高压物理学报

Experimental Study on Shear Response of Alumina Ceramic under Combined Compression and Shear Loading

DUAN Zhuo-Ping, YU Rui, ZHANG Lian-Sheng, HUANG Feng-Lei

2007, 21(4): 337-341 . doi: 10.11858/gywlxb.2007.04.001

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Abstract:
The pressure-shear plate impact experiments have been performed on 95% Al2O3 ceramic using 57 mm diameter compressed gas gun. The high-pressure gases drove the ceramic flyer to impact the oblique target to produce pressure-shear loading, and the particle velocity is traced by embedded electromagnetic velocity gauge. The inelastic behavior and shear wave propagation of ceramics under combined compression and shear loading have been probed in ceramic. The lateral particle velocities show an attenuation of shear waves with increasing of impact load. From the experiments, we found that when the compression stress reached about 4.86 GPa, 95% Al2O3 ceramic started to produce little amount of cracks and holes. The shear waves also began to attenuate.

The Sublimation Energy versus Temperature and Pressure and Its Influence on Gasifying Blow-off Impulse

TANG Wen-Hui, XU Zhi-Hong, NIU Jin-Chao, SHE Jin-Hu

2007, 21(4): 342-346 . doi: 10.11858/gywlxb.2007.04.002

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Abstract:
The dependence of the sublimation energy on temperature and pressure was studied based on universal thermodynamics. The result shows that the sublimation energy decreases linearly with the increasing temperature or pressure. The blow-off impulse of aluminum induced by pulsed X-ray was simulated by smoothed particle hydrodynamics (SPH) method, and the influence of sublimation energy on impulse was discussed. In contrast to the situation that sublimation energy is a constant, the numerical result shows that the blow-off impulse of aluminum will increase obviously if the change of sublimation energy with temperature and pressure is considered.

Investigation on Damage Characteristics of Thin Al-Plates by Oblique Hypervelocity Impact of Al-Sphere

GUAN Gong-Shun, HA Yue, PANG Bao-Jun

2007, 21(4): 347-353 . doi: 10.11858/gywlxb.2007.04.003

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Abstract:
The oblique hypervelocity impacts of space debris on bumper of spacecrafts were studied through 2017 aluminum spheres impacting on thin 2A12 aluminum alloy sheets at different angles. The penetration hole characteristics of single-wall shields and the ricochet characteristics of projectiles were analyzed. The equations for the hole size of oblique hypervelocity impact penetration into thin aluminum alloy sheets were derived. Impact velocities were 2.58 km/s, 3.56 km/s and 4.31 km/s respectively. Impact angles ranged from 0 to 80. The results indicated that the penetration hole size in thin aluminum alloy sheets depended on the impact velocity and impact angle. When an aluminum alloy sphere of 3.97 mm diameter impacted at hypervelocity on the thin aluminum alloy sheet of 1 mm thickness at different angles, the critical impact angle was between 30 and 40 in which projectile leaped away from the target partially. As impact angle increased, the maximum ricochet angle decreased, and the distributing area of ricochet debris cloud reduced. Impact velocity has little effect on the penetration hole ellipticity of thin aluminum alloy sheets under oblique hypervelocity impact.

Numerical Simulation of the Trace of Projectiles Penetrating Concrete

TIAN Zhan-Dong, LI Shou-Cang, DUAN Zhuo-Ping, ZHANG Zhen-Yu

2007, 21(4): 354-358 . doi: 10.11858/gywlxb.2007.04.004

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Abstract:
The continuum damage model which was originally developed to study rock fragmentation was implemented into the transient dynamic explicit finite element code LS-DYNA3D, and then the code is used for the numerical simulation of projectiles' penetrating the concrete. The possible traces of the projectiles in the target are investigated and the factors dominating the trace are found.

Effect of Eddy Current Waste on the Output Performance of the Explosive-Driven Ferromagnetic Generators

CHEN Lang, WU Jun-Ying, FENG Chang-Gen

2007, 21(4): 359-366 . doi: 10.11858/gywlxb.2007.04.005

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Abstract:
For increasing the output energy of the explosive-driven ferromagnetic generators, a new structure of ferromagnetic element has been designed to reduce the eddy current waste. The cylinderical Nd2Fe14B rare-earth magnet was cut into four separate parts, and the insulated layers were placed between magnet parts for keeping them insulating from each other. And then the four magnet parts with insulated layers were combined together again to form a new cylinder. The magnetic field calculations of the magnet cylinder and the cylinder with insulated layers were conducted by the Maxwell 3D code of the electromagnetic analysis software. The initial magnetic flux distribution of two types of cylinders were obtained. The detonation tests of ferromagnetic generators were carried out, and the electromotive forces of ferromagnetic generators were measured. The results show that the eddy current waste of the generator with insulated layers is lower than the generator without insulated layers, and the output energy of the former is higher than that of the latter.

Pressure Calibration for the Sample Cell of YJ-3000t Multi-Anvil Press at High-Temperature and High-Pressure

SHAN Shuang-Ming, WANG Ri-Ping, GUO Jie, LI He-Ping

2007, 21(4): 367-372 . doi: 10.11858/gywlxb.2007.04.006

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Abstract:
The pressure in the sample cell of YJ-3000t multi-anvil was calibrated in the temperature and anvil surface pressure ranges of 389~1 245 ℃ and 1.00~5.00 GPa by using the high-pressure melting curves of four metals: Cu, Al, Pb and Zn. Through the polynomial fitting of the calibration results for the four metals, we obtain a formula which is suitable for the experimental configuration in which the moderately fired pyrophillite and alumina were used as the outer and inner pressure-transmitting medium, respectively, and which can be used to calculate the practical pressure in the sample cell using the measured cell temperature and the anvil surface pressure reading. We hope that in future, the results obtained in the present work could provide a convenient and reliable pressure calibration for the sample cell of the similar experimental configuration in YJ-3000t multi-anvil at high-temperature and high-pressure.

Numerical Simulation of Particles Impact in Explosive-Driven Compaction Process Using SPH Method

ZHAO Zheng, LI Xiao-Jie, YAN Hong-Hao, Ouyang Xin

2007, 21(4): 373-378 . doi: 10.11858/gywlxb.2007.04.007

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Abstract:
Numerical simulation of large deformation using SPH meshless method has recently become a research hotspot. In this work, we used SPH of LS-DYNA to simulate particles impact in explosive-driven compaction process. Micro-jet flow and void collapse phenomena were mapped, supporting the theory of explosive-driven compaction. Additionally, Grneisen equation of state used in LS-DYNA code was obtained by the three-term equation of state and Rankine-Hugoniot relation.

Nano-Titanium Dioxide Synthesis Using Gaseous Detonation

Ouyang Xin, YAN Hong-Hao, LIU Jin-Kai, LI Xiao-Jie, QU Yan-Dong, DU Yun-Yan

2007, 21(4): 379-382 . doi: 10.11858/gywlxb.2007.04.008

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Abstract:
TiO2 nanoparticles are prepared by detonation method in gas phase. In this experiment, titanium tetrachloride is used as a precursor, and premixed gas (O2 and H2) as energy. Properties of TiO2 ultrafine particles were studied by means of XRD, SEM and TEM. The results show that the powders which are globose are rutile and anatase phase, and particle sizes of the powders are within 10 and 20 nm. There are also some larger particles which are about 100 nm. It is found that the production of larger particles is contributed to the deflagration to detonation course and the turbulent of detonation to grow. In the paper, the property of particles synthesized under the over-H2 and over-O2 case were compared. The result showed that the morphology of particles produced by the two cases does not vary greatly.

Motion History Measurement of Projectile Launched by a Two-Stage Light Gas Gun

PENG Qi-Xian, MENG Jian-Hua, LIU Shou-Xian, LIU Jun, CHEN Guang-Hua, MA Ru-Chao, LI Ze-Ren

2007, 21(4): 383-387 . doi: 10.11858/gywlxb.2007.04.009

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Abstract:
The work was done for the research of interior ballistic. A wide range fiber probe (depth of field is 13 m) was designed for measuring the motion history of projectile launched by a 32 mm two-stage light gas gun. The projectile velocity was measured by using a VISAR with velocity per fringe 100 m/s. The obtained result shows the projectile reaches a velocity of 3 960 m/s at the distance of 11.3 m, which is well consistent with the result from the magnetic measurement. The acceleration history of projectile was also obtained by differentiating the velocity profile. This work proved that the VISAR can been used in the interior ballistic research.

A Numerical Analysis for Pressure in Mixed Fuel during Launching

YAN Hua, ZHANG Qi, GUO Yan-Yi, ZHANG Yan-Chun, LUO Yong-Feng, WU Jin-Cai

2007, 21(4): 388-396 . doi: 10.11858/gywlxb.2007.04.010

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Abstract:
The launching safety of explosive charge drastically affecting the application of high explosive should be used with care. The researchers are interested in the low cost and high efficiency of FAE (fuel air explosive) charged warhead. However, few references about the launching safety of the mixed fuel, especially under high launching load, can be found. In this paper, the pressure and pressure-rate in the mixed fuel during launching was analyzed by the explosion mechanics programming Object MMIC. The analysis shows that the pressure and pressure rate are different from those obtained from the traditional launching safety theory. Therefore, it is necessary for FAE weapon to establish a new launching safety theory by means of the innovative method combining the pressure wave stage with the inertia stage.

LiF Window Corrections for VISAR

MA Yun, LI Ze-Ren, HU Shao-Lou, LI Jia-Bo, WANG Xiao-Song, CHEN Hong, WENG Ji-Dong, LIU Jun, YU Yu-Ying, SONG Ping, et al.

2007, 21(4): 397-400 . doi: 10.11858/gywlxb.2007.04.011

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Abstract:
Symmetric, plate-impact experiments were performed to measure LiF window correction coefficients for velocity interferometer system for any reflector (VISAR) (at 532 nm). Single crystal LiF window corrections for VISAR under shocked pressure from 2.7 GPa to 66 GPa and the methods of correcting interface velocity are presented.

Study on Synthesizing Diamond from Fe-Ni-C System at High Temperature and High Pressure

LI He-Sheng, LI Mu-Sen

2007, 21(4): 401-408 . doi: 10.11858/gywlxb.2007.04.012

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Abstract:
The synthesizing diamond experiment was carried out with iron-based catalysts made by powder metallurgy using industrial iron and nickel powder as stuff at cubic high pressure apparatus. By employing Raman spectroscopy and X-ray diffraction, it can be proved that the crystal gotten from the experiment whose grain size is 200~500 m is cubic diamond single crystal. The results of the mechanical property test indicate that the quality of diamond exceeds the standard of SMD25. By analysis, it can be judged that the process of diamond nucleation is the one that the molten alloy dissolves and catalyses the carbon atoms. Based on a lot of results, it can be illustrated that the carbon, which is needed for diamond growth, comes from the (Fe,Ni)3C under the absorption of -(Fe,Ni) and the film is not only the diffuse path of carbon, but also the catalysts of structure deformation.

Preparation of Cubic Boron Nitride Polycrystalline Containing Nanodiamond

ZHAO Yu-Cheng, SUN Jin-Feng, WANG Ming-Zhi

2007, 21(4): 409-413 . doi: 10.11858/gywlxb.2007.04.013

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Abstract:
The polycrystalline cBN was prepared at 5.5 GPa and 1 400 ℃ for 500 s. The cBN was coated with titanium by vacuum slow vaporizing technology, and nanodiamond, aluminum and silicon were also used as additives to binding components. By SEM and XRD inspections, the structure and phases of PcBN were identified. The density, microhardness and heat endurance of PcBN were also tested. The effects of Ti-coating and nanodiamond in PcBN were studied. The results showed that nanodiamond could be used as carbon source to react with silicon, titanium and aluminum to form various compounds with super hardness, high heat resistance and high stability. These compounds improved the structure consistency and eliminated the extra residual stress between different substances. The residual nanodiamond in PcBN was still in diamond structure, and was not graphitized during the sintering. It not only increased the density and hardness of PcBN, but also reduced the bridging effect. As there were so many kinds of compounds distributed in the binder, the compatibility was improved and the heat endurance of PcBN was increased.

A New Damage Model of Microvoids

DONG Jie, LI Yong-Chi, CHEN Xue-Dong

2007, 21(4): 414-418 . doi: 10.11858/gywlxb.2007.04.014

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Abstract:
With introducing the concept of the number of micro-damage in unit volume, macro damage parameter and microvoids volume are unified together, and a new kind of quadratic micro-voids damage evolution equation is acquired. The effect of inertia is considered during the expansion of voids. The expansion of surface and inertia will play a dominant role during the different stage of expansion of voids respectively. After taking the impact experiment of 921 steel as reference and comparing the curves of free surface velocity, the model is proved to be correct since their results are matched well.

Experimental Study on Penetration Resistance of Soil with Low-Velocity Projectile

DONG Yong-Xiang, FENG Shun-Shan, LI Yan-Dong, LI Xue-Lin

2007, 21(4): 419-424 . doi: 10.11858/gywlxb.2007.04.015

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Abstract:
The ballistic characteristics and penetration depth in the different soil media with vertical attitude are obtained by experiments of the low velocity projectile penetrating into hard soil, mid-hard soil and mid-soft soil. Further, the nondimensional equation on penetration depth in different soil media with the projectile dynamic pressure is fitted by test results. Based on the different penetration features with low velocity projectile penetrating the different soils in the paper, the penetration resistance of different hard or soft soil and the penetration characteristics of projectile can be calibrated effectively. Comparing with the experimental results, it is verified that Young penetration equations can be applied to the condition of penetration depth less than three times of projectile diameter.

Factors Analysis of Debris Cloud's Shape of Hypervelocity Impact

TANG Mi, BAI Jing-Song, LI Ping, ZHANG Zhan-Ji

2007, 21(4): 425-432 . doi: 10.11858/gywlxb.2007.04.016

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Abstract:
The numerical simulations of hypervelocity impact of Al-spheres on bumper at normal are carried out using the smoothed particle hydrodynamics (SPH) technique. The simulation results are compared with experimental results, and the simulated hole diameters of bumper and debris cloud are well consistent with experimental results. The effect of impact velocity, bumper thickness, projectile diameter, materials, shape of projectile, interval on produced debris cloud are further analyzed. Regarding the length and diameter as index, orthogonal design method is applied to analyze the primary and secondary relations on the debris cloud's index of the three factors, that is impact velocity, bumper thickness and projectile diameter. The results indicate that bumper thickness is the main influence factor of debris cloud's length while projectile diameter is the main influence factor of debris cloud's diameter.

Phase Transformation Mechanism of Single Crystal Iron from MD Simulation

CUI Xin-Lin, ZHU Wen-Jun, HE Hong-Liang, DENG Xiao-Liang, LI Ying-Jun

2007, 21(4): 433-438 . doi: 10.11858/gywlxb.2007.04.017

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Abstract:
Shock-induced phase transformation (body-centered cubic phase to hexagonal close-packed phase) in single crystal iron has been investigated by means of molecular dynamics (MD) simulations using an embedded atom method (EAM) potential. The simulated dimension is 28.7 nm22.9 nm22.9 nm in size with 1.28106 atoms. The shock wave is generated by using a piston impact on the sample along the [100] direction. By analyzing the motion history of atoms under shock compression, the phase transformation mechanism has been outlined. The simulation results show that the phase transformation mechanism contains two steps: the atoms on the {011} planes are compressed along the 〈100〉 direction to form a hexagon in the first step, and then the atoms on {011} planes in the 〈0-11〉 direction are slipped to create the hcp structure in the second step. The results also show that the slip planes are only the (011) and (0-11) planes which are parallel with the shock wave propagation.

Effect of the Preheated Flyer on Hugoniot Measurements

WANG Qing-Song, LAN Qiang, DAI Cheng-Da

2007, 21(4): 439-443 . doi: 10.11858/gywlxb.2007.04.018

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Abstract:
A theoretical method was proposed to evaluate the Hugoniot parameters of the preheated metals based on Grneisen equation of state. This method offsets some disadvantages of BACT and can be used to estimate Hugoniot parameters of all kinds of solids with preheating in principle. This method was applied to calculate the Hugoniot parameters for Al and TC4 at different initial temperatures up to 1 200 K and compared the obtained results with the available data reported in literature. It is shown that the moderate preheating of metal does not result in an obvious deviation from its principal Hugoniot. Thus the rough treatment in hypervelocity impact experiments that the Hugoniot of preheated flyer is approximated to be the principal Hugoniot is reasonable.

Several Internal Heating Modes and Temperature Measurement in Bridgman Anvil

LIU Xiu-Ru, Lü Shi-Jie, SU Lei, SHAO Chun-Guang, HU Yun, HUANG Dai-Hui, HONG Shi-Ming

2007, 21(4): 444-448 . doi: 10.11858/gywlxb.2007.04.019

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Abstract:
Four internal heating modes in Bridgman anvil were designed in this work. Heater was made of tantalum and graphite flakes. Two thermocouples were used to measure the temperature change of the central and upside section in sample cavity with input voltage. Temperature gradients were roughly discussed. Under 0.1 GPa, highest temperature reached in sample cavity was higher than 1 300 ℃. In addition, sample temperature change with input voltage was also measured up to 1 000 ℃ under 5.0 GPa.

2007 Vol. 21, No. 4

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