Table of Content

30 September 1991, Volume 12 Issue 3

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Paper

General Equations of Kinematics & Dynamics in Gear Trains and the Simulation of Transient Processes During Shifting

Zhao Zhiyong、 Li Lianzhou、 Chen Ruiting

1991, 12(3):  1-7.  doi:10.3969/j.issn.1000-1093.1991.03.001

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The paper takes together systems of fixed axis gears and those made up of planetary gear sets for study and analysis，arriving at a method which, starting from the structural scheme of the gear train, can establish the general equations in kinematics and dynamics for any arbitrary situation, through gradual recursion and continuous manipulation with matrices. In this way,the equations can easily be set up and solved with the computer, as required by the transient conditions at any instant. The method given is quite novel and both the method and equations are general in character, suitable for the analysis and calculation in kinematics and dynamics of gear trains consisting either of fixed axis gears or of three- component planetary gears in both the steady and unsteady states. Following the given mathematical model and methods, it is then easy to establish, computer programs to simulate transient processes during shifting according to actual situations.

On the Motion of Projectile Axis Caused by Gravity

Rui Xiaoting

1991, 12(3):  8-12.  doi:10.3969/j.issn.1000-1093.1991.03.002

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This paper derives, the yaw of repose and the Mayevsky equation from the special solution of equation of the angle of yaw and dynamic balance respectively. It shows that there exists no essential difference between them, and that they are all caused by gravity. In their physical nature they reveal the conservation of moment of momentum of a projectile relative to the moving coordinate system-a product of dynamic balance.

A Base Bleed Gasdjnamic Model

Wang Nanyan

1991, 12(3):  13-19.  doi:10.3969/j.issn.1000-1093.1991.03.003

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A two-phase base bleed gasdynamic model is presented. In the model the exit area ratio，solid particle mass ratio，fuel enthalpy of combustion, jet gas molecular weight, chamber stagnation temperature, flight Mach number etc. have been considered. A complete calculation method has also been established with a computor program by which the predicted results show general agreement with the available experimental curves.

A Simple Analytical Method for Calculating Two-Dimensional Base Pressure at Supersonic Speed

Wu Zhenyu

1991, 12(3):  20-25.  doi:10.3969/j.issn.1000-1093.1991.03.004

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A simple analytical method for calculating two-dimensional base pressure at supersonic speed is presented, based on the use of the law of conservation of mass and the law of conservation of energy. The theoretical predictions are compared with experimental results. On the whole the agreement is satisfactory.

Numerical Solution & Dispersion Analysis for Airbonie Rocket Trajectory

Liu changli

1991, 12(3):  26-31.  doi:10.3969/j.issn.1000-1093.1991.03.005

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Numerical solution and dispersion analysis for airborne rocket trajectory are studied. With the airborne rocket taken as a rigid body, the whole set of equations of motion for the six degrees of freedom are presented, involving factors of thrust malalignment，dynamic imbalance and initial disturbance. In order to overcome difficulties arising from the contradictory requirements on accuracy and speed of computation for trajectory data, the paper proposes a scheme that combines functional approximation. Runge-Kutta and Hamming methods. Monte-Carlo statistical simulation is then used to calculate and analyse the dispersion of airborne rocket under the action of random perturbations. Finally，numerical examples of theoretical trajectory and rocket dispersion are given for a certain airborne rocket. Results from computer simulation turn out to be quite satisfactory.

Plasma Polymerization Technique for the Formation of Barrier - Layers upon Propellants

Li Guangtao、 Li Rongzhi、 Zhu Hesun

1991, 12(3):  32-37.  doi:10.3969/j.issn.1000-1093.1991.03.006

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The development of a new composite barrier layer on the surface of double base solid propellants is presented, utilizing the plasma polymerization technique. The barrier layer is compatible with the grain. It sticks fast with both the double base solid propellant and the inhibitor coating of the propellant and will not crack upon temperature changes. Besides, the anti plasticizer migration (including NG) property is most satisfactory. The technique solves the problem of migration as well as failure at the inhibitor一propellant interface that usually arise in solid propellant charges, thus introducing a new technology in inhibitor coating of propellants

Reaction of Solid Propellants under Shock Loading

Bai Chunhua、 Ding Jing

1991, 12(3):  38-47.  doi:10.3969/j.issn.1000-1093.1991.03.007

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In this paper, reactions of double-base (DB)，high, energy modified double-base (HMDB) and two composite propellants are studied and shown to be similar to that of heterogeneous high explosives. In these propellants，the explosive components react independently and the diffusion of products can be ignored.The reactions of the two composite propellants， whose binders are thiokol and hydroxy terminated polybutadine (HTPB) respectively, differ greatly from those of DB and HMDB propellants. The reactions of these propellants proceed in three stages. In the first stage，the binder and ammonium perchlorate (AP) react independently and the products of AP also react with that of the binder and aluminum powder (Al). At the end of this first stage，under the high shock pressure the binder bacomes a viscous liquid，covers the AP crystal surface and hinders the reaction of AP. For this reason，there is a short intervening reactionless stage. After this the decompositions of the binder and AP restart and the reaction of the products of AP with those of the binder and Al proceed again.

Fire Control Process for the Off-Boresight Launching of Air-to-Air Missiles

Gao Xiaoguang、 Zhang Zilie

1991, 12(3):  48-53.  doi:10.3969/j.issn.1000-1093.1991.03.008

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This paper gives a study of the fire control process for the off-boresight launching of air-to-air missiles. The missiles capacity of cff-boresight uiuncliing and of performing all-round attacks is analysed. The feasibility of the fire control process is seen through some simulations of aerial combats.

Experimental Techniques and Analysis

Master Curves for Viscoelastic Properties of HTPB Composite Propellants

Zhao Bohua、 Xin Zhenhe

1991, 12(3):  54-59.  doi:10.3969/j.issn.1000-1093.1991.03.009

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In this paper master curves and their mathematical for mulations for the complex modulus，storage modulus，loss modulus, stress relaxation modulus and creep compliance of HTPB composite propellants are obtained through computer data and graphic processing on the basis of dynamic viscoelasticity tests.

Research Notes

Prediction of Sound Pressure Level around the Muzzle of Small Arms

Wang Bingyi、 Kang Zhenzhen

1991, 12(3):  60-63.  doi:10.3969/j.issn.1000-1093.1991.03.010

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Based on our study on the relation between the acoustic power of small armsˊ muzzle blast noise and the parameters of the muzzle, applying laws for the sound pressure level (SPL) of a point source in free acoustic field as well as directivity and attenuation laws of the muzzle noise, the author established a formula to describe the SPL of the muzzle noise. The SPLs of different kinds of submachine-guns, rifles and machine -guns with different ammunition charges are predicted in this way. Of these predictions, 93% have absolute errors within 1.5dB. The precision of the prediction satisfies the requirements of engineering design and muzzle- noise evaluation.

Computation of the lateral Force and Couple in a RocKet Nozzle

Zi Kun

1991, 12(3):  64-69.  doi:10.3969/j.issn.1000-1093.1991.03.011

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On the Shelf -Reliability of General Purpose Ammunitions

Qin Shijia

1991, 12(3):  70-75.  doi:10.3969/j.issn.1000-1093.1991.03.012

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In this paper a definition of shelf reliability is given， and procedures and methods for earring out the reliability evaluation for general purpose ammunitions are discussed. Mathematical models for the re?liability evaluation on a basis of success/failure and other ways of data processing are proposed.

Flash Radiography Investigation for the Process of Deformation of the Inert Plate in Shaped Charge Explosion

Gao Erxin、 Li Jingyun、 Liang Xiuqing

1991, 12(3):  76-79.  doi:10.3969/j.issn.1000-1093.1991.03.013

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Flash radiography was applied to study the deformation process of the inert plate and its velocity of deformation measured for the first time. The velocity of expansion of the shell vF, the collapse velocity of the liner v0, the jet velocity vj,the collapse angle β and the deforma?tion angle δ were also determined.

The Synthesis of Polynitrostilbenes

Sun Rongkang、Peng Xinhua、 Zhang Qingrong

1991, 12(3):  80-83.  doi:10.3969/j.issn.1000-1093.1991.03.014

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The synthesis of stilbsnes containing the nitro group were studied. The Shipp process is not applicable for the nitro-compounds used. Trinitro-m-toludine and trinitro-m-xylene were condensed with aroma?tic aldehydes to form stilbenes. Distyrylbenzenes containing the nitro group may be formed from trinitro-m-xylene. The procedure for the synthesis of 3，3ˊ-dinitrostilbene from m-nitro-benzaldeliyde and m-nitrophenylacetic acid via the Perkin reaction was found to be superior to that through the Meerwein reaction.

Effect of Rate of Pressure Change on the Combustion of Solid Propellants

Wang Junye、 Zhang Jiaxin、 Sang Bingcheng

1991, 12(3):  84-89.  doi:10.3969/j.issn.1000-1093.1991.03.015

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Based on a modified KTSS model, the numerical characteristics of the thermal-wave combustion models are investigated and numerical calculations are carried out for a wider range of |dp/dt|. The numerical solutions show that with higher values of |dp/dt|(in the original KTSS and will return to the steady value thereafter. Burning rate "runaway" is only a numerical difficulty but is not a solution to the thermal-wave combustion models. Meanwhile the predicted unsteady burning rates are compared with experimental results.

Influence of Surface Tension of Polymer Solutions upon the Impact Semsitiyity of PBX（Plastic Bounded Explosives）

Song Quancai、Wei huazhen

1991, 12(3):  90-93.  doi:10.3969/j.issn.1000-1093.1991.03.016

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In this paper the influence of surface tension of polyure? thane organic solution upon the impact sensitivity of PU-RDX (RDX coa?ted by polyurethane film) is investigated. The surface appearance of PU- RDX particles has been observed applying scanning electron-microscopy. The relation between surface apprearance of PU-RDX，surface tension of polju- rethane solution and impact sensitivity are discussed.

Application of Correlation Analysis in the Formulation of Worktime Norms

Wang xin

1991, 12(3):  94-96.  doi:10.3969/j.issn.1000-1093.1991.03.017

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The case of a manufacturing system turning out a variety of mass-produced pulleys in large quantities is analyzed, applying cor?relation analysis in the formulation of worktime norms，resulting in improvements of management effectiveness.