Table of Content

30 June 1994, Volume 15 Issue 2

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Paper

Natural Vibration of Spin Tube Gun with Multi-Lumped Masses

Rui Xiaoting， Qin Yingxiao,Zhao Hailin et al.

1994, 15(2):  1-5.  doi:10.3969/j.issn.1000-1093.1994.02.001

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The dynamic model of transverse free vibration of a spin tube gun with multi-lumped masses is developed. Exact analytical formulas for the natural frequency and modal of the gun are deduced. The exact relations among the dynamic and static frequency of a spin tube gun and the angular speed are obtained. Computer calculated results are given. Effects of the mass and position of lumped masses on the system frequencies are studied. It is pointed out that the effect of angular speed on the system frequencies is remarkable. Ways of reducing the fire dispersion of spin tube gun systems are given. These results provide a new theoretical base and technical methods for improving the system dynamic characteristics and fire accuracy.

Dynamic Analysis of a 7.62mm Machine Gun on a Simulated Elastic Trijpod Mount

Yin Renlong,Yan Huimin, Wu Xianghai

1994, 15(2):  6-12.  doi:10.3969/j.issn.1000-1093.1994.02.002

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Dynamic problems of a machine gun on a simulated elastic tripod mount are analysed ； a dynamic model of the machine gun system (including shooter，tripod and soil) having two degrees of freedom is established. As a typical case the dynamic characteristics of a 7.62mm caliber machine gun with its automaton are analysed. Re- sulte of computation are compared with that of experiment, from which some proposals are presented to enhance the level of development of machine gun systems.

Classification of Two-Phase Flow Equatioiis in Interior Ballistics and lntergranular Stress

Jin Zhiming,Yuan Yaxiong,Weng Chunsheng,et al.

1994, 15(2):  13-18.  doi:10.3969/j.issn.1000-1093.1994.02.003

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Following the theory on characteristics of first order quasi-linear partial differential equations, classification of the balance equations for two-phase flow in in?terior ballistics is discussed. The presence of intergranular stress in the propellant bed is a key factor that determines the classification of the balance equation. The paper also analyses qualitatively and quantitatively the intergranular stress of the propellant bed.

A System of Identification for the Atmosphere Parameter along the Trajectory of Rockets

Yang Xiaodong,Wan Chunxi,Yu Renshun

1994, 15(2):  19-23.  doi:10.3969/j.issn.1000-1093.1994.02.004

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Presents an approach using real-time data measured by a tracking-radar for the identification of atmospheric parameters along the trajectory of a missile so as to extrapolate its impact point. A method for correcting the firing data of successive fires in salvo is then suggested. A software system has been designed on the basis of the above methods. The accuracy of the mentioned system is studied through a series of digital simulations.

A Theoretical Study on Some Characters of Fuze Safety Systems

Fan Ningjun, Ma Baohua

1994, 15(2):  24-28.  doi:10.3969/j.issn.1000-1093.1994.02.005

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On the basis of the theory of fuze safety system and the method of state space analysis, the paper studies the identity between the dynamic characteristics of the system’s physical equation and its dimensionless normalization equation, the indepen?dence among all the safety elements, the retardation of the arming process in a safety system，as well as the equilibrium state and its stability. Strict definitions for these characters are the given. These characters and definitions provide a theoretical basis and effective methods for a study in more depth of the fuze safety system and its arming process.

Nonlinearity iii the Frequency Modulation fora FM Ranging Fuze and Its Correction

Zang Lijun

1994, 15(2):  29-32.  doi:10.3969/j.issn.1000-1093.1994.02.006

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Gives an analysis on the non linearity in frequency modulation when a var- actor modulates directly in a FM ranging fuze, and shows its influence on the precision of ranging. A method of correction is put forward, and its principle, circuitry and the CAD programming flowchart are given.

A Study of the Reliability of Electroexplosivd Subsystem U sing Monte Carlo Modelling

Ren Maosheng, Wang Dong sheng

1994, 15(2):  33-37.  doi:10.3969/j.issn.1000-1093.1994.02.007

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Describes computer simulation combining sensitivity statistic data and the Monte Carlo method in the process of evaluation for the reliability of electroexplosive subsystems, and a corresponding computer programme RMCEES. Two types of typi?cal electroexplosive subsystems have been studied，viz. the DC electric firing circuit for machine tool fire extinguishing (type I circuit), and the firing circuit for energy- storage capacitor used in fuzes (type Ⅱ circuit). Hundreds of thousands of simulation tests have been performed for the two types of systems using the programme RMCEES on a Super-XT computer. Based on,the parameters of the circuits, the estimated relia?bilities of the two systems are no less than 99. 9% and 99. 999% respectively. The programme also predicts that the controlled lower threshold for voltage of power supply is 4. 67 volt when the reliability of type I circuit is no less than 99. 99% , Futhermore, tlie programme RMCEES can be used in reliability estimation and prediction and pa?rameter optimization design of non-electric initiating subsystems (e. g. spring pin firing system ) and other similar systems.

ON the Methodology of Guidance Loop Design

Zhang Yun

1994, 15(2):  38-41.  doi:10.3969/j.issn.1000-1093.1994.02.008

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In this paper, existing methods of guidance loop design are first sum?marized from the point of view of methodology. Then essential features of the object of guidance are presented and the criteria of selection of the methods of guidance loop design are given. Existing methods of guidance loop design are exhibited and briefly ap?praised .Finally, laws of development and prospects of the methods of guidance loop design are discussed.

Investigation on a Nitrating Agent Consisting of Metallic Nitrates and Acetic Anhydride

Lu Chunxu, Cai Chun

1994, 15(2):  42-45.  doi:10.3969/j.issn.1000-1093.1994.02.009

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With Laser Raman spectroscopy, the active nitrating agent in a system of metallic nitrates and acetic anhydride has been shown to be nitronium. The Hammett equation for the nitration with this nitrating agent in an organic solvent has been estab- lished with the aid of gas chromatography, and the reaction constant has been obtained ρ = — 6. 24 . In this system good regioselectivity can be achieved mainly because of the existence of a porous support and the low dielectric constant of the reaction media.

THE DirectVSynthesis of Type I Hexanitrostilbene (HNS)

Lu Ming

1994, 15(2):  46-50.  doi:10.3969/j.issn.1000-1093.1994.02.010

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HNS- Ⅱ has so far been made by recrystallization of HNS- I . In this pa?per a direct preparative method for HNS-Ⅱ starting from hexanitrobibenzyl is reported， a process not reported heretofore in literature. Effects of agents for the improvement of crystallization habit and water on the process are discussed. Solvent recycling is studi?ed. This new method can be applied in industrial process.

Design and Implementation of a General Purpose Weapon Design Expert System

Wu Huizhong, Wei Zijie ,Cheng Yunsheng

1994, 15(2):  51-56.  doi:10.3969/j.issn.1000-1093.1994.02.011

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This paper discusses the necessity of developing a general purpose weapon design expert system, introduces its overall structure and its key techniques-integrated knowledge representation, multilevel knowledge acquisition, meta-level control stractegy, fuzzy comprehensive evaluation and similar priority proportionarity decision etc.，and then gives an example of gun barrel designed by the expert system.

Application of Techniques of Steulation in Human Controller Model Research

Song Cheng ling

1994, 15(2):  57-64.  doi:10.3969/j.issn.1000-1093.1994.02.012

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In this paper, the advantages of the simulation technique are briefly dis?cussed. Problems of existing models for the tracking systems in fire control systems are summed up and analysed. Relying on the advantages of simulation, a human controller strategy model is developed , so that the above said problems can be avoided. The valid?ity of the model developed is verified.

Probabilistic Boundary Eleihent Method for Analysis of Static Responses of Structures with Stochastic Shape

Liu Hanbing, Chen Suhuan, Chu Ride

1994, 15(2):  65-69.  doi:10.3969/j.issn.1000-1093.1994.02.013

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This paper presents a probabilistic boundary element method for analysis of structural responses to static loads, when the shape parameters of structures are considered as tandom variables. We can use this method to calculate the mean values and standard deviations of the responses，and estimate the stochastic errors of structural characters resulting from the fabrication errors.

Comprehensive Reviews

A Review of Rasearches on Mischmetal Incendiary Agents

Jia Huiping

1994, 15(2):  70-74.  doi:10.3969/j.issn.1000-1093.1994.02.014

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Researches on mischmetal incendiary agents are reviewed. Because of its active chemical properties, low ignition point and high combustion heat, mischmetal is fit for use as pyrophoric incendiary agents. Mischmetal incendiary agents can be devid- ed into two kinds, the composite type and the alloy type. Mischmetal incendiary agents are usually used to provide explosive, killing , or armor-piercing munitions with incendi?ary ability. The targets of such munitions are e. g. fuel tanks of military trucks or air?crafts ,and other combustibles or personnels. Research and application of mischmetal incendiary agents are becoming mature. China is rich in mischmetal resources. The search for more effective mischmetal incendiary agents with special properties should be a direction in the development of incendiary agents.

Experimental Techniques and Analysis

AN Experimental Study of thie Secondary Flow in a Nan-T ip-off Rocket Launch TUBE

Cao Chongyong,Fang Yi,Zhang Fuxiang

1994, 15(2):  75-77.  doi:10.3969/j.issn.1000-1093.1994.02.015

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A static simulation experiment for a non-tip-off rocket launch tube has been carried out, making use of the theory of local dynamic similiarity. Some ex?perimental work on the secondary flow within the launch tube has been done, and char?acteristics of the secondary flow in the annular gap between the rocket body and the launch tube have been clearly elucidated.

Research Notes

ON the Design of Adaptive Zoom Systems and Passive Distance and Velocity Measurement for Image Guided Missiles

Yang jun,Xiong Yan,Xu Yan,et al.

1994, 15(2):  78-80.  doi:10.3969/j.issn.1000-1093.1994.02.016

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No distance measuring devices are installed in a typical image guided mis?siles. This leads to uncertain of parameters in the zoom control loop of the missile. This paper uses the modeトreference adaptive-control method in synthesising the zoom con?trol system. Besides , the passive distance and velocity measuring of targets is realized through the use of sufficient exciting signals. Finally, a design example is given to demonstrate the validity of the proposed method.

Three-Dimensional Analysis of " Flow Turning" in the Combustion Stability Theory for Solid Propellant Rocket Motors

Gao Ye

1994, 15(2):  81-87.  doi:10.3969/j.issn.1000-1093.1994.02.017

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With the assumption of ” Yn , a three-dimensional model is obtained for the linear acoustic combustion in a rocket motor. The one-dimensional model obtained from the Y-three-dimensional model is in excellant agreement with the one-dimensional analysis by Culick. Many new opinions of the one-dimensional model by Culick ,such as " Flow turning" term, also exist in the Y-three-dimensional model.

Singular Value Decomposition for the Dynamic Analysis of Multibody Systems with Rheonomic Constraints

Shui Xiaoping

1994, 15(2):  88-92.  doi:10.3969/j.issn.1000-1093.1994.02.018

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In this paper, the composite coordinates are defined using singular value decomposition of the constraint Jacobian matrix. Starting with Lagrange equations of the first kind，pure differential equations of muitibody systems with rheonomic cons?traints are established. The process of the numerical dynamic analysis is also given. One example is finally presented.

Analytical Computation of Damages and Coflxptitfii Emulation of Processes of Failure for Machine Parts

Sun Wenhuan, Wang Mohu

1994, 15(2):  93-96.  doi:10.3969/j.issn.1000-1093.1994.02.019

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Maximum tangential stress criterion, energy release rate criterion ? and minimum strain energy density factor criterion in fracture mechanics are made use of with the aid of a computer, in locating the dangerous point of machine elements under specific loads and the direction of propagation of fatigue crack in machine elements under repeated load. Thiough this the damage position and the dynamical process of the crack propagation of machine elements can be simulated with the computer by means of the finite element method (FEM). Practical examples which have been com?puted and displayed include the mechanical models of the cases of a centre-and edge- cracked plate In tension. Crack growth and process of propagation of bending fatigue crack in gear teeth and tenon teeth of a turbine wheel have been simulated. 丁he results are basicaly In coincidence with the actual damage situation. The computation and simulation of the damage process are meaningful In furnishing guidance toward the removal of trouble spots and toward a refined design of machine elements.