Table of Content

31 March 1993, Volume 14 Issue 1

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Paper

Sensitivity Aaalysis and Dymamic Modification of Machine Guns

Jin Tianyou,Wang Jianzhong

1993, 14(1):  1-5.  doi:10.3969/j.issn.1000-1093.1993.01.001

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In this paper, the relationship between variations in structural parameters and dynamic characteristics of machine guns is analysed quantitatively with the method of sensitivity analysis，and the sensitive points and relevant parameters of the machine gun are found. On this basis, these sensitivity parameters can be modified through optimization and an optimum design of the dynamic characteristics of machine guns is obtained.

Theoretical and Experimental Exploration of tlae Velocities Components after an Coaxal Impact

Shi Ruiming,JinZanguo

1993, 14(1):  6-12.  doi:10.3969/j.issn.1000-1093.1993.01.002

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In the paper, the velocities of arbitrarily shaped components after positive impacts with each other are calculated using a computer program reflecting the materials’ properties, shape, cross-sectional area，length and velocities before collision，based on the theory of stress wave and the principle of conservation of momentum. Errors between the computed velocity and that from practical tests are found to be less than 5%.

Projectile's Motion Touching the Wall of Increasing Twist Rifled Bore

Rui Xiaoting,Liu Yafei

1993, 14(1):  13-16.  doi:10.3969/j.issn.1000-1093.1993.01.003

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Differential equations of an unsymmetrical projectile’s motion touching the wall of a flexible increasing twist rifled bore with the bourrelet are developed. The patterns of a symmetrical projectile’s motion touching the wall of an ideal increasing twist rifled bore with the bourrelet are studied and compared with that of a projectile traveling in a uniform twist rifled bore.

Influence of Ignition System on Pressure Waves within Bores一Experimental Study and Numerical Simulation

Jin Zhiming,Weng Chunsheng,Yuan Yaxiong

1993, 14(1):  17-23.  doi:10.3969/j.issn.1000-1093.1993.01.004

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A new ignition system where a two layered centre core ignition system having a pyrotechnic composition is given. Based on the characteristics of the new ignition system, two sets of quasi-single-dimensional two-phase flow interior ballistic models are set up that are applicable to the propellant bed and the centre core ignition system respectively, as well as a model for the volumetric rate of burning gas ejected from nozzles of the pyrotechnic composition, comparisons between theory and experiments show that the theory accords well with the results of experiment. Both experimental results and theory point to the fact that the new ignition system is effective in suppressing the pressure wave.

Axisymmetric Two-Dimensional Two-Phase Flow Model of Interior Ballistics for a Large Caliber Smooth Bore Gun and Analysis of Its Calculation Results

Zhou Yanhuang,Liu Qianli,Wang Shengchen

1993, 14(1):  24-30.  doi:10.3969/j.issn.1000-1093.1993.01.005

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This paper presents an axisymmetric, two-dimensional theoretical model for the interior ballistic two-phase flow, as well as the calculation results by computer coding based on this model, for a large-calibre smooth-bore gun. Emphasis of this simulation is on the flame-spreading process in the early interior ballistic cycle, especially on the effect of the radial flow on axial results. The results of simulation are supported by the experimental results on the gun.

A Digital Generatioia Method for the ReMote control Command of a Spinning Missile

Sun Dianquan

1993, 14(1):  31-35.  doi:10.3969/j.issn.1000-1093.1993.01.006

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In this paper, the digital generation method for the remote control command of a spinning missile is discussed in some detail. Problems that need to be resolved for a single CPU digital controller system are analyzed. Based on a 8-bit microprocessor the principle of digital generation of the control command is illustrated.

A New Virial Eqpation of State and Its Application in Gun Propellant Gas Calculations

Yu Yuhua,Cao Guitong,Wu Shannan,QuYongde

1993, 14(1):  36-41.  doi:10.3969/j.issn.1000-1093.1993.01.007

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Based on the kinetic theory and collision theory of molecules, molecular interactions occuring during three-molecule collisions are discussed and a new, simplified reduced virial equation of state is proposed. With it pressures of gun propellant gases in high pressure ciosed-bombs have been calculated. The results are found to be better than those obtained from other forms of equations of state and agree fully with experimential data.

Morphologieal Structures and Fracture Mechanisms of Gun Propellants during Impact Fracture

Hu Guosheng,Zeng Zhaohuang,Luo Yunjun, Zhang Lihua,Niu Bingyi

1993, 14(1):  42-46.  doi:10.3969/j.issn.1000-1093.1993.01.008

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Gun propellants in the process of use are subjected to impact forces. In this article, the morphological structures of Izod impact fractured surfaces of several gun propellants are studied. The results showed that the homogeneous single base and non- homogeneous nitramine or nitroguanidine triple base gun propellants have different morphological structures and modes of fracture by the action of impact load and under conditions of different temperatures. At lower temperatures, fracture is caused by cracking of the fibers within the NC fiber bundle for the single base gun propellant，and by the more serious stress concentration as a result of large RDX crystal grains breaking in the NC binder for the nitramine gun propellant, and by the crack of adhesion interface between the NC binder matrix and the NQ crystals for nitroguanidine gun propellants. At higher temperatures, fracture is caused by the formation of original craze to final cracks within the NC fiber and by the microfiber slipping for the single base gun propellant, and by improper wetting and presence of gaps between the adhesion interfaces for the nitramine or nitro- guanidine gun propellants. In addition, some suggestions are provided specifically as to ways of improving the impact fracture behaviour of nitramine and nitroguanidine gun propellants.

Finite Element Analysis of a Mechanical Autofrettage Process as an Elasto-Plastic Contact Problem

Chang Liangming,Wang Xucheng

1993, 14(1):  47-51.  doi:10.3969/j.issn.1000-1093.1993.01.009

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Mechanical autofrettage process is an efficient approach to enhance the elastic carrying capacity and prolong the fatigue life of gun barrels and high pressure vessels. In this paper, based on the Mixed Variable Method and Path-Independent Algorithm proposed by the authors，the finite element analysis of a mechanical autofrettage process as an elasto- plastic contact problem is presented, showing that results in better correspondence with conditions actually in existence can be obtained.

On the Mechanism of Chatter Suppression with High Freqency，Vari-Speed Unseparated Type Ultrasonic Vioration Turning

Yu Jin,Zhou Xiaoqin

1993, 14(1):  52-57.  doi:10.3969/j.issn.1000-1093.1993.01.010

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The paper gives an analysis of the high frequency vari-speed characteristics in the unseparated type ultrasonic vibration turning (UVT) and proposes a mechanism of chatter suppression with the unseparated type UVT. This has been verified by our test results. The mechanism proposed is a break through against the theory for convensional UVT.

Comprehensive Reviews

A Review of Research Programs，Charaeteristics and Trends on Modem Ballistics

Ma Dawei

1993, 14(1):  58-65.  doi:10.3969/j.issn.1000-1093.1993.01.011

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In this paper, the main research programs of each ballistic branch are discussed. It is suggested that new propulsion tachnologies, including liquid propellant gun， electrothermal-chemical gun and electromagnetic gun, and hypervelocity projectiles will be the main lines that will promote the development of ballistics. This challenge will bring along significant progress of weapon systems in their principles and technologies. It is also expounded that the methods and techniques of ballistic system research, computer control and simulation, weapon lethality and vulnerability will be the salient characteristics of ballistic research.

Research Notes

Optimization Design on the Basis of Fatigue Life for Elements of a Blocking Mechanism

Huang Wei,Zou Yida

1993, 14(1):  66-69.  doi:10.3969/j.issn.1000-1093.1993.01.012

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By correlating the dynamic stress calculation and the fatigue life analysis of an element on a blocking mechanism, and from the point of view of working life, a simple optimization design method for an element on a blocking mechanism is put forward. This makes it possible to design quantitatively the local position dimensions of localities having stress concentration in the element. Application of the method on a design shows that the results are reliable, and that the method can furnish guidance to practical engineering designs.

Measurement of Bullet Eccentricity by Torsion Pendulum Method

Chen Xianlong,Ding Caiyun

1993, 14(1):  70-72.  doi:10.3969/j.issn.1000-1093.1993.01.013

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In this paper is introduced a new method for the measurement of bullet eccentricity utilizing a torsion pendulum having double taut strings clamped at both ends. Actual use has demonstrated that the appratus can accurately measure the eccentricities of various bullets, especially for those having calibres under 37mm.

A New Approach for the Investigation of the Scattering Characteristics of Radio Fuze Targets with the Transient Electromagnetic Field

Yang Liming

1993, 14(1):  73-76.  doi:10.3969/j.issn.1000-1093.1993.01.014

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The transient electromagnetic field method for target recognition has made its appearence for only a few years. The author endeavoursin its application in the scattering characteristics investigation of radio fuze targets。A feasible research plan is presented. It is here endeavoured also to solve the problem of extracting target information from a complicated noise background in this way.

Numerical Simulation of Explosive Initiation by Different Sized Flying Plates

Liu Jupeng,Chen Fumei,Jin Quansheng

1993, 14(1):  77-83.  doi:10.3969/j.issn.1000-1093.1993.01.015

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The initiation of explosive PBX- 9404 by flying plates is simulated using Lagrange-Euler finite difference program. Three detonation phenomena are obtained under different conditions and the influence of velocity and area of the flying plates to the computational results is reported.

On the Practicable Courses to Achieve Effectiveness of Fireballs

Jin Huiping,Chen Qin

1993, 14(1):  84-86.  doi:10.3969/j.issn.1000-1093.1993.01.016

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Former researches on fireballs in causing incendiary combustion are reviewed and the requirements of fireballs causing effective damage or killing put fore ward , i. e. heat flux ≥ 4 Cal/cm2 ? s, duration≥ 2s. Through an analysis on the probabilities of several ways to achieve effective fireballs based on experiments，it is found that increase in the amount of incendiary agent used is a practical means for its realization.

Bulk Modulus and Bulk Creep of Solid Propellants

Zhao Bohua,Xin Zhenhe,Shen Yueping

1993, 14(1):  87-91.  doi:10.3969/j.issn.1000-1093.1993.01.017

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Minute bulk deformations in samples have been measured with accuracy under different pressure loadings. Experimental curves of bulk deformation versus pressure as well as the bulk modulus, initial void content for two solid propellants have been obtained through analysis and subsequent processing. Creep curves of one solid propellant under constant pressure have also been obtained. The paper will be useful to structural integrity analysis of grains and to a study of the service life of solid propellants.

An Improvement in the Method of Repeating Identical Substructures with the ASKA Program System

Li Ruixing

1993, 14(1):  92-96.  doi:10.3969/j.issn.1000-1093.1993.01.018

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In this paper,necessary conditions and method of implementation of repeating identical substructures in using the ASKA program system are summarized. some situations not realizable in ASKA for repeating identical substructuers are analized and a method for its realization is presented.