高压物理学报

Stress Analysis on Hinge Sleeve and Cylinder of China-Type Cubic-Anvil High Pressure Apparatus under High Pressure

ZHANG Cong, MA Hong-An, HAN Qi-Gang, LI Zhan-Chang, JIA Xiao-Peng

2010, 24(5): 321-325 . doi: 10.11858/gywlxb.2010.05.001

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Abstract:
The contact analysis of hinge sleeve, cylinder and dowel in China-type cubic-anvil high pressure apparatus were conducted by finite element method and ANSYS. To avoid excessive similarity and supposition for ear and obtain exact simulation results, the fixing dowel, whose movement is constrained, was introduced in the model. The results indicated that the peak values of von Mises stress in hinge sleeve and cylinder are located within the inner ear and the bottom of cylinder, respectively, and the corresponding calculated maximum von Mises stresses are 348.32 MPa and 242.87 MPa, respectively, which are lower than allowable stress of 486.67 MPa. These results have been verified by numerous experiments.

Molecular Dynamics Simulation of Uniaxial and Adiabatic Compression of -HMX Crystal

SHI Yi-Ding, HUANG Feng-Lei

2010, 24(5): 326-332 . doi: 10.11858/gywlxb.2010.05.002

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Abstract:
The uniaxial compression of -HMX crystals in three orientations of (100), (010) and (001) were calculated through molecular simulations using COMPASS (Condensed-Phase Optimized Molecular Potential for Atomistic Simulation Studies) force field. The isotherms of the three orientations are different, which indicates that the -HMX has anisotropic compression property. The adiabatic hydrostatic compressions of -HMX were also simulated in NpH ensemble. The adiabat is above the isotherms and in better agreement with the shock experiments. The temperatures of -HMX were simulated by molecular dynamics and compared with the shock temperatures of -HMX calculated with approximation theoretical method. Although there were some small deviations between the simulated and the calculated shock temperatures, the simulation of compression of -HMX crystals in NpH ensemble is suitable for predicting the shock temperature of -HMX explosive. COMPASS force field is applicable to describe the adiabatic compression of -HMX. The simulation of adiabatic compression of explosive using molecular dynamics can predict the shock temperature of explosive.

Experimental Research on Propergation of Failure Wave in Glass

ZHANG Yan-Geng, DUAN Zhuo-Ping, ZHANG Lian-Sheng, OU Zhuo-Cheng, HUANG Feng-Lei

2010, 24(5): 333-337 . doi: 10.11858/gywlxb.2010.05.003

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Abstract:
Planar impact experiments of soda-lime glass were conducted on a 57 mm diameter one-stage gas gun, in which the free surface particle velocity histories for several different thicknesses of soda-lime glass under the same impact loading were measured by using VISAR (Velocity Interferometer System for Any Reflector). Both the failure wave velocity and the failure wave trajectory were obtained. The experimental results showed that there is a time delay for the failure wave to form on the impact surface of the soda-lime glass, which decreases with the magnitude of the impact load. The present study plays an important role in further understanding of the formation mechanism and propagation law of failure wave in brittle materials.

Influence of B4C Content in the Iron-Based Catalyst on the Apparent Activation Energy of Boron-Doped Diamond Single Crystals

ZHANG Yuan-Pei, LI He-Sheng, TIAN Bin, QI Yong-Xin, LIU Lei, LI Mu-Sen, 

2010, 24(5): 338-342 . doi: 10.11858/gywlxb.2010.05.004

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Abstract:
The boron-doped diamond single crystals with different boron amounts were synthesized by adding B4C in iron-based catalyst. Based on the testing data of different thermal analysis (DTA) and thermal gravity (TG) analysis during heating process, the apparent activation energies were calculated by the Kissinger method. The effect of different boron amounts on their thermal stability and oxidation resistance were analyzed in oxidation reaction. The experimental and theoretical results showed that the variation trends of the DTA and TG are consistent with that of the apparent activation energy. In the severe oxidation process, both the thermal stability and the oxidation resistance of the boron-doped diamond single crystals increase firstly and then decrease with the increasing of boron amounts.

Dynamic Response Characteristics of Ship-Like Beam Subjected to Underwater Explosion in Near Field

ZHU Xi, LI Hai-Tao, MU Jin-Lei, HUANG Xiao-Ming

2010, 24(5): 343-350 . doi: 10.11858/gywlxb.2010.05.005

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Abstract:
To study dynamic response and overall damage modes of warship subjected to underwater explosion in near field, a ship-like model was designed based on similarity criterion. The dynamic response was investigated by changing stand-off and weight of explosive in experiments where four kinds of explosives were located closely under the mid-span of the hull girder. In experiments, high-speed photography was applied to obtain the girder's movement process. Simultaneously, the data of strain and acceleration was attained to make a detail analysis on how the object reacts against shock wave and bubble. Experimental results show that there exits a low-pressure fluid zone below the girder due to bubble pulse in near field. The low-pressure area makes the girder undergo a vertical bending moment and possibly suffer an overall bending damage. With the increase of stand-off, the relevance of explosion energy and damage effect gradually increases. If stand-off is close to the maximum bubble radius, the bubble will exert a maximum damage effect on the structure.

Research on the Effect of the Projectile Penetrating into the Reinforced Concrete Targets at the Intersection of the Steel Bar

MU Chao-Min, REN Hui-Qi

2010, 24(5): 351-358 . doi: 10.11858/gywlxb.2010.05.006

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Abstract:
Considering direct interaction of the projectile with the steel bar, the approximate model of the projectile penetrating into the reinforced concrete is established. Using this model, the acceleration-time history is obtained. Calculation data are in agreement with experimental data. The model is used to analyze the effect of steel bar size, steel bar mesh size and steel bar configuration on the penetration depth and the overload effect in penetration process. The results indicate that when the projectile penetrates into the reinforced concrete targets at the intersection of the steel bar, the steel bar mesh size and steel bar size have an important influence on the penetration; when the projectile has small kinetic energy, the first layer of steel consumes most of kinetic energy. On the other hand, no matter how much the steel bar mesh size is, part of kinetic energy is used up by the first layer of steel when the projectile has large kinetic energy.

PVDF Stress Gauges Dynamic Stress Measurement and Its Application to SHPB Experiment for Rubber Materials

PANG Bao-Jun, YANG Zhen-Qi, WANG Li-Wen, CHI Run-Qiang

2010, 24(5): 359-367 . doi: 10.11858/gywlxb.2010.05.007

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Abstract:
Dynamic calibration experiments of sandwich PVDF (Polyvinylide Fluoride) stress gauges have been investigated by split Hopkinson pressure bar (SHPB). Dynamic piezoelectricity of PVDF gauges has been discussed, including testing circuit, stress concentration effect of PVDF gauge surface, inherent characteristic and package of PVDF stress gauges and multi-impact effects on the testing signals. The stress uniformity state of rubber materials has been investigated by PVDF gauges. The results show that adjusting the testing resistance can improve the accuracy; increasing the PVDF gauge sensitive area can avoid the signal distortion caused by stress concentration; thermal-plastic characteristic and gauge package can cause the PVDF stress plate to vibrate less than real signal; multi-impact has influence on both the signal loading and unloading part, but when the gauge is un-damaged, the signal flat potion is similar to the real signal.

Experimental Study on Explosive Compaction of W-Cu Nanocomposites

LI Xiao-Jie, WANG Zhan-Lei, YAN Hong-Hao, WANG Xiao-Hong, ZHANG Yue-Ju

2010, 24(5): 368-372 . doi: 10.11858/gywlxb.2010.05.008

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Abstract:
Explosive compaction was used to fabricate dense W-Cu composites in a cylindrical configuration/single tube set-up, and the highest density of the compacts reached 98%. The W-Cu alloy powders produced by mechanical alloying were analyzed by X-ray diffraction (XRD). The effect of reduction temperature of the powder mixture on density was studied. Using electron probe micro analyzer (EPMA) and scanning electron microscope (SEM), the distribution of elements and fracture surface morphology were observed and analyzed. The hardness and conductivity were also measured. The results showed that the W-Cu alloy powders compacted by explosive are transformed into the high-density nanocomposites, which demonstrated the characteristics of high hardness, uniform structure and fine grain.

The Dynamics Effect and Material Parameters of Polyester Radiated by Electron Beam

TANG Wen-Hui, CHEN Hua

2010, 24(5): 373-376 . doi: 10.11858/gywlxb.2010.05.009

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Abstract:
The dynamics effect of polyester under electron beam radiation is studied. The energy deposition of electron beam in polyester is calculated by Monte Carlo methods. The thermal shock wave propagation and the blow off impulse of polyester are simulated by the hydrodynamic method. From the comparison between simulation and experimental results of blow off impulse and peak pressure of thermal shock, the obtained cohesive energy of polyester is about 1.1 kJ/g, and the value of Grneisen parmeter at standard state is about 0.2.

Simulation Analysis on Law of Penetration of Long-Rod Projectiles with High Speed into Concrete

LIAN Bing, JIANG Jian-Wei, MEN Jian-Bing, WANG Shu-You

2010, 24(5): 377-382 . doi: 10.11858/gywlxb.2010.05.010

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Abstract:
Using the AUTODYN-2D software, penetrations of long-rod projectiles into semi-infinite concrete target at an impact speed of 0.6～2 km/s were simulated, in which materials, masses and length-to-diameter ratios of projectiles are different. The effects of impact speed on penetration depth and hole diameter were analyzed. The results show that hole diameter increases with the impact speed. There is a noticeable inflection point of penetration depth. The effect of material, mass and length-to-diameter ratio on inflection point of penetration depth was further studied. The material has a huge impact on inflection point of penetration depth, while mass and length-to-diameter ratio have a little impact on inflection point of penetration depth.

Simulation on Head-on Bulging Dynamic Behavior of Lead Flyer with SPH Method

YUAN Shuai, HU Hai-Bo, ZHANG Chong-Yu, LI Ping

2010, 24(5): 383-387 . doi: 10.11858/gywlxb.2010.05.011

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Abstract:
Using the smoothed particle hydrodynamics (SPH) method, the dynamic behavior of assembly flyers (Al+Pb) driven by cylindrical explosive ignited at two opposite points of the surface was simulated numerically. The calculated images for the generation and evolvement of jet-like bulge of lead sample at collision zone were obtained. The bulge emerges multi-layer structures observed in the simulated graphs, which consist of scatter fragments in the head and relatively condense structure in the rear, are in agreement with the experimental results. Accordingly, the SPH method can well deal with the failure of the metals with low melting point and low strength in the counter strike region, such as lead.

Investigation on Applicability of Shock Similar Law for Underwater Explosion of Aluminiferous Explosive

ZHAO Ji-Bo, TAN Duo-Wang, LI Jin-He, GONG Yan-Qing, SUN Yong-Qiang

2010, 24(5): 388-394 . doi: 10.11858/gywlxb.2010.05.012

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Abstract:
Aiming at the notable non-ideal characteristic of aluminiferous explosive, applicability of shock similar law at underwater explosion far-field is explored. Experiments are carried out in the blast-pond, in which pressure sections of shock wave are tested at different distance to charge center. Peak pressure and time constant are obtained. Combining dimension analysis and characteristic of aluminiferous explosive, applicability of shock similar law is discussed. It is shown that energy produced by the reaction of aluminum power and detonable production should be eliminated, while shock similar law is applied to aluminiferous charge.

Study on Nanometerization of Titania Grain during Transformation under Planar Shock Wave

LI Hou-Shen, YANG Shi-Yuan, XIANG Yun, CAI Ling-Cang, WANG Jun-Xia

2010, 24(5): 395-400 . doi: 10.11858/gywlxb.2010.05.013

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Abstract:
The anatase powders and TiO2 xerogel powders prepared by the sol-gel method were impacted under planar shock wave. The powders after impact wave loading were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and laser particle size analyzer (LPSA). The results showed that the metastable anatase form of TiO2 can be transformed into stable rutile under the high temperature effect of the shock wave, and the phase change of the TiO2 xerogel powders to the rutile phase is more accessible than that of the anatase powders. The short duration of shock wave can inhibit the growth of grain and achieve nano-grains. The high pressure process can effectively control agglomeration as the result of the sol-gel method.

2010 Vol. 24, No. 5

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