Table of Content

30 June 1993, Volume 14 Issue 2

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Paper

A Study and Experiments on Air-Charged Floating Vessels with Open Bottom

Zhang Shengtao, Li Huiyou, Xiong Kefang

1993, 14(2):  1-6.  doi:10.3969/j.issn.1000-1093.1993.02.001

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This paper presented the concept and structure of an air-charged floating vessel with open bottom. The authors have performed scale model experiments and proved that the Archimedes’s principle applies also to the air-charged floating vessel with open bottom. Dynamic air-charging with this new structure permits a certain amount of allowable damage area so as to guarantee a reliable continued voyage. The study foresees a good perspective in engineering applications in such respects as increased buogancy, survivability and decreased dimension for amphibious vehicles.

Impact Fatigue Strength Design of the Locking Lug of Bolts and an Approach fbr the Estimation of Its Life

Wang Xueyan, Song Guanghui, Shi Xiaojing

1993, 14(2):  7-14.  doi:10.3969/j.issn.1000-1093.1993.02.002

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Through an analysis of the working loads and calculations for the rate of strain on the fracture positions on a bolt, the paper shows that the nature of loading on the bolt Is a repeated pulsating impact load. Using the fatigue theory and measurements on samples of plane stress bolts, it shows that bolt failures result from impact fatigue, Present situations on the study of impact fatigue intensity would suggest that a simple and direct way to the impact jfatigue strength desiga and life estimation for the locking lug of bqlts is by means of simulation tests in conjunction with empirical formulas. Moreover, as a supplementary method, the revised langer method is introduced.

Relatioms Between Forces and Deformations of Fopr-Foint Contact Bearings in 5 Degrees Of Freedom

Lin Lizong

1993, 14(2):  15-20.  doi:10.3969/j.issn.1000-1093.1993.02.003

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The single-row four-point-con tact ball-type slewing bearing is adopted in a type of anti-air gun. It plays an important role in the mechanical characteristics of the guru The influence of the bearing on the firing accuracy should be investigated carefully because of the complexity of the contact problem. This paper derives out the relationship between the deformations and the external loads in terms of the Hertzes theory. The firing bias of the gun caused by the horizontal rotating slewing bearing is estimated from a view point of statics and is shown to be a small quantity.

Launching. Dynamics Analysis of an Ejector Launched Anti-Tank Missile

Fang Yuanqiao, Chen Ming, Song Tinglun

1993, 14(2):  21-26.  doi:10.3969/j.issn.1000-1093.1993.02.004

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On the basis of theoretical analysis and testing, a launching dynamics analysis with an accompanying random model that includes the missile, the launching tube, and the launching support of an anti-tank missile weapon system is established. A corresponding computer program can be used to perform the analytical computation of the vibration of the infrared light axis during the launching process , the initial disturbance of the missile, and the random distribution of the missile during the uncontrolled flight stage. As a result of the above mentional analysis, probability of the missile to be launched into the controlable zone and the stability of the support can be estimated. the model and computer program provided in this paper are applicable to the launching dynamics analysis of similar anci-tank missile systems with different launching methods and modes of control.

A Hybrid Simulation System for the Antijamming Characteristics of Radio Proximity Fuzes

Du Hanqing,Li guanfa

1993, 14(2):  27-32.  doi:10.3969/j.issn.1000-1093.1993.02.005

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Presented in this paper is a hybrid simulation system for the antijamming characteristics of radio proximity fuzes. The architecture of the system and key techniques such as the mathematical models of the main parts and the system software design are discussed in detail. The system can be used in the field test simulation of ra- dio proximity fuzes for projectiles, rockets, bombs, and mortar shells. The system in- cluds both physical and mathematical models. The jammer and fuzes under test are physical models, while the antenna patterns of the jammer and fuzes > the trajectory, the space geometric disposal of ECCM field tests are in their mathematical models. To simulate the process of reconnaissance and frequency guidance，a subsystem is made up of a searching receiver and the jammer, microcomputer and the special interfaces. Using the system , the process of field test and the data concerned such as the space coordinate of burst can be displayed, copied and stored.

Method of Power Spectrum Density Analysis for Random Fatigue Life Prpbability and its Applications

Yao Changren, Wang Lianping, Tang GuoLiang

1993, 14(2):  33-38.  doi:10.3969/j.issn.1000-1093.1993.02.006

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Formulas giving the relationship between the cross P. S. D of two static random processes and the P. S. D of their derived processes are derived , and the mathematical model of radom fatigue life probability under the conditions of plane stresses is established, A computer program for this model is developed and its applications in the design of heavy trucked vehicles discussed.

Multiple Knowledge Representation and Diagnostic Strategy in an Expert System for Fault Diagnosis

He Boxiong, Zhong Lianjiong, Fan Yaohua, Hu Defa

1993, 14(2):  39-45.  doi:10.3969/j.issn.1000-1093.1993.02.007

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Multiple knowledge representation and strategy of trouble shooting is a key problem in building up an expert system for fault diagnosis. A " synthetic frame system" is described in this paper to represent various types of knowledge and their systematic relations in the diagnostic process. Also a new concept — " indepandent structure",with plausible search strategy, is proposed to solve the problem of multiple trouble shooting in complex systems.

An Expert system for the Planning of Polishing Processes

Ma Detong,He Boxiong, Li Fuyuan

1993, 14(2):  46-52.  doi:10.3969/j.issn.1000-1093.1993.02.008

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This paper presents the principles, structure and unique features of a gene-rative process-planning expert system-CONSULT which is developed for a multifunc-tional polisher—DFM-1. Development of such a system opens up a new domain of theapplication of CAPP and expert system technologies. The basic principles of the systemand the methodology of development, such as applications of the “planning” techniques in AI to generate process routines and employing the production system to manipulate process numbers and sequences ， are appliable also to CAPP systems for machining and assembly processes in general.

Shakedown Analysis a Thick-Walled Cylindrical Tube under the Two-Linear Mixed-Hardening Model

Zhang Guozheng,Feng Xiqiao,Liu Xinsheng

1993, 14(2):  53-58.  doi:10.3969/j.issn.1000-1093.1993.02.009

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In this paper, the yielding and hardening rules of gun-steel is first investigated through experiments. After being appropriately simplified， a two-linear mixed-hardening model is obtained. Then under the model, the shakedown of a thick- walled cylindrical tube subjected to internal pressure is analyzed. A method of defining the autofrettage of a thick-walkd cylindrical tube is given from the viewpoint of shake- down.

An Investigation on the Directions of Magnetization of Permanent-Magnet Bearings

Tan Qingchang, Meng Huiqin, Xiu Shichao,Pen Lüzhong

1993, 14(2):  59-63.  doi:10.3969/j.issn.1000-1093.1993.02.010

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In this paper, directions of magnetization of permanent-magnet bearings are investigated applying the theory of equivalent magnetic charge. It is proved that the choice between radial magnetization or axial magnetization does not have any effect on the bearing force and stiffness of magnetic bearings, if the geometric and magnetic parameters of the magnetic bearings are kept the same. This will simplify both the theoretical investigations and the processing during fabrication of magnetic bearings.

Experimental Technique and Analysis

Hard-Wired Measurement Technique of Multiple Mechanical Parameters

Zhou Tiansheng, Chen Xiang, Chen Qingsheng

1993, 14(2):  64-68.  doi:10.3969/j.issn.1000-1093.1993.02.011

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A multiplicity of mechanical parameters involved in an in-bore shock environment including the chamber pressure, acceleration, impact and strain were measured and processed simultaneously with the help of hard-wired technique in conjunction with a microcomputer system. In this paper, the equipment and deployment of the instruments for the experiments are discussed. Four major classes of the test-systein are involved , viz. , the launch system ； sensing devices for the acceleration, chamber pres- sure，impact and strain; data acqusition， recording and analysis system ； as well as the receiving system. Signal separation were completed for the measured force and strain signals, and the strain errors were calibrated.

A Method of Moire Deflectometry Used for the Visualization of Real Transient Flow Fields

He Anzhi, Yan Dapeng, Wang Hailin, Miao Pengcheng, Yang Zuqing

1993, 14(2):  69-73.  doi:10.3969/j.issn.1000-1093.1993.02.012

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In this paper, a method of moire deflectometry is presented，which is used for the visualization of real transient flow fields. Its merits are ： large-aperature, high sensitivity and elimination of system errors. It can be used to measure and visualize a real transient flow field. By means of this method, the moire deflectograms of near- field structures from real rocket exhaust, free jet and jet impingement fields wera obtained ，and the multidirectional moire deflectograms of asymmetric flow field in hypersonic shock tunnels were obtained also。

Research Notes

A Study on the Trajectory of Secondary Fuze (for Initiation of the Fillermist) in a Fuel-Air Explosive Munition

Li Denho

1993, 14(2):  74-77.  doi:10.3969/j.issn.1000-1093.1993.02.013

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A high-speed camera is used to record the process of dispersion of FAE. mist and the trajectory of projection of Secondary Fuze in a FAE. bomblet. Through data processing by image analyzer and emulation of the trajectory of projection with a computer，the following items have respectively been obtained, viz. ： process of dispersion of the FAE. mist and the optimum time of its initiation, velocity and angle of projection ，time lag and time of flight of fuza to reach its optimum point of explosion in the process of projection. The methed of investigation and data obtained are valuable references in the performance design of bomblet systems (Secondary Fuze iaciuded).

A Study on the Geometry and Electronic Structure of DDNP

Tang Zehua,Xiao Heming,Li Yongfu,Wang Daxi

1993, 14(2):  78-83.  doi:10.3969/j.issn.1000-1093.1993.02.014

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The equilibrium geometries and electronic structures of DDNP in its two structural forms and its related compounds have been optimized and calculated using the MNDO-SCF-MO method in quantum chemistry. The calculation results show that, with the cyclic azoxy configuration of DDNP，the atoms in the benzene ring and penta- cyclic ring are essentially co-planar, and the dihedral angles between the benzene ring plane and the 2- and 4-nitro group planes are 75. 2°and 78. 6°, respectively. The total molecular energies obtained for the “cyclic form” and the “quinoid form” are —3224. 5723 eV and 一 3224. 3726 eV respectively. Thus the former is presumably more stable than the latter. From the associative analysis and comparison of the geometric parameters and from the net charges on the atoms，as well as the observed 13C NMR spectra of DDNP and its related compounds > it can be concluded that the “cyclic azoxy form” is a rather suitable description for the molecular structure of DDNP. There is the larger dihedral angle between benzene ring and nitro group，which is the common experimental phenomenon and has been clarified with the electronic theory in this paper.

Some Problems in the Implantation of Structure Analysis Program SAP 6 in Microcomputers

Ren Xiaohe,Liu Xiaoming

1993, 14(2):  84-87.  doi:10.3969/j.issn.1000-1093.1993.02.015

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This paper discusses some problems encountered in the implantation of the SAP6 system in micro computers and puts forward the measures taken in their solution. The resulting system, SAP6/AT , or Structure Analysis Program in Micro computer ，has been in successful operation for years.

A Single Chip Microeomputer1 Controlled Image-Stabilizing System

Zhao Yuejin,Lian Tongshu,Yu Xiaomei

1993, 14(2):  88-92.  doi:10.3969/j.issn.1000-1093.1993.02.016

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In this paper, a new method for image stabilization with a three-axis image-stabilizing reflecting prism assembly is presented，and the principle of image stabilization in this prism assembly，formula for image stabilization and working formula with an approximation up to the third power are given in detial. In this image-stabilizing system，a single chip microcomputer is used to calculate values of compensating angles and thus to control the prism assembly. Two gyroscopes act as sensors from which information of angular perturbation is obtained, three stepping motors drive the prism assembly to compensate for the movement of image produced by angular perturbation. The image-stabilizing device so established is a multifold system which involves optics, mechanics, electronics and computer.

An Experimental Study on the Process of Mirror Finishing of Engineering Ceramics

Yu siyuan,Zhao Wankang,Jiang Peilan,Chen Xirang

1993, 14(2):  93-96.  doi:10.3969/j.issn.1000-1093.1993.02.017

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This paper describes the process of mirror finishing of engineering ceramics. On the basis of a study on the mechanism for the material removal of ceramics and the conditions affecting transformation of phases the mirror finishing of a ceramic cylindrical surface have been achieved successfully, following two optimum processing schemes as proposed. The results have been applied to the production processing of ceramic engine components.