Table of Content

30 September 1986, Volume 7 Issue 3

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Paper

A Study on the Stability of Rod-nosed Projectiles

Yue Benxiang

1986, 7(3):  1-8.  doi:10.3969/j.issn.1000-1093.1986.03.001

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The paper discusses the flow field of a rod-nosed projectile and the factors affecting it，revealing the specific conditions of stability for the rod-nosed projectiles through experimental results, i. e. the stability of moment caused by eccentricity of axial force. The used in the experiments Macn numbers are 0.6?1.2，1.542，2.044 and 2.552.

Dynamic Characteristics of Sampling Systems by Variables with severity Adjustment

Tang Guoqing, Zhang Weiji

1986, 7(3):  9-19.  doi:10.3969/j.issn.1000-1093.1986.03.002

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Dynamic characteristics of sampling systems by variables with severity adjustment, such as the ISO 3951 . ANSI-Z-1.9，BS 6002 and DS05-30/1 sampling systems，are studied by using the method of generating functions。 Expressions of the transient，accumulative and final switching probabilities and expectation of the number of lots before switching are introduced. Numerrical calculations and theoretical analysis are also carried out using these formulae.

Analysis of Compressible Flow on High-Velocity Jet Penetration

Lin Xiao, Wang Jihai

1986, 7(3):  20-27.  doi:10.3969/j.issn.1000-1093.1986.03.003

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In this paper, using one-dimensional theory of the compressible fluid, we have put forward a method to solve and analyze the jet penetration on target. For different region of jetˊs velocity, we can get the corresponding configurations of subsonic or supersonic flows both in jet and in target, and work out the penetrating speed and depth easily. So, the method has a certain practical values. In the paper，we have also obtained an analytical expression of sound speed behind the shock, and a new index to evaluate tte compressibility of materials. These are of gre， at significances in the researches of high-strain rate phenomena.

Combinea calculation of Deformation and Stress for the Boay and the Sabot of an APFSDS

Qian Mingang

1986, 7(3):  28-34.  doi:10.3969/j.issn.1000-1093.1986.03.004

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A combined calculation for the body and the sabot of an Armour Piercing Fin-Stabilised Discarding Sabot(APFSDS)is discussed here by choosing the axisymmetric model and applying the substructure characteristic of the ASKA program； deformations and stresses in the APFSDS during the launching process are calculated. The radial and axial degrees of freedom of the coupled nodals of body and sabot are treated respectively, thus the computa-tional methods described in the literature are improved and more reasonable computational results are obtained, Not only are the deformation figures and the lines of equal stress for the body and the sabot obtained，but also the distribution curve o￡ loading between the body and the sabot, as given in this paper.

On tne Effect of Centering Error in the Mounting of Master Ball Upon the Measurement of Radial Motion of an Axis of Rotation

Li Jun

1986, 7(3):  35-40.  doi:10.3969/j.issn.1000-1093.1986.03.005

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The measurement concerning the radial motion of an axis of rotation is one of among the key items of measurement in mechanical engineering. An analysis is given to the effect of centering error of the mechanical mounting of the master ball in a digital measurement upon the radial motion polar plot of an axis of rotation. Here the selection of base circle radius and its effect upon the assessment of departure from roundness is discussed，and the corresponding curve is given. It is proved that i￡ the base circle radius can be made several decuples larger than the centering error upon the departure of roundness can be neglected.

On the System Availability of Some Periodically-used Systems

Tao Huacheng

1986, 7(3):  41-46.  doi:10.3969/j.issn.1000-1093.1986.03.006

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A new concept of periodically used systems is proposed. For several specific systems of this kind, formulae of initial system availability，average system availability in operating period and average time required for the system to enter into normal state of operation are given.

Comprehensive Reviews

Small Calibre Weapons Effects-mechanisms, Testing and Relations to International Law

Bo Janzon

1986, 7(3):  47-57.  doi:10.3969/j.issn.1000-1093.1986.03.007

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A fast projectile penetrating tissue transfers energy during its passage, mainly as pressure waves. They cause an expansion of the tissues around the missile trajectory，the “temporary cavity”，limited by the strength of the tissues. In elastic material, such as muscle, the cavity rapidly collapses again. Subsequent re-expansions and collapses may occur. Finally there will remain a permanent wound channel of similar size as the causing projectile. It will be surrounded by a zone of contusion ed，nonviable tissue, and by lacerations，which may reach far. The most important factor deciding the extent of tissue damage around the wound channel is the amount of energy transferred by the projectile to the tissues during passage-the “energy transfer characteristics”. Experimental evidence is presented，and additional findings are discussed, such as the presence of scale effects in wounding. A simple experimental model,allowing the determination of the energy transfer characteristics of a small calibre projectile, is described. It involves firing at blocks of tissue simulant，viz. a special，soft soap，at realistic ranges. The experiments do not require any sophisticated measuring equipment. In the 1899 Hague Declaration, a famous and widely recognised ban on use in war of bullets which “expand or flatten easily in the human body” was agreed. The most well-known projectile with such properties was the so-calledrtDum-Dumvbullet. Other relevant rules of International Law are presented. Later efforts to negotiate additional rules of international law, aiming to avoid unecessary increases of the wounding power of small calibre firearms, are discussed. The energy transfer characteristics of some modern assault rifle systems are presented and discussed in the light of military requirements and Inteinational Humanitarian Law.

Research Notes

Estimation of Bond Dissociation Energy in Conjugated Molecules from the π—bond Order

Xiao Heming, Wang Zunyao

1986, 7(3):  58-61.  doi:10.3969/j.issn.1000-1093.1986.03.008

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A simple approximate equation has been proposed in this paper. It can be used to estimate the bond dissociation energy of the covalent bond in conjugated systems from the π一bond order computed through the HMO methed. A contrast between the calculated results and values obtained from the references is presented. Some applications of the equation in the study of sensitiveness and stability are discussed.

A General Purpose Method for the Interior Ballistics Calculations of Solid Propellant Rockets

Xu YuWang

1986, 7(3):  62-68.  doi:10.3969/j.issn.1000-1093.1986.03.009

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Based upon principles of solid propellant rocfcts and quasi-one dimen- tional flow theory, on the basis of interior ballistics a set of general purpose equations has been established. These equations can be used to calculate the interior ballistics of single chamber solid propellant rocket motors with long tail tubes or mnltiple propellant charges, or for motors with long tail tubes as well as mulitiple propellant charges. General pu- pose equations for calculating the equilibrium pressures have also been derived. Results of computation based on this method are in good agreement with experimental results.