Table of Content

29 June 1991, Volume 12 Issue 2

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Paper

A Model for the Estimation of the Effectiveness of Small Bore Shells Meant for Internal Blast： the Optimum Design of Shell Parameters

Gao Xiuzhu、Jiang Haozheng

1991, 12(2):  1-7.  doi:10.3969/j.issn.1000-1093.1991.02.001

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The paper discusses a model for estimating the effectiveness of anti-aircraft small bore shells meant for internal blast and deals with the optimum selection of shell parameters. The vulnerable area is used in the case of internal blast as the measure of effectiveness. A model for estimating the vulnerable area is established, using the case of 37mm frag- mentation-blast shell shoots at a models of aircraft as a concrete example for the calculation. The results show that the optimum explosive charge for t1ne 37mm fragmentation-blast shell is about 120 gram, a value rather close to those used on shells of similar calibre abroad. This model can be used to conduct scheme demonstration and preliminary design as well as evalution of small bore fragmentation-blast shells.

A Tentative Proposal for a Theory of Fuze S & A Environment Recognition

Gao Min、Ma Baohua

1991, 12(2):  8-14.  doi:10.3969/j.issn.1000-1093.1991.02.002

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This paper endeavors to give some basic concepts of fuze S & A environment recognition on the basis of which the performance of the traditional S & A systems is analyzed- It puts forward the information theory aspects concerning S & A environment recognition，and classifies the S & A environment recognition into environment detection and pattern re?cognition. Based on a brief description of the information theory aspects concerning S & A environment recognition， the information value of environment con?dition is defined. Taking into account the relationships between the infor-mation source? the method of recognition，and objectives of the environment recognition device, a theoretical model is developed and formulae for quan?titative evaluation of the information values are deduced. The paper sets up a criterion of evaluation for environment detection and analyzes the conceptual basis of design in traditional S & A. A general description is given on pattern recognition and three basic principles are formulated.

Method for Determining the Reliability Indices of Fuzes

Wang Cuizhen

1991, 12(2):  15-19.  doi:10.3969/j.issn.1000-1093.1991.02.003

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Determination of reliability indices of products or systems is one of the tasks in reliability engineering. Proper selection and determina?tion of the indices will secure a sound foundation for the reliability of products or systems. The paper discusses the importance of determining the reliability index of a fuze system in the course of reliability design,, the peculiarities of re?liability index of fuze products，varieties of reliability indices of a fuze system, and procedures, methods and principles involved in determining the reliability indices of fuze systems.

Detecting Electrodes for Capacitance Fuzes

Li Jianxin、 Xu Qingquan 、Shi Jusheng

1991, 12(2):  20-27.  doi:10.3969/j.issn.1000-1093.1991.02.004

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The design of detecting electrodes in a capacitance fuze is a critically important factor that determines its sensitivity. Capacitance fuzes base their operation on the laws of static electric fields. The projectile, the electrodes，and the target are here taken as a 3-conductor .system， upon which the physical model and mathematical model are built up， permitting one to calculate and analyze the conductor system using the charge simula?tion method. Electrodes and projectiles having different shapes and sizes were then put under test. Synthesis of the results of theoretical analysis and tests results in a design principle for detecting electrodes. With this principle the design of a detecting electrode for use on a 152mm projectile is finally given as an example.

Modeling of Air Targets of Proximity Fuzes

Fang Zaigen 、Sun Yilan、Lin Kongjian、 Huang Xiaomei、 Zhang Pengfei、 Chen Fangxing

1991, 12(2):  28-31.  doi:10.3969/j.issn.1000-1093.1991.02.005

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This paper presents the modeling of air targets of proximity fuzes using experimental data. The target model consists of many scattering points. The determination of their numbers, positions relative to the gravi?ty center of the targets and cross sections are directly based on the analysis of a great number of scattering data obtained from sxperiments. The com?bined model has been established adopting the methods of non-linears ystem identification and interpolation. VVlien the intersection conditions of the fu?ze and the target are given, the scattering signal can be obtained using the combined model. Statistical tests show that the fitting precision of the mo- del is satisfactory and that it can well be used in fuze design and system si?mulation.

The Design of a Digital Filter and Itf Applications in the Simulation System for Proximity Fuzes

Hong Baoming、 Li Zaiting、 He Zunwen

1991, 12(2):  32-40.  doi:10.3969/j.issn.1000-1093.1991.02.006

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The paper gives a design for digital bandpass filters. The de?signed filter can automotlcally accomplish the desired task according to tar?gets assigned. It can provide not only the required magnitude of frequency response, phase response，transfer function and output response，but also the filterˊs parameters in cascade or paralled form. The paper discusses also the digital filterˊs applications in the simulation of proximity fuzes，giving sa?tisfactory results through simulation analyses.

Study of Two-Dimensional Flow and the Shock Detonation Transition (SDT) in a Detonator

Jia Quansheng、 Chen Fumei、 Wang Tingzeng

1991, 12(2):  41-48.  doi:10.3969/j.issn.1000-1093.1991.02.007

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The 2D initiation flow in a detonator is measured using an im?proved 2D composite manganin-constantan ring gauge. The SDT of the de?tonator is simulated with the codes 2DLE and BKW. Feasibility of the 2D Lagrangian gauge and the code 2DLE in research applications concerning de?tonators is verified through comparison of experimental data and computed results.

An Investigation on the Axial Initiating Ability of Plain Bottom Detonators

Cai Ruijiao、 Mao Jinsheng

1991, 12(2):  49-55.  doi:10.3969/j.issn.1000-1093.1991.02.008

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The axial initiating ability of a detonator is one of tlie im?portant parameters among its properties. The present paper studies the axial initiating ability of plain bottom detonators by deducing the shock wa?ve velocity and the fragment velocity both theoretically and experimentally. It is found that the initiating ability of plain bottom detonators，within a certain distance, is the result of actions of the two main factors，namely the shock wave and fragments. Since the velocity of the shock wave decays with time and the velocity of the fragments at first accelerates in an undulating manner and then decays， the plain bottom detonator has itfj minimum output somewtere not too distant from the bottom of the de?tonator and a maximum output at some farther distance. The techniques for theoretical calculation and experimental measurements are presented and tlie results discussed.

A Tentative Analysis of the Safety of Industrial Detonator Production Lines

Liang Junyan、 Wang Peilan、 Liu Weiqin

1991, 12(2):  56-62.  doi:10.3969/j.issn.1000-1093.1991.02.009

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Fault tree analysis method (FTA) in system safety engineering is used in this paper to analyse the safety in industrial pdetonator roduc- tion lines. Construction of the fault tree for the production line and formation of the computer analysis program are introduced，and results of analysis on a portion of the production line are given. The analysis can only be tentative for it requires much work to collect the basic data.

Ihe Phenomenon of Transition in Thermal Explosions and Calculation of the Transitional Points

Du Zhiming、 Zeng Qingxuan、 Feng Changgen

1991, 12(2):  63-70.  doi:10.3969/j.issn.1000-1093.1991.02.010

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In this paper, critical and transitional iconditions are in - troduced，according to a generalized definition of criticaiity and tran?sition of stationary~state systems. A new method for the solutions at transition for a system with generalized heat transfer conditions (Tho?mas systems) is given, using a specific method for non-linear numeri?cal intergration and the Newtonian iteration. Calculated results of tran?sitional values are given in the paper for slabs，cylinders and spheres. The advantage of the present method is that when the Blot number o (close to a Semenov system), it gives precise results, overcoming the shortcomings of other methods.

Rheological Properties of TNT/RDX Suspensions

xu Gengguang、 Xu Junpei

1991, 12(2):  71-74.  doi:10.3969/j.issn.1000-1093.1991.02.011

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The distribution of RDX particles and the rheological pro?perties of liquid state TNT and TNT/RDX suspensions are studied. Effects of the different additives on the rheological properties of TNT/ RDX suspensions is also discussed. The results will furnish a theoreti?cal and experimental basis for tlie improvement of COMP B products.

Characteristics of Attenuation of Shock Waves in Barriers of Different Materials

Chen Xirong、 Wang Ke 、Liu Derun、 Wu Fengyuan

1991, 12(2):  75-80.  doi:10.3969/j.issn.1000-1093.1991.02.012

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Barrier length (or gap thickness) has been used to represent the comparative sequence of shock sensitivity of different explosives. In this work，in order to calculate the shock pressure at the end of a barrier whose thickness represents the sensitivity of a charge， a simple but effective experimental set-up is presented for the measurement of the shock velocity in the barrier. With this measuring s],stem can be obtained fair display of the transmitting wave，with a high responce rate and a large amount of available data points of instantaneous value. In the present method, trails of propagation of shock waves in different barriers are first measured with precision, and the shock velocities are derived from the differentials of the trails. The shock pressure under any specific condition is calculated from the shock velocity with the Hugoniot equation of the material. Shock velocity and pressure attenuation versus distance in some barrier materials such as Ly-12A1,plain carbon steel#45，and plexiglass were obtained and compared with each other.

Experimental Techniques and Analysis

A Method for Medium Range Pressure Shock Measurements Applying a Piezoresistive Transducer Couple

Huang Zhengping、 Feng Xichun

1991, 12(2):  81-85.  doi:10.3969/j.issn.1000-1093.1991.02.013

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In this paper, a new method of medium range pressure shock measurements using a couple of piezoresitive transducers is described The method expands the operating range of low—resistance pressure gages. The range of measurement of the method extends from about 0.2 GPa to 4 GPa. Pressure resolution can reach 20 MPa.

Experimental and Theoretical Study of a New Millimeter Computerised Tomography Non—Destructive Testing System

Zhao Chuandong

1991, 12(2):  86-92.  doi:10.3969/j.issn.1000-1093.1991.02.014

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A new millimeter wave CT system is set up and studied, applying the plane wave diffraction CT principle to perform non-destruc- tiye tests for dielectric materials. In order to generate the required plane wave front and comparatively narrow beam of illumination, an offset para?bolic antenna in conjunction with a null bridge system has been designed and setup. Some experimental results of reconstructed images for objects under test are given under frequency of 30GHz.

Research Notes

Dynamic Analysis of a Fuze Having a Weak Section When Penetrating a Target Plate

Gao Shiqiao、 Wang Baoxing

1991, 12(2):  93-96.  doi:10.3969/j.issn.1000-1093.1991.02.015

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In this paper are analyzed the dynamic characteristics of a fuze having weak sections when penetrating a thin target plate. It is seen that the lower the stiffness of the weak section, the smaller will be the force exerted on the fuze at the instant.