes of explosive and formation mechanism of hot spots in explosive initiation, with the constitutive relation and equation of states in wide pressure zone. Compared with shock compression, magnetically driven quasi-isentropic compression (shockless compression) is a more effective method to research the dynamic behavior of un-reacted explosives in wide pressure zone. Based on the working principle of electro-magnetic force produced by large current, the shockless compression technique driven by magnetic force was first realized in domestic. By optimizing the loading electrodes and the parameters of explosive samples, and controlling the installation technology, a pressure of 5 GPa was realized in magnetically driven quasi-isentropic compression experiments. By means of the technique of laser displacement interferometer and the Lagrange data processing method, the particle velocities of the interface between JO-9159 explosive and LiF windows were measured, and from which the experimental isentropes of JO-9159 explosive were obtained. Compared with the results from references, the experimental isentrope of JO-9159 explosive is consistent with that of PBX9501 explosive.

Texture and Structural Defect Evolution of Pure Nickel Subjected to High-Current Pulse Electron Beam Irradiation

LI Yan, GU Qian-Qian, QIU Dong-Hua, PENG Dong-Jin, GUAN Qing-Feng

2010, 24(6): 461-466 . doi: 10.11858/gywlxb.2010.06.010

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Abstract:
The specimens of polycrystalline nickel were irradiated with high-current pulsed electron beam (HCPEB). Surface textures and structural defects of irradiated nickel were investigated by using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD results show that the characteristics of preferential orientation {111} and {200} are presented after HCPEB treatments. While the treating pulses were chosen as 1 and 5 times, the surface microstructure changes after irradiation was analyzed by TEM. Within the surface layer the (111) [112] type of wave shear bands are formed in the interior of grains. Large numbers of (200) [110] types of micro-bands parallel each other embed in the wave bands. After 10 pulses, the deformation structure changed prominently. Besides the wave bands, the number of deformation twins increase evidently. The formation of these deformation structures has a significant effect both on the evolution of surface textures and grains refinement. It is suggested that HCPEB technique is becoming an effective approach to fabricate surface nanocrystalline materials.

Technique for Measuring Transmittance of Optical Windows under Dynamic Loading and Its Application

LI Yong-Hong, LIU Fu-Sheng, CHENG Xiao-Li, MA Hai-Yun, ZHANG Ming-Jian, XUE Xue-Dong

2010, 24(6): 467-471 . doi: 10.11858/gywlxb.2010.06.011

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Abstract:
A measurement technique for optical transmittance of window material under gas-gun-driven shock loading condition was developed, in which a pulsed light source of semiconductor laser was mounted in the projectile and along its central axis to measure the transmittance change of transparent sample during loading and unloading processes. The advantages of the light source over the traditional xenon-lamp are: (1) the work voltage is only 4.5 V; (2) the response time is less than 500 ns; (3) the output power is stable. The improved method provides an important tool for studying the transparency change, absorption, and failure of brittle materials. Quartz glass, as an example, is found to partially lose its transparency during the unloading process after shock compression of 1.8 GPa, and the decrease of transmittance is as high as 30%. The results do not support the explanation of liquid-solid phase transition given by literature.

Effect of High Hydrostatic Pressure on Starch Structure and Gelatinization

LIU Pei-Ling, ZHANG Fu-Sheng, BAI Yun-Fei, HU Xiao-Song, SHEN Qun

2010, 24(6): 472-480 . doi: 10.11858/gywlxb.2010.06.012

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Abstract:
While most current studies of high hydrostatic pressure are for starches, there is evidence that high pressure can induce modification and gelatinization of some starches. Over 25 starches were investigated by high hydrostatic pressure. Different starches respond differently to applied high pressure, depending on the pressure range, starch source, temperature, solvent concentration and so on. Possible mechanisms for pressure-induced changes were discussed and compared with current starch analytical techniques. The compiled evidence of high-pressure starch enhancement in this review indicates that the treatment by high hydrostatic pressure is a potentially effective way to improve the quality of starches.

2010 Vol. 24, No. 6

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