Table of Content

31 December 1987, Volume 8 Issue 4

Previous Issue    Next Issue

Paper

Source of Muzzle Blast Noise and Its Physical Characteristics

Wang Bingyi

1987, 8(4):  1-9.  doi:10.3969/j.issn.1000-1093.1987.04.001

Asbtract ( )   PDF (10608KB) ( )  

References | Related Articles | Metrics

Properties of muzzle blast noise as detected at tlie gunner's position are first described with the aid of the theory about the muzzle flow field and that of the blocking jet noise, am analysis for the generation of muzzle blast noise is made making use of available test date，It is reasoned and then verfied that the muzzle shock wave is the chief source of muzzle blast noise. From experimental study, all the physical characteristics of muzzle blast noise such as the acoustic power, pressure level，directivity，time characteristics, freguency spectrum and so on are systematically analyzed. Some unique conclusions about muzzle blast noise are obtanied and some regular patterns similar to blocking jet noise is found.

Two-Phase Flow Interior Ballistic Model in the Propellant Beds with Centre Core ignition and Its Numerical Solution

Wang Shengchen、Zhou Yanhuang

1987, 8(4):  10-19.  doi:10.3969/j.issn.1000-1093.1987.04.002

Asbtract ( )   PDF (11082KB) ( )  

References | Related Articles | Metrics

The purpose of this paper is to predict precisely the ignition and combustion phenomena that occur in high-pressure antitank guns with centre core ignition and combustible cartridge. Two sets of quasi—one-dimen- sion unsteady two-phase flow interior ballistic models are represented,which are coupled and applied to the propellant beds and the centre ignitron respectively. The equations are calculated by using finite difference methods. Some comparisons between the theory and experiments show that the theory accords quite well with the results of the experiments. According to the results of the prediction some suggestions concerning the charge configuration have been presented.

Nonlinear Stability of Gyroscopic Systems

Zhang Guangshu

1987, 8(4):  20-26.  doi:10.3969/j.issn.1000-1093.1987.04.003

Asbtract ( )   PDF (8182KB) ( )  

References | Related Articles | Metrics

According to the direct method of Liapounov the stability problems of gyroscopic systems acted on by nonlinear dissipative forces and nonlinear conservative forces are discussed in this paper. The stability criteria for nonlinear gyroscopic systems is obtained in the case of large disturbance. The results show that the stability criteria for linear systems is also valid to nonlifiear systems except the critical case.

Sequential Sampling Inspection and Itˊs Application in Acceptance Tests for the Density of Impact Point of Rocket

Wang Yong

1987, 8(4):  27-36.  doi:10.3969/j.issn.1000-1093.1987.04.004

Asbtract ( )   PDF (10741KB) ( )  

References | Related Articles | Metrics

The basic principle and procedure of sequential Sampling inspection are discussed and the method of making the sequential sampling inspection plan equivalent to the original one is described，using the acceptance test for the density of impact point of a rocket as an example。 Four sequential sampling inspection plans, which are equiva-lent to the original one，are proposed。It is proved by Monte-Carlo simulation that the average sample quantity needed for some of the Sequential sampling inspection plans is 17%-81%less than for the original one，with variable values of standard deviation o from individual fatch of product. It has also been proved by the acceptance records of 133 batches of products from a factory during the period of four years that more than 39% of the total number of sample quantity needed for the original plan can be spared.

Experimental Techniques and Analysis

Analysis of TNT，RDX9 DNT and DNN in industrial Waste Water by Using Capillary Column Equiped with ECD

Tian Linxiang、Fu Ruonong

1987, 8(4):  37-43.  doi:10.3969/j.issn.1000-1093.1987.04.005

Asbtract ( )   PDF (8016KB) ( )  

References | Related Articles | Metrics

In the present paper a method for separation and determination of explosives in waste water is described. The samples were extracted with benzene and the extract was injected in-to the gas chromatograph equiped with a ECD and fused silica capillary column. Tke explosive including 2，4-dinitrotoluene(DNT),trinitrotoluene(TNT), hexogen(RDX) and dinitro-naphthalene (DNN) can easily be separated on the capillary column and detected with ECD. Operating conditions are as follows： Apparatus:Model Sp-2308 gas chromatograph equiped with Ni-63 ECD. Column:Fused silica capillary column(21m X 0.25mm)coated with OV-101 Column temperatures 190°C Carrier gas flow rate： 1.85ml/min Injection tempreature： 250°C Split ratio： 1:69

A Single-Microphone Method for Acoustic Intensity Measurements

Sun Fengchun、Zheng Muqiao

1987, 8(4):  44-49.  doi:10.3969/j.issn.1000-1093.1987.04.006

Asbtract ( )   PDF (6811KB) ( )  

References | Related Articles | Metrics

The paper proposes a Single Microphone Method，based on the two- microphone cross-spectral method, for sound intensity measurement. Under a free or semi-free sound field condition, the influence of sound field and background noise was analyzed. Intensity and source power with and without background noise were tested. A program was written and computation carried out，The result proved to be satisfactory.

Application of XPS and SIMS to the Study of Combustion Theory of Solid Propellant

Ma Qingyun、Yang Rongjie

1987, 8(4):  50-55.  doi:10.3969/j.issn.1000-1093.1987.04.007

Asbtract ( )   PDF (13379KB) ( )  

References | Related Articles | Metrics

In this paper the surface property of combustion catalyst (Chromic Oxide) is stydied by XPS and SIMS, and its effect on the catalysis of AP is measured. It is evident that calcined Chromic Oxide enhances the combustion catalysis due to the change of surface proprerty.

Research Notes

Incremental Analysis of Elasto-Plastic Material and Extremum Theorems

Du Sentian

1987, 8(4):  56-59.  doi:10.3969/j.issn.1000-1093.1987.04.008

Asbtract ( )   PDF (5892KB) ( )  

References | Related Articles | Metrics

This paper deals with the incremental boundary value problem for elasto-plastic work-hardening material when thermal strain rates are taken into consideration. Moreover two extremum theorems are deduced by means of , the quadratic functionals。

An Experimental Investigation for the Axial Distribution of Initial Velocity of Shells

Feng Shunshan、Cui Binggui

1987, 8(4):  60-63.  doi:10.3969/j.issn.1000-1093.1987.04.009

Asbtract ( )   PDF (5893KB) ( )  

References | Related Articles | Metrics

Initial velocity of steel she11s with various charge structures have been measured by using flash x-ray photography system. As the result of data processing, an engineering anlysis for the distribution of initial velocities along the sheel axis is presented. This approach applies to fragment warhead with general charge structures under three different initiation patterns,

The Exterior Ballistic Optimum Design for Anti-Aircraft Projectiles of Small Calibers

Wang Zhongyuan

1987, 8(4):  64-68.  doi:10.3969/j.issn.1000-1093.1987.04.010

Asbtract ( )   PDF (5497KB) ( )  

References | Related Articles | Metrics

The design for an anti-aircraft projectile，provided with ample power and precision， to affain a given slant distance with the shortest possible spent time，is a problem of much practical interest. This paper gives a mathematical model for such an optimum design of anti-aircraft projectiles and，applying methods of mathematical programming，suggests a computer software for the design，Selected examoles proved the parctica- bility of the optimum design.