高压物理学报

Numerical Simulation of Craters Produced by Projectile Hypervelocity Impact on Aluminum Targets

ZHANG Wei, MA Wen-Lai, MA Zhi-Tao, PANG Bao-Jun

2006, 20(1): 1-5 . doi: 10.11858/gywlxb.2006.01.001

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Abstract:
All spacecrafts in low orbit are subject to hypervelocity impacts by meteoroids and space debris. These impacts can damage spacecraft flight-critical systems, which can in turn lead to catastrophic failure of the spacecraft. In order to ensure the astronauts safety and spacecraft normal operation, the design of meteoroids and space debris protection configuration become an important problem of spacecraft design. The numerical simulation of craters produced by projectile hypervelocity impact on aluminum targets at normal and oblique angles have been carried out using the AUTODYN hydro-codes in this paper. The results using two and three-dimensional simulations are given. The effect of projectile density, shapes, target thickness, projectile diameter, impact velocity and angles etc. on crater has been investigated. The simulation results are compared with experimental results, and the simulated crater shapes and characteristic sizes are consistent very well with experimental results. The validation of numerical simulation method has been verified.

Fluorescence of Rhodamine 101 under High Pressures

ZHAO Zhi, DING Ze-Jun, WANG Zhong-Ping, TANG Xu-Dong, ZHANG Zeng-Ming

2006, 20(1): 6-10 . doi: 10.11858/gywlxb.2006.01.002

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Abstract:
The fluorescence spectra of both Rhodamine 101 powder and solution (mixture of methanol, ethanol and water as solvent) have been measured under high pressures. It has been found that the emission character of Rhodamine 101 powder is quite different from that in solvent under high pressures. For Rhodamine 101 powder, the fluorescence intensity drops quickly with the increase of pressure and disappears almost at 8 GPa, while the emission peaks move redward dramatically (about 100 nm within 8 GPa). For Rhodamine 101 solution, the fluorescence intensity decreases slowly with the increase of pressure; the emission intensity at 13 GPa is about 10% of that at the ambient pressure. Moreover, the emission peak moves redward comparatively slowly (about 50 nm within 13 GPa). The change of molecular structure and special solvent effect are, respectively, the primary factors that influence the emission character of Rhodamine 101 powder and solution under high pressures.

Synchrotron Radiation Diffraction of Enstatite under High Temperature and High Pressure

MA Yan-Mei, ZHOU Qiang, YANG Kai-Feng, LI Xue-Fei, SHEN Long-Hai, CUI Qi-Liang, LIU Jing, ZOU Guang-Tian

2006, 20(1): 11-14 . doi: 10.11858/gywlxb.2006.01.003

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Abstract:
In-situ energy dispersive X-ray diffraction measurements of enstatite have been studied by using diamond anvil cell (DAC) with synchrotron radiation and laser heating in the range of 0~23 GPa and 293~2 000 K. We have found that enstatite transform to wadsleyite phase at 15.3 GPa and 1 600 K. At temperatures up to 2 000 K and pressure up to 23 GPa we have observed mixed phase of ilmenite and perovskite structure. The experiment further demonstrates that the density and seismic-wave velocity jumps are attributed to the phase transition of olivine and enstatite minerals.

Ab initio Calculation of the Effective Inter-Atomic Pair Potential in Liquid Helium

TIAN Chun-Ling, LIU Fu-Sheng, CAI Ling-Cang, JING Fu-Qian

2006, 20(1): 15-19 . doi: 10.11858/gywlxb.2006.01.004

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Abstract:
Ab initio Hartree-Fock self-consistent-field (SCF) technique and the atomic cluster method have been applied to study the effective inter-atomic pair potential in liquid helium. The atomic cluster (He)9 with BCC geometry (only taking the first neighbors into account) is used to stimulate the average atomic configuration in liquid states. A theoretical effective potential is derived based on the new average coordination model and many-body series expansion approach. The obtained pair potential is very close to the experimental calibrated Exp-6 potential, by which both the isotherm and Hugoniot of liquid helium are well described.

A New Carbon Nitride Phase Synthesized by Shock Compression

LIU Jian-Jun, SEKINE T, KOBAYASHI T

2006, 20(1): 20-24 . doi: 10.11858/gywlxb.2006.01.005

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Abstract:
To synthesize a carbon nitride with high density existing by theoretical prediction, a series of shock recovery experiments up to 50 GPa were carried out on two nitrogen-rich materials of a C-N-O amorphous precursor and dicyandiamide. The powder X-ray diffractions (XRD) of recovered samples show that the carbon nitride composite phases are formed consisting of -C3N4 and a new crystalline phase. The new phase is indexed as a monoclinic cell with a=0.981 nm, b=0.723 nm, c=0.561 nm, =95.2, and Vcell=0.396 6 nm3. We considered that this new phase is formed to survive as metastable species by extremely high quenching rate (109 K/s) after transient shock-induced reaction of these organic precursors and so shock compression may provide a novel synthesis route for various carbon nitride phases from appropriate rich-nitrogen organic materials.

Research on the Raman Spectra of Gypsum at Pressure of 100~800 MPa and Room Temperature

YANG Yu-Ping, ZHENG Hai-Fei

2006, 20(1): 25-28 . doi: 10.11858/gywlxb.2006.01.006

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Abstract:
This paper measures the Raman peak displacements of the four vibration modes of SO bonding and the hydroxyl-stretching vibration modes in the gypsum at high pressures using diamond anvil cell. The experimental results show that at the temperature of 25 ℃ and the pressure of 100～800 MPa the Raman peak positions of the SO bonding in the gysum shift to high wave numbers with the increase of the system pressure, while the Raman peak positions of hydroxyl-stretching vibrations shift to low wave numbers with the increase of the system pressure. The relations between the Raman peak positions and system pressure were obtained, and the two d/dp values of hydroxyl-stretching vibrations show a great difference because of different intensity of the hydrogen bonding.

Discussion on the Mechanism of cBN Synthesized by Benzene Thermal Method Using (C2H5)2OBF3 and Li3N as Reactants

WANG Shao-Bo, XU Xiao-Wei, FAN Hui-Li, ZHENG Yan-Jun, LI Yu-Ping

2006, 20(1): 29-33 . doi: 10.11858/gywlxb.2006.01.007

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Abstract:
BN is synthesized by benzene thermal method using (C2H5)2OBF3 and Li3N as reactants and its phase transition mechanism is studied. Not only hBN and cBN are found in the products testified by XRD and FTIR, but also oBN, atmosphere form Li3BN2(O) and high pressure form Li3BN2(T) are discovered. The differences of cBN catalytic mechanism between high pressure and high temperature method and benzene thermal synthesis method are analyzed. Furthermore, the catalytic mechanism of Li3BN2 to synthesize BN using Li3N and (C2H5)2OBF3 as reactants is discussed. At the same time, it stands out the atmosphere form Li3BN2(O) and the high pressure form Li3BN2(T) can catalyze the synthesis of cBN and oBN, respectively.

Spall Fracture Properties of AF1410 Steel

GUI Yu-Lin, LIU Cang-Li, WANG Yan-Ping, SUN Cheng-Wei

2006, 20(1): 34-38 . doi: 10.11858/gywlxb.2006.01.008

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Abstract:
The spall properties of AF1410 steel are studied with the loading by gas gun. The Hugoniot relationship, plastic strain rate, spall strength, spall thickness and other dynamic parameters are obtained from experimental measurement. By the fracture analysis and metallographic analysis, the spall fracture mechanism at different strain rate is discussed.

2D Numerical Simulation of Explosive Damage Effect on Obstacles in Water

HAO Li, NING Jian-Guo, WANG Cheng

2006, 20(1): 39-44 . doi: 10.11858/gywlxb.2006.01.009

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Abstract:
The physical and computational models of explosive damage effect of obstacles in water are proposed. The conservation equations, the dynamic elastic-plastic constitutive relation and damaging criterion of concrete are established, together with the yielding criterion subjected to large strains, high strain rates and high pressures. Meanwhile, based on the multi-material Eulerian algorithm, the NM-MMIC code, which is a general 2D multi-material elastic-plastic hydrodynamics code with C++ language, is applied to simulate the damaging effects of obstacles in water by explosion with different charges and at different positions. The whole process of underwater explosion are visualized by VISC2D code. The pressure variation of the side of the obstacle facing to the explosive are demonstrated quantitatively. The optimum damage charge is obtained. The damaging degree, and the damage laws of the obstacle in water are evaluated. These results are valuable in designing and estimating ammunitions against obstacles in water.

Numerical Simulation of Temperature Effects on Warhead Explosion Products

LUO Ai-Min, ZHANG Qi

2006, 20(1): 45-50 . doi: 10.11858/gywlxb.2006.01.010

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Abstract:
Relation between mass density of explosive detonation products and time is studied under three kinds of confinement conditions, i. e., no confinement, weak confinement, and rigid confinement by coupling of BKW code, JWL code and LS-DYNA program, respectively. Associated with HOM equation of state, explosion products temperature decaying with time is inferred, and theoretical method is proposed to calculate explosion products temperature of warhead. Results imply that temperature and its decaying rate in explosion products region are non-uniform. Confinement condition plays an important role in controlling of explosion products mass density and its temperature. Rigid confinement could postpone the decaying of the explosion products density and temperature, but the decaying time does not scale up in spite of the doubling of the shell thickness.

An Isothermal Three-Parameter Equation of State Applied to Alkali Halide Crystals under High Pressures

YAN Zu-Tong

2006, 20(1): 51-55 . doi: 10.11858/gywlxb.2006.01.011

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Abstract:
From the definition of isothermal bulk modulus and an assumption of its relationship with the pressure, an isothermal three-parameter equation of state has been proposed, which is found to be applicable at high pressure. The proposed equation of state has been used to compute the pressure-volume behavior of NaCl crystal in the pressure range 0~30 GPa and CsCl crystal in the pressure range 0~40 GPa. The isothermal bulk modulus in the pressure range 0~30 GPa of NaCl crystal were also calculated. The results are in very good agreement with the experimental data. The pressure dependence of the isothermal bulk modulus BT and its first- and second-order pressure derivative are discussed, and the bulk modulus increases continuously with the increasing pressure and has a finite value as p.

Study of Optical Properties and Electronic Structure of V in ZnS by First Principles

HE Kai-Hua, YU Fei, JI Guang-Fu, YAN Qi-Li, ZHENG Shu-Kui

2006, 20(1): 56-60 . doi: 10.11858/gywlxb.2006.01.012

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Abstract:
The optical properties and electrical structure of V in ZnS supercell have been computed by means of plane wave pseudo-potential method (PWP) with generalized gradient approximation (GGA). The calculated optical property is in consist with the values calculated by the theory of crystal field and with the experiment results. By importing impurity, the energy level has a shift about -2.5 eV. The Mulliken charge of V is 0.28, which is smaller than every kind of Zn, and the covalency of bond SV is strongest than other bonds, and the length is the shortest.

Numerical Calculation of Ferroelectric Power Supply Initiating Metal Bridge Foil

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

2006, 20(1): 61-66 . doi: 10.11858/gywlxb.2006.01.013

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Abstract:
To investigate the effect of ferroelectric power supply initiating metal bridge foil, the electrical responses of the shock-loaded PZT95/5 ferroelectric with copper bridge foil load were numerically calculated. The non-linear resistance model was used for the metal bridge foil. The voltage, current, and resistance of metal bridge foil under different number of ferroelectric blocks arranged in parallel were calculated. By the results of calculated voltages and resistances of copper bridge foil, the number of parallel ferroelectric blocks to make copper bridge exploding was obtained. The calculation and results provide a theoretical basis to design the ferroelectric power supply initiating metal bridge foil.

Dynamic Cylindrical Cavity Expansion Model and Its Application to Penetration Problems

Zhou Hui, Wen He-Ming

2006, 20(1): 67-78 . doi: 10.11858/gywlxb.2006.01.014

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Abstract:
Dynamic cylindrical cavity expansion model and its application to penetration problems were studied. Both incompressible and compressible bilinear strain-hardening material models were considered. First, solutions for dynamic cylindrical cavity expansion (DCCE) are obtained in terms of the velocity of plastic wave front, radial stress distribution and stress on the cavity surface. The influence of material properties such as compressibility, elastic-plastic constitutive equations and plastic modulus is discussed. Based on the DCCE models, penetration equations are then constructed. Comparison with experimental penetration data shows reasonable agreement between theory and experiment. It also shows that material properties such as plastic modulus have considerable effects on the dynamics cavity expansion and its resistance to penetration.

Image Excursion Analysis of Two Rotating Mirror High-Speed Cameras Used Simultaneously

LIU Ning-Wen, SANG Yong-Sheng, XIAO Zheng-Fei, CHANG Li-Hua, SHANG Chang-Shui

2006, 20(1): 79-82 . doi: 10.11858/gywlxb.2006.01.015

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Abstract:
Reasons of imaging excursion of two rotating mirror high speed cameras used simultaneously are discussed, and the influence to images are analysed according to the theories and experiments, such as the signal drift of the magnetoelectric sensor and improperly operating etc. Finally some measurement are taken to reduce the image excursion.

Effect of Ultra-High Pressure Processing (UHPP) on the Microstructure of Bacillus subtilis

ZENG Qing-Mei, XIE Hui-Ming, PAN Jian, YANG Yi, XU Hui-Qun, HUANG Xun-Duan, ZHAO Yang-Nan

2006, 20(1): 83-87 . doi: 10.11858/gywlxb.2006.01.016

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Abstract:
The effect of ultra-high pressure processing on the microstructure of Bacillus subtilis AS 1.140 was investigated, and the inactivation mechanism of its vegetative form and spore was studied. The change of B. subtilis microstructures were analyzed and compared in terms of the oberation with a Transmission Electron Microscope (TEM) after UHPP (500 MPa, 60 ℃, 20 min). Results showed that the vegetative cell wall of B.subtilis was shrinked, breached and leaked out cytoplasm, the layer structure of cytoplasm disappeared, and a large electron transmission area appeared in the cell after compression. The outer coat of its spores was also breached, the layer structure of spores' inclusion disordered, the inclusion leaked out from the cell, and a partial electron transmission area appeared after compression.

Experimental Study of the Compressible Behavior of Low-Density Polyurethane Foam

LIN Yu-Liang, LU Fang-Yun, WANG Xiao-Yan, ZHAO Xi-Jin

2006, 20(1): 88-92 . doi: 10.11858/gywlxb.2006.01.017

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Abstract:
The compressive stress-strain behaviors of polyurethane foams in four different mass densities have been tested by SHPB at strain rates of 1103～5103 s-1. Experimental results show that the compressive behavior of the polyurethane foam is sensitive to the strain rates between quasi-static experiments and SHPB experiments. However, the behavior is not sensitive to the strain-rate under condition of dynamic compression. A experiential constitutive relation, which considers density effect of the foams on materials features at high strain-rates, has been proposed based on Sherwood model. The relation is well agreed to the experimental data.

Application of Interparticle Contact Algorithm Based on Riemann Solution in SPH

XU Zhi-Hong, TANG Wen-Hui, ZHANG Ruo-Qi

2006, 20(1): 93-96 . doi: 10.11858/gywlxb.2006.01.018

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Abstract:
Smooth particle hydrodynamics (SPH) is a new effective numerical method for modeling problems involving large deformation. However when the SPH method is used to simulate shock waves come across contact interface, tensile instability occurs at the contact interface. In this paper we use contact algorithm which describes contact interaction between SPH particles by means of Riemann solution to simulate the propagation of wave in shock tube and projectile impact problems, and compare the numerical results with the analytical solutions. From the compared results, we can conclude that the modified SPH method do well in removing instabilities and improving accuracy of calculation. And due to the introduce of Riemann solution, there is no need to use artificial viscosity and heat flux, which simplifies the program code.

Principle Experiments Research of Technique for Quasi-Isentropic Magnetically Driven Flyer Plates

ZHANG Zhao-Hui, LIU Cang-Li, YANG Li-Bing, GU Yuan-Chao, ZOU Jie, HUANG Xian-Bin, OUYANG Kai, LI Jun, LIU Qiao, DENG Xiang-Yang

2006, 20(1): 97-101 . doi: 10.11858/gywlxb.2006.01.019

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Abstract:
Experiments were performed to investigate the quasi-isentropic magnetically driven flyer plates with several sizes on FP-1, and their velocity histories were recorded by VISAR. When the maximum current was 3 MA, the maximum velocity of flyer plate was 797.3 m/s. Through this work, we get the principle technique for quasi-isentropic load. This will be helpful to further development of the magnetically driven quasi-isentropic load technique, launching flyer plates technique and the study of equation of state.

Behaviors of Shock Initiation and after-Initiation for Heterogeneous Explosives

LI Yin-Cheng

2006, 20(1): 102-108 . doi: 10.11858/gywlxb.2006.01.020

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Abstract:
Campbell's and other authors' experimental studies of behaviors of initiation and after-initiation for heterogeneous explosives were introduced and analyzed, but initiation conditions were not dealt with. When an intense shock wave enters a heterogeneous explosive charge, detonation is initiated by the shock wave instantaneously (i. e. not to undergo induction time) and directly (i. e., not to pass through other processes, such as deflagration). Then a building up detonation wave propagates throughout the heterogeneous explosive charge until it develops into a normal detonation. This whole process is called the buildup of detonation with the new definition in this paper. The so-called reactive shock wave is the building up detonation wave in early stage. Buildup of detonation (in terms of new definition) is a characteristic for all secondary explosives. Incomplete reaction and running to complete reaction of explosives are the chemical mechanism of buildup of detonation.

Numerical Simulation of Fragment Impacting on Charge with Aluminum Shell

CHEN Hai-Li, JIANG Jian-Wei, MEN Jian-Bing

2006, 20(1): 109-112 . doi: 10.11858/gywlxb.2006.01.021

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Abstract:
Numerical simulation for the initiation or ignition of explosive with aluminum shell was carried out following the Lee-Tarver initiation model of the Autodyn-2D code when it was impacted respectively by sphere or column form fragment. The influence on charge detonation of the shape and velocity of fragments, and the thickness of aluminum was analyzed. By means of the up-down method, the critical detonation velocity of Octol was obtained.

2006 Vol. 20, No. 1

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