高压物理学报

High Pressure Induced Transformations in One-Dimensional Carbon Nanomaterials

YAO Ming-Guang, DU Ming-Run, ZHU Lu-Yao, LIU Bing-Bing

2013, 27(6): 793-801. doi: 10.11858/gywlxb.2013.06.001

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Abstract:
High pressure studies on one-dimensional (1D) carbon nanomaterials can provide deep insight into the new properties of carbon nanomaterials, which is also important for the fabrication of 1D superhard carbon nanomaterials. Here we present our recent research progress on high pressure studies of 1D carbon nanomaterials, including the results on structure stability, structure transitions and bonding change of fullerene nanotubes/nanorods, single-walled carbon nanotubes (SWNTs) and C60 filled SWNTs (C60@SWNTs) under pressure. The effect of nanosize and 1D nanoconfinement on the transformations of fullerenes under pressure is revealed. We also show how the structures of SWNTs transform under pressure, and further present the experimental evidence for the bonding formation of inter- and intra-tubes in compressed SWNTs.

Effects of the Vacancy Point-Defect on Electronic Structure and Optical Properties of Diamond under High Pressure

HE Lin, YIN Jun

2013, 27(6): 802-806. doi: 10.11858/gywlxb.2013.06.002

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Abstract:
By ultra-soft pseudo-potential approach of the plane wave based on the density-functional theory, the electronic structures and optical properties of diamond without and with vacancy point-defects were calculated at 255 GPa. The calculated results show that: at a shock pressure of 255 GPa, shock-induced vacancy point-defects in diamond crystal cause defective states within the band gap, and the optical absorption induced by the vacancy point-defects appears in the visible-light region of ~390-570 nm, and there is the transparency loss of diamond in that region. However, in the visible-light region of ~570-780 nm diamond remains transparent (its optical-absorption coefficient is still zero). Effects of shock-induced vacancy-defects on reflectivity and loss-function spectrums are similar: main-spectral peak move slightly toward short-wave region, and their intensity decreases to a small degree.

Precise Control Technique for Flatness of Flyer under Explosive Loading

JIN Ke, XI Feng, TAN Ye, LIU Xiao-Hai, DAI Cheng-Da, CAI Ling-Cang, WU Qiang

2013, 27(6): 807-812. doi: 10.11858/gywlxb.2013.06.003

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Abstract:
Based on the effective charge length model, the flyer flatness under explosive loading is improved by increasing the thickness of the attenuation plate gradually along radial orientation. The experimental results show that the difference of shock wave front arrival time is less than 80 ns within a range of 80 mm. The area, which is suitable for setting multiple samples in shock compression experiments, is enlarged by about four times than before. Measurements on shock Hugoniot data of tantalum and sound velocities of copper were performed by using the developed explosive loading technique. The obtained experimental data are all in excellent agreement with previously published results, showing that the new explosive loading technique can be used for multi-physics parameter measurements in shock compression experiments.

Material Point Method for Numerical Simulation of Underwater Explosion Blast Wave

CHEN Wei-Dong, YANG Wen-Miao, ZHANG Fan

2013, 27(6): 813-820. doi: 10.11858/gywlxb.2013.06.004

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Abstract:
Underwater explosive load calculation and numerical simulation are the key issues of the design of underwater conventional weapons and protection of ships and submarine. Numerical simulation of underwater explosions involves large deformation, the moving material interface and multi-media coupling. It has brought a lot of difficulties and challenges to the grid-based numerical algorithm. The material point method (MPM) is a meshfree method and takes the advantages of the both Euler and Lagrangian methods. Extension of the material point method to the numerical simulation of underwater explosion and the multi-medium coupling process was introduced. At last, spherical TNT underwater explosion in one-dimensional and TNT underwater explosion in two-dimensional were simulated. Blast wave produced by TNT exploding was computed. The spatial distribution and variation of the explosion flow field parameters were analyzed. The calculated results are in good agreement with the results of AUTODYN, empirical formula of Cole and SPH, and provide a important reference to engineering applications.

Comparison of Methods for High-Pressure Dynamic Yield Strength Measurement

YU Yu-Ying, TAN Hua, DAI Cheng-Da, PENG Jian-Xiang, LI Xue-Mei, HU Chang-Ming, TAN Ye

2013, 27(6): 821-827. doi: 10.11858/gywlxb.2013.06.005

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Abstract:
The four widely used methods to measure the high-pressure dynamic yield strength of solids, including Asay-Chhabildas (AC) method, lateral stress gauge (LSG) method, pressure-shear (PS) method, and X-ray diffraction (XRD) method, were analyzed in the present work. According to the difference of instant strain rate, the yield strengths defined by different methods hereinbefore are divided into two types: one is with high strain-rate, including the data from PS, XRD, as well as Y=Y=2c from AC method; the another is with zero strain-rate, including the data from LSG, and Y=Y=2H from AC method. The yield strengths of various aluminum and its alloys from publications were compared. Results show that the data from PS, XRD, and Y=Y=2c from AC method are approximately consistent, the data from LSG method, however, are obviously higher than the Y=Y=2H from AC method, and even higher than the data with high instant strain-rate. Further work is needed to determine the cause of the abnormal data from LSG method. Results also show that the Steinberg-Cochran-Guinan (SCG) model is strongly affected by the initial yield strength of materials, and a modified model is needed to describe the behavior of yield strength under high pressure or stress.

X-Ray Diffraction Investigation of Chalcopyrite under High Pressure and Temperature

FAN Da-Wei, WEI Shu-Yi, LIU Jing, XIE Hong-Sen

2013, 27(6): 828-832. doi: 10.11858/gywlxb.2013.06.006

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Abstract:
In situ angle dispersive X-ray diffraction measurements for a natural chalcopyrite were performed by using heating diamond anvil cell instrument with synchrotron radiation at BSRF up to 32.0 GPa and 628 K. The phase transition of chalcopyrite from chalcopyrite structure to rocksalt structure is around 6.0 GPa. A fit to the high temperature third-order Birch-Murnaghan equation of state yielded an isothermal bulk modulus K0＝109(3) GPa, a temperature derivative of the bulk modulus (dK/dT)p=-0.033(4) GPaK-1, and a thermal expansion coefficient 0=2.0(2)10-5 K-1 of rocksalt structure phase of chalcopyrite for the first time.

Numerical Studies on the Oblique Penetration Behavior of the Projectile with Cutting Mechanism into a Steel Target

GUO Liu-Wei, TAN Duo-Wang

2013, 27(6): 833-838. doi: 10.11858/gywlxb.2013.06.007

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Abstract:
The penetration behavior is very important for the semi-armor-piercing warhead. The oblique penetration behavior of the projectile with cutting mechanism was studied numerically by using the finite element code LS-DYNA. The penetration performance of the projectiles with and without cutting mechanism were compared respectively on the limit ricochet angle, the residual velocity after perforation, the dimension of the hole and the sliding distance of the projectile on the target before perforation. It shows that the numerical results agree well with the experimental ones. It reveals that the anti-ricochet effect of the cutting mechanism on the projectile is not so obvious but the dimension of the hole created by the projectile with cutting mechanism is much larger than that of the traditional projectile. The deflection and attack angle of the projectile with cutting mechanism change to different extent compared to the case of the traditional projectile. An optimized projectile with half cutting mechanism was proposed, and the simulated results showed that the anti-ricochet ability of this optimized projectile is better.

Calculation and Analysis for the Anti-Penetration Performance of Explosively Welded Steel/Aluminum Plates Target by the Penetration of Spherical Projectile

ZHOU Nan, WANG Jin-Xiang, XIE Jun, DONG Gang

2013, 27(6): 839-846. doi: 10.11858/gywlxb.2013.06.008

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Abstract:
A series of penetration-experiments were performed to investigate the anti-penetration performance of two and three layers explosively welded steel/aluminum and steel/aluminum/steel targets, the 14.5 mm slip chamber gun was used to launch the spherical steel projectile with diameter of 6 mm in the experiments. The failure modes of the layered targets were analyzed recur to the experimental results and on this basis a theoretical model was proposed to calculate the anti-penetration performance of the targets. The effects of different combinational style, thickness and intensity etc. on the anti-penetration performance of the targets were also analyzed qualitatively by the calculation model. The results show that: the damage mechanism of the steel front plate and aluminum middle plate is shearing and plugging, the steel rear plate is petalling damage and the aluminum rear plate is ductile prolonging; increasing intensity and thickness of the layered targets are beneficial for the anti-penetration performance; the anti-penetration performance of three-layer plates is better than that of the two-layer plates with the same total thickness; the results of theoretical calculation are well consistent with experimental results, indicating that the theoretical calculation model can predict the anti-penetration performance of layered targets effectively.

Numerical Simulation of Dynamic Fracture Toughness Test Using Three-Point Bending Specimen in SHPB

PAN Jian-Hua, CHEN Xue-Dong

2013, 27(6): 856-862. doi: 10.11858/gywlxb.2013.06.010

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Abstract:
This paper examines 3D and 2D numerical simulations of dynamic fracture toughness test using TPB specimen in SHPB by using commercial code ABAQUS 6.8 and 3D fracture mechanics code ZENCRACK 7.7. The finite element model includes the whole experimental device (the projectile, the input bar, the specimen and the supporting device). Three cases of specimens with different initial crack length impacted by projectiles were simulated, and dynamic stress intensity factor impulse response curves were obtained. The dynamic initial fracture times, tf, were extracted from RKR local stress fracture criterion. The material dynamic fracture toughness are successfully obtained from numerical simulations. The simulated results from 2D and 3D FEM are compared with benchmark tests, finding that 3D finite element results are better than 2D results.

Meso-Scale Numerical Simulation of the Shock Compression of Particle Metal Materials

QIAO Liang, ZHANG Xian-Feng, HE Yong, SHI An-Shun, ZHANG Jiang

2013, 27(6): 863-871. doi: 10.11858/gywlxb.2013.06.011

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Abstract:
Meso-scale characteristics of particle metal materials (PMM) play an important role in determining its macro-scale mechanical property. In order to investigate relationship between meso-scale characters (particle size, distribution, morphology, porosity) and macro-scale mechanical property, a FEM meso-scale model which can follow the distribution of real structure was built with reasonable simplification. By exploiting AUTODYN FEM software, shock compression process of PMM was simulated and Hugoniot parameters of typical PMM were extracted. Based on the simulated results, conclusion was made on how the meso-scale characteristics (e.g. theoretical mass density, particle size) make impact on the macro-scale shock compression mechanical property. Deformation morphologies and temperature rise during shock compression were also acquired by simulations. It is shown that the simulated result shows a good agreement with the experiment and the meso-scale characteristics of PMM play an important role on its macro-scale property.

Simulations of Seismic Waves Stimulated by Aluminized Explosive

ZENG Yi-Xin, BAI Chun-Hua, CHEN Jian, WANG Zhong-Qi

2013, 27(6): 872-876. doi: 10.11858/gywlxb.2013.06.012

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Abstract:
In order to study the propagation of seismic waves stimulated by aluminized explosives, the commercial software-AutoDyn was used, in combination with Miller energy release model, to simulate the explosion in the sand. The results of simulation agreed well with the experiment: 0.7 kg aluminized explosive aluminized explosive was buried with a depth of 1 m in the sand, and its root mean square (RMS) amplitude of surface seismic waves was 1.23 times more than TNT; while the seismic energy density of waves passed down diminished exponentially with the depth, and seismic energy of Aluminized explosive passed down was 1.34 times more than TNT.

Theoretical Considerations on the Temperature Rise of Shaped Charge Particle Jet

中北大学化工与环境学院, 山西太原, 中国科技大学近代力学系, 安徽合肥

2013, 27(6): 877-883. doi: 10.11858/gywlxb.2013.06.013

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Abstract:
To estimate theoretically the temperature rise of shaped charge particle jet, the temperature rise was calculated based on the equation of state of the porous material determined. The temperature rise includes heating due to the shock wave transferred into the porous liner by the explosive detonation wave and due to the plastic work performed during porous liner and shaped charge particle jet elongation. The temperature rises of the porous copper shaped charge particle jet and the solid copper shaped charge jet were calculated by the MATLAB software. The calculated results show that: the temperature rise of the porous copper shaped charge particles jet was significantly higher than that of the solid copper shaped charge jet, because of the contribution that the shock wave transferred to the porous liner by the explosive detonation wave.

Experimental Study on Dynamic Behavior of the Collision Region of Lead Tube Driven by Cylinderical Implosion

ZHANG Chong-Yu, HU Hai-Bo, LI Qing-Zhong

2013, 27(6): 884-888. doi: 10.11858/gywlxb.2013.06.014

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Abstract:
Dynamic behaviors of the collision region of lead tube driven by cylinderical implosion were experimentally investigated by high-speed frame photography and pulsed X-ray radiography. Experimental results showed that a leading jet-like spiking happened in the collision region, and the spiking demonstrated obvious instability tendency. Due to the existence of high pressure in the collision region, lead may be melted and transformed into liquid without shear strength. Shock-melting may be the main reason for the occurrence of the jet-like spiking in the collision region of lead tube. Additionally, three leading spikings observed in the collision region is reported for the first time. Preliminary analysis attributed the above phenomenon to the reflection and superposition of waves caused by head-on collision of two detonation waves, and the detailed reason should be further analyzed in future work.

Simulation Analysis on Structure Safety of Refuge Chamber Door under Explosion Load

LUO Xing-Na, HUANG Ping, QIAN Xin-Ming

2013, 27(6): 889-896. doi: 10.11858/gywlxb.2013.06.015

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Abstract:
The door of coal mine mobile refuge chamber should keep strong structure during its life cycle. A basic structure of the door was designed. And finite element models of the door were established for numerical simulation, with thickness 10, 20, and 25 mm, respectively. Finite element software ANSYS/LS-DYNA was used in the numerical simulation. Deformation of the door under a triangle explosion shock wave with maximum value for 0.6 MPa and 300 ms duration was calculated. The maximum stress value appears in the connection position between the door plank and reinforced stiffeners. The maximum displacement value appears in the middle of the door plank. Stiffeners have significant effect on the maximum displacement. The maximum displacement of improved chamber door is reduced to 5.25 mm, having a decrease of 19.22 mm. According to the simulation analysis, the door with 20 mm thickness could fulfill the requirements of structure safety.

Asay-F-Window Applied to Diagnostic of Micro-Spall Phenomena

CHEN Yong-Tao, REN Guo-Wu, TANG Tie-Gang, LI Qing-Zhong, WANG De-Tian, HU Hai-Bo

2013, 27(6): 897-900. doi: 10.11858/gywlxb.2013.06.016

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Abstract:
Quantitative data on micro-spall fragments production from metals melted on shock or release are sparse because of diagnostic limitations. In this study, a new diagnostic technology Asay-F-Window was designed, and the mass-velocity distribution of micro-spall fragments was presented. By comparing the measured results of Asay-F-Window with those of piezoelectric pins, the reliability of Asay-F-Window technique was evaluated.

Measurement of Solid Armature's in Bore Velocity Using B-Dot Probes in Series Enhanced Railgun

CHENG Cheng, GUAN Yong-Chao, HE Yong, GAO Gui-Shan, LI Ye-Xun, QIU Xu, SONG Sheng-Yi

2013, 27(6): 901-907. doi: 10.11858/gywlxb.2013.06.017

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Abstract:
The solid armatures displacement and velocity can be obtained by arranging B-dot probe arrays along the barrel of a series enhanced railgun. The moment of armature arrival can be determined by an evident change in the differential signals of B-dot probes while armature passing by. However, it is difficult or even impossible to pick up the arrival moment directly because of not only armature movement but also current variety, especially for the series enhanced railgun with currents in outer rails and connecting conductors. To eliminate the influence of current variety, the ratio function is introduced, which is the ratio of the differential signal integral to the current. The ratio function of armature B-dot probe will reach a maximum when the armature arrives, while the one of rail B-dot probe will reach the median. Three shots with same initial conditions, which adopted armature probe, rail probe and VISAR respectively, were carried on a series enhanced railgun. The well agreement with each other about displacement and velocity waveforms indicated that method and measurement were valid. The accuracy of B-dot method is mainly affected by probe size and position, railgun current distribution and electromagnetic noise.

Synthesis of the Single Crystal of MgSiO3 Perovskite in Capsules with Different Lengths

XU Jun-Shan, WU Xiao-Ping

2013, 27(6): 908-914. doi: 10.11858/gywlxb.2013.06.018

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Abstract:
MgSiO3 perovskite is the most abundant material in the Earths lower mantle. It is very difficult to obtain single crystal of MgSiO3 perovskite due to its high pressure stability over 22 GPa. Thus synthesis of MgSiO3 perovskite, especially the large grain size single crystal, is extremely important to investigate the properties of lower mantle. In this study, the details of synthesizing the single crystal of MgSiO3 perovskite with large grain size were presented. Our synthesis experiments were conducted at a condition of 25 GPa and 1 500 ℃ using a 5 000 t Kawai-type multi-anvil apparatus. The results using different lengths of Pt capsule showed the large grain size perovskite crystal can also be obtained even at the large temperature gradient area in longer Pt capsule, which is different from previous experimental results. It is suggested that a large temperature gradient in the sample capsule can increase the nucleation density, however, it can also boost the crystal growth of perovskite and thus crystal can grow at a fast speed. Furthermore, the perovskite growth mechanism was investigated through analysis of twin crystal, which is important to understand the characteristics of the crystal growth of MgSiO3 perovskite at high pressures.

Experimental Investigation on the Ballistic Performance of 45 Steel Metal Plates Subjected to Impact by Hemispherical-Nosed Projectiles

DENG Yun-Fei, ZHANG Wei, CAO Zong-Sheng

2013, 27(6): 915-920. doi: 10.11858/gywlxb.2013.06.019

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Abstract:
A series of impact tests were conducted to investigate the ballistic performances of single, double- and three-layered 45 steel plates subjected to impact by hemispherical-nosed projectiles which were made from 38CrSi and diameter was 12.7 mm, the impact velocities ranged from 240 m/s to 600 m/s. The multi-layered plates arranged in various combinations of the same total thicknesses were normally impacted with the help of a gas gun. The initial and residual velocities of the projectiles were measured, and also the ballistic limit velocity for each configuration target was obtained and compared based on the investigation of the effect of the number of layers on the ballistic resistance. The results indicated that the ballistic limit velocity of multi-layered plate was higher than that of monolithic plate. The dominant failure model of monolithic plate was shearing, but the dominant failure models of multi-layered plate were global dishing and local bulging. Moreover, the failure models of plates of multi-layered plates were in relation to their order.

Improved Quasi- Function Pulse Pressure Dynamic Calibration of High-Pressure Transducer

ZHANG Yu, ZU Jing, ZHANG Hong-Yan

2013, 27(6): 921-927. doi: 10.11858/gywlxb.2013.06.020

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Abstract:
Based on the analysis of shortcomings existed in quasi- function calibration method, a dynamic calibration method was proposed. In this method, a pressure sensor was under high static pressure in advance, and then a bullet was used to impact Hopkinson bar for generating a quasi- function signal with small amplitude, which excited the sensor being calibrated, and finally a frequency response characteristics of the sensor was obtained. The principle of quasi- function dynamic calibration method was introduced. The relation of pulse width of quasi- function signal, calibrated frequency range, and calibration precision was analyzed. The dynamic calibration system was established. This calibration method realized dynamic calibration of high pressure sensor under actual working pressure, and realized the tracing from zero frequency to a certain frequency needed. On the current technical level, the maximum static pressure is 800 MPa, the pulse width of the quasi- function signal is within 7 s to 10 s, the calibrated frequency range is from 0 to 20 kHz, and calibration error of amplitude-frequency characteristics is 5%.

Study on the Effects of Composite Armor with Corrugated Sandwich against the Shaped Charge Jet Penetration

ZHANG Zhong-Wen, HUANG Zheng-Xiang, ZU Xu-Dong, JIA Xin

2013, 27(6): 928-935. doi: 10.11858/gywlxb.2013.06.021

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Abstract:
The anti-penetration property of the corrugated sandwich composite armor with the corrugation angle of 45 in different penetration angles was studied. The performance of the armors filled with rubber and without rubber was studied, based on the energy loss, DOP and quality protection factor considerations. The energy absorption characteristics of the armor filled with rubber was analyzed. The reliability of the simulation results was validated by 56 mm stander shaped charge penetrating the steel at 0 dip angle and the composite armor at 60 dip angle. The results showed that the protection capability of the corrugated sandwich composite armor with corrugation angle of 45 was effective. Its beneficial to fill the corrugation gaps with rubber. This kind of composite armor has excellent protection capability and can be used as a new kind of light armor.

Effects of Dynamic High-Pressure Microfluidization Treatment on Vitamin C, the Total Polyphenol Content and the Antioxidant Activity of Pineapple Juice

LI Ti, LI Qian, XU Jin-Long, LIU Cheng-Mei, WANG Zhao-Yun

2013, 27(6): 936-941. doi: 10.11858/gywlxb.2013.06.022

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Abstract:
The effect of dynamic high-pressure microfluidization (DHPM) treatment on vitamin C, the total polyphenol content and the antioxidant activity of fresh pineapple juice was studied. Results indicated that the vitamin C content decreased after DHPM treatment. Under the pressure of 30 MPa, the loss of vitamin C was most. The total polyphenol content in fresh pineapple juice showed different degree of reduction after DHPM treatment. Under the pressure of 60 MPa, the total polyphenol content was the lowest, which was about 383.19 mg/L. The antioxidant capacity of pineapple juice decreased after the different DHPM pressure treatment compared to the untreated one by phosphomolybdenum method and ferric reducing/antioxidant power assay.

Effect of the Pressure on Iron Magnetic Resonance and Faraday Rotation in Ce:YIG

YANG Dan, ZHANG Guo-Ying, HU Feng, CHEN Hui, HUANG Yi-Jia

2013, 27(6): 942-945. doi: 10.11858/gywlxb.2013.06.023

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Abstract:
The variations of the damping coefficient and molecule field with the pressure are investigated, and the quantitative forms are given in Ce:YIG crystal. The variations of the line width of iron magnetic resonance and the magneto-optic Faraday rotations with the pressure are presented. The calculated results are agreement with the measured values in the pressure range of 1.33-13.30 Pa. The investigation indicates the dependence of the magnetic and magneto-optic properties of Ce:YIG crystal on the pressure. It is important that the pressure should be controlled properly in the preparation of materials.

2013 Vol. 27, No. 6

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