Table of Content

30 June 2003, Volume 24 Issue 2

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Paper

A Study on a Temperature Correction Equation for Pressure-Measuring Copper Cylinders

1:Kong Deren, Zhu Mingwu, ZHang Shuning,Li Yongxin;2:Pu Jian

2003, 24(2):  145-148.  doi:10.3969/j.issn.1000-1093.2003.02.001

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When pressure-measuring copper cylinders are used to measure dynamic pressures, variation of working environment temperature will often cause measuring error. To find out rules governing the temper?ature errors, experiments of dynamic calibration under high low and normal temperatures for three batches of ￠3. 5mmX 8.75mm copper cylinders have been carried out. According to the experimental data, the law of variation of pressure-measuring error was analyzed. The meaning of deriving a unitary temperature cor?rection equation for pressure-measuring copper cylinders was clarified. Means of forming the unitary tem?perature correction equation was discussed, and the correction equation was derived. The feasibility of this equation has been tested and its result was found satisfactory.

A Study on the Distribution of Length and Velocity of the Plasma Armature Arc in the Railgun Based on the B-Dot Magnetic-Probe Measuring Computer System

Qin Shihong, Liu Kefu, Pan Yuan

2003, 24(2):  149-152.  doi:10.3969/j.issn.1000-1093.2003.02.002

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Based on the B-dot magnetic-probe measuring computer system, the three measuring mathe?matical modes for the distribution oi length and velocity of plasma armature arc in the railgun bore were es?tablished, and some conclusions deduced from the measuring mathematical mode were put forward. The di?agnostic computer system for measuring the distribution of length and velocity of plasma armature arc in the railgun bore was developed. Results of experimental study were given.

Application of Wavelet Transform in Radio Fuse

1:Luo Qiang, Yang Wanhai;2:Ren Qingli

2003, 24(2):  153-156.  doi:10.3969/j.issn.1000-1093.2003.02.003

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This paper analyses radio fuse signals using the wavelets as the mathematical microscope which has the special function of singularity signals. The wavelet transform maximum is usea m order to cancel noises in the fuse signal and improve the precision of the fuse machine. The stochastic variable measure of the pulse breadth emitted by the radio fuse machine is used in order to distinguish the reality of the echo. Ihe reality of the ooject is identified according to the size of the echo energy. The maximum coordinate of different kinds of scale is used replacing tlie whole processing of radio fuse recording. So, compression of data is attained. These data include the main information of radio fuse. The idea is practicable as can be seen from the results of the experiments.

Model for Virtual Bomb Explosion Based on Half-Edge Data Structure

Zhang Zhengjun, Liu Boying, Wu Huizhong

2003, 24(2):  157-161.  doi:10.3969/j.issn.1000-1093.2003.02.004

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Simulating the generation and motion of fragments of a bomb's explosion is the key to authen?ticity and lethality in the simulation of the explosion effect. Simulating the generation of fragments is a dif?ficulty. The traditional method to simulate an explosion is based on particle system with texture paste draw?ing. These methoas ignore the mechanical principles and the related characteristics of fragments generation and motion in real explosion. A data structure was advanced that is suitable for the simulation of bomb ex?plosion stochastic half-edge data structure with motion characteristics. According to the relational me?chanical characteristics, namely, stress field of the bomb in explosion, three models were constructed for the three phases during an explosion, namely： expanding model of the bomb body, bursting model of the bomb body and motion model of the fragments. The frame of the structure of the three models and an algo- rithm for the whole process of the bomb explosion were given.

Integrating Factors and Conservation Theorem for Raitzin's Canonical Equations of Motion of Nonholonomic Nonconservative Dynamical Systems

1:Qiao Yongfen;2:Zhang Yaoliang, Han Guangcai

2003, 24(2):  162-166.  doi:10.3969/j.issn.1000-1093.2003.02.005

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A general approach to the construction of laws of conservation for nonholonomic nonconserva?tive dynamical systems was presented. Definition of integrating factors was first given. Necessary condi?tions for the existence of conserved quantities were studied in detail, and the conservation theorem and its inverse for Raitzin，s canonical equations of motion of nonholonomic nonconservative dynamical systems were then established, rmally, an example was given to illustrate the application of the result.

Spin Detonation of TNT-DINA and DNT-PETN Cast Charges

1:Zhou Lin;2:Kozak G D

2003, 24(2):  167-171.  doi:10.3969/j.issn.1000-1093.2003.02.006

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Spin detonation of cast charges TNT-DINA and DNT-PETN was studied. Detonation param?eters of the systems are capable of propagation in the form of spin-pulsating detonation at low frequencies. All such systems appear to have a detonation velocity DJ of 7. 3 ?7. 4 km/s and practically the same explo?sion heat Qv=(5.40±0.01) MJ/kg. The calculated velocity and pressure (PJ) of detonation vs. content of sensitizer were analyzed and shock temperatures were calculated by means of the SW computer code. A pressure (P3) and a temperature (T3) in the peripheral zone where damping and reinitiation of detonation take place were estimated. The PJ values for TNT-RDX mixtures are higher than those for TNT-DINA blends with the same content of sensitizer RDX or DINA. Accordingly the temperature T3 for the former system is 60?100 K higher than that for the latter. Experimental data are in good agreement with calculat?ed results.

Structural Design and Time Analysis of Synchronous Explosive Circuit in Rigid Eccentric Circumferential Lines

Wen Yuquan, Jiao Qingjie, Lu Bin

2003, 24(2):  172-175.  doi:10.3969/j.issn.1000-1093.2003.02.007

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Structural characters of rigid synchronous explosive circuits with eccentric circumference were studied. The method of symmetry was used in the structural design of the explosive circuit. Synchroniza?tion of multiple point detonation wave output was analyzed through error analysis. General expression for the error of synchronization of multiple point detonation output was obtained. Technical measures for im?proved synchronization were also proposed. These results lay a foundation for the parameter design and CAD of explosive circuit.

Data Processing in the Measurement of Large Curved Surfaces

1：Yang Thiwen, Di Xu,Jin Sukun;2:Wang Jinjiang

2003, 24(2):  176-179.  doi:10.3969/j.issn.1000-1093.2003.02.008

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Method of acquiring data in the measurement of curved surface and the method of evaluating it are introduced in tms paper. Common methods of data processing and their shortcomings were then ana?lyzed. Two improved methods were further given. It is necessary and feasible to deal with the measuring data subsequently as shown by experiments.

Computer Simulation of Digital Projections of Typical Objects Based on Computed Laminography Reconstruction

Yang Min. Lu Hongnian. Zhang Li

2003, 24(2):  180-183.  doi:10.3969/j.issn.1000-1093.2003.02.009

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In order to execute non-destructive testing for shell-like objects, a new scanning method has been introduced. X-rays irradiate on the surface of the reconstructed object along an oblique direction, through special reconstruction algorithms, cross-sections of the object can be obtained slice by slice. In practical application, however, the projection data are polluted by some factors such as noise, motion er?rors, and so on. So it is difficult to analyze the reconstruction algorithm qualitatively. In this paper, a com?puter simulation algorithm of digital projections for typical objects based on the scanning method was pro?posed ,and the results of simulation were given.

A Combined Source-Channel Coding of Fractal Image Compression

1：Luo Weixiong；2：Yang Shouyi

2003, 24(2):  184-187.  doi:10.3969/j.issn.1000-1093.2003.02.010

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Fractal image compression is a relatively recent technique based on the representation of an im?age by a contractive transform on the space of images, for which the fixed point is close to the original im?age. There are several different parts of data in a fractal image compression. Each part is different in its sensitivity to the communication channel noise. In this paper, the different sensitivities of each part of frac?tal image compression data to the communication channel noise are analyzed first. Based on it, is proposed a combined source-channel coding of fractal image compression. Simulation results show that by using this combined source-channel coding the sensitivity of fractal image compression data to the communication channel noise is reduced and the quality of the decompressed image greatly improved.

Processing of Conical Scan Step Frequency Radar Signal

Wu Qiongzhi, Long Teng, Wang Fei

2003, 24(2):  188-192.  doi:10.3969/j.issn.1000-1093.2003.02.011

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The form of conical scan, step frequency radar waveform was first given, and the interaction of conical scan and stepfrequency was analyzed based on the given expressions. The conical scan, step fre?quency radar waveform can get the angular information as well as the range information of range closed tar?gets. The close coupling processing method was developed. Some undesirable factors such as noise and mo?tion were analyzed. Ine close coupling processing method has been implemented in a real-time radar signal processing system. Results of both computer simulations and practical experiments have proved that this al?gorithm is effective.

Higher Mode Characteristics and Impedance Matching Problem of Ridged Waveguides

1:Zhang Jianghua, Li Fuli;2:Du Zicheng, Lü Ensheng

2003, 24(2):  193-198.  doi:10.3969/j.issn.1000-1093.2003.02.012

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Travelling wave expansion method (TWEM) was adopted to calculate the existing modes in naged waveguide phase shifters and their cut off wavelengths. Though it was difficult to maintain single mode transmission in ridged waveguides，the coupling between base mode and higher modes may be ig?nored. A novel equivalent impedance of waveguides was obtained through comparison with plane wave, which is more suitable for matching problem than the conventional wave impedance for TE mode. In this way the efficiency of design was improved.

Novel Algorithms to Improve the Precision of Tracking for IR/MMW Combined Seeker Based on Data Fusion

Cui Zhishe, Zeng Tao, Long Teng

2003, 24(2):  199-203.  doi:10.3969/j.issn.1000-1093.2003.02.013

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Guidance precision is a significant performance index for homing guidance weapons. The seek?er tracking precision，wmch is determined by accuracy of measurement oi the error measurement compo?nent, is one of the major factors that influence the guidance precision. Based on IR/MMW dual-mode, common aperture structure and information fusion technology，two approaches are provided to improve the LOS(Line of sight) angular rate estimated precision and finally enhance the weapons performance. Simula?tion results show that the approaches are effective.

A Study on the Movement of Rocket under Down-Wash Flow of a Helicopter’s Rotor

Zhou Kedong, Li Ziyong, He Lei, Le Guigao

2003, 24(2):  204-208.  doi:10.3969/j.issn.1000-1093.2003.02.014

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Forces and moments exerted on rockets under the down-wash flow of a helicopter，s rotor were analyzed in detail. The corresponding formulae for the aforementioned forces and moments were deduced. Based on above-mentioned formulae the mathematical and physical model of a rocket under helicopter rotor， s down-wash flow was established. With numerical simulation, the regularities of a rocket under helicopter rotor’s down-wash flow and the effects of launching parameters upon the rocket movement were obtained. These results provide a basis for further studies on rocket ballistic control and modification and were thus of reference value.

Mathematical Model for an Accumulator and Its Gas Generator

1：Wang Shushan；2：Gong Ping

2003, 24(2):  209-211.  doi:10.3969/j.issn.1000-1093.2003.02.015

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Aimed at the piston-accumulator unit for use as the control system on torpedoes, a mathemati?cal model for the accumulator and its gas generator was established，and its method of numerical calculation was given. On the basis of this model, relationships between gas pressure and hydraulic pressure to time for the accumulator and its gas generator of the certain structure and charge were obtained. By comparing the calculated results to the experimental data, the value of this mathematical model in the structural optimiza?tion of accumulators and in the design oi its gas generators is apparently visible.

Evaluation of the Combat Effectiveness of a Laser Guidance Bomb

1:Fang Yufeng;2:Zhang An

2003, 24(2):  212-215.  doi:10.3969/j.issn.1000-1093.2003.02.016

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This paper studies the evaluation model for the combat effectiveness of a certain type of laser guidance bomb. A mathematical model with six freedoms of movement is established to describe a single aircraft attacking a single target. Using the Monte Carlo method, effectiveness indices of aiming precision and kill probability are obtained. Several factors influencing the combat effectiveness of laser guidance bomb are analyzed.

Reliability Design Method of Fatigue Strength under Steady Variable Stress

1LChen Fengxi;2:Li Liangqiao, Liu Ying, Ji Guangzhen

2003, 24(2):  216-218.  doi:10.3969/j.issn.1000-1093.2003.02.017

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In the fatigue strength design of mechanical parts under steady variable stress, checking on the degree of safety in dangerous sections of parts and evaluation on the reliability for the purpose of reach?ing design requirements must always be kept in mind. It is difficult to evaluate the reliability of dangerous sections, because the allowable ultimate stress changes with increased working stress. In this paper, some factors affecting the ultimate stress and life coefficient were studied, such as stress concentration, size and surface situation. A reliability design method of fatigue strength was obtained when the stress cycle charac?teristic is constant, and the working point is within the fatigue zone and. the plastic zone.

A Study on the Performance of a Composite Armour Plate of Ceramic/GRFP/Steel

Du Zhonghua, Zhao Guozhi, Yang Yulin

2003, 24(2):  219-221.  doi:10.3969/j.issn.1000-1093.2003.02.018

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Based on the performance and characteristics of ceramic composite armors is established an analytic model for a long rod projectiles penetrating normally a finite thick ceramic/GRFP/steel plate form?ing a composite armour, suitable for long rod projectiles hitting at a velocity from 1000m/s to 2200m/s. With this model is calculated the formula of estimating the ballistic performance V50 of such kind of com?posite amour. The formula is verified through experimentation using simulation projectiles, reaching satis?factory conclusions.

A Study on the Method of Evaluation in the Maintainability Design of Weapon Systems

Feng Bing, Zhang Jingping

2003, 24(2):  222-225.  doi:10.3969/j.issn.1000-1093.2003.02.019

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In the phase of weapon design,proceeded qualitatively from factors of maintainability design, and starting from the interaction of factors, two concepts were first put forward in the paper： attribution of maintainability design and degree of facilitation. Then, Arough the directed graph and theory of matrix, the maintainability design of weapon systems for the integrated evaluation model was discussed. Methods and processes of maintainability as an integrated evaluation were finally given.

Laser Surface Hardening of Spur Gear

Li Zhanguo, Zhang Hong, Shi Yan ,Xu Chunying

2003, 24(2):  226-229.  doi:10.3969/j.issn.1000-1093.2003.02.020

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Application of laser hardening is a newly developed technique in the surface hardening of spur gears. The three key techniques, namely gear deviation, speed changes, and assisted cooling for the laser surface hardening of spur gears were proposed. Using these techniques, a uniform hardened case along the gear flanks can be obtained easily. Test results show that deformations in laser-hardened gears was negligi?ble to influence gear precision. Ine microstructure of hardened case consists of a hardened zone, heat-af?fected zone and the base materials.

A Study on Integrated Optimal Design for a High-Precision Internal Grinder

1:Sun Qinghong, Chen Nan;2:Hu Rufu

2003, 24(2):  230-233.  doi:10.3969/j.issn.1000-1093.2003.02.021

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Dynamic optimization design is the key to improve the machining precision of machine tools. The structural deficiencies of the internal grinder was pointed out by analyzing its FE model. A method of frequency correction was proposed, by which the mold frequencies of the main parts of the internal grinder were disclosed, and increase in vibration of the internal grinder avoided when the prompting frequency of the internal grinder comes close to its nature frequency. In addition, the value of relative vibration between the cutting-tool and work piece in its first natural frequency was considered as a standard of estimation of the machining precision for internal grinders, the model-force method was applied to seek the structural weakness of the internal grinder in order to achieve dynamic optimization of the parts. The results of both methods applied in the integrated optimal design of the internal grinder show that the first stage natural fre?quency of the re-designed internal grinder is increased 17% compared with the original, the vibration mode relative displacement between the head of grinder and work piece is reduced 10%，and the response-dis- placemen,ts of the first ana second stage natural frequency in the head of the grinder is reduced 28% and 41%.

Theory and Method of Rectifying the Axial Deviation of Holes in Deep Holes Dnlling

1:Gao Benhe, Zheng Li, Li Zhizhong;2:Xiong Zhenqin Wu Xutang

2003, 24(2):  234-237.  doi:10.3969/j.issn.1000-1093.2003.02.022

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Axial deviation is an unavoidable technical problem when drilling deep holes, and its rectifica?tion is an urgent task posed before the deep-hole drilling professionals both domestic and overseas. Analyz?ing the mechanism of the axial deviation in drilling holes, the paper proposes a new theory and method to rectifying the axial deviation of holes. The key is to specify a proper rectification point and apply a station- ary force, as have been verified in drilling experiments. The proposed procedure prdvides a theoretical and practical basis for the rectification of the axial hole deviation in deep hole drilling.

Software Integration of VXI Control-Measure Platform for ETCG

Yuan Weiqun, Li Baoming, Gu Jinliang

2003, 24(2):  238-241.  doi:10.3969/j.issn.1000-1093.2003.02.023

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This paper presents a way of software integration of VXI measure-control system. The VXI system includes four kinds of VXI modules ： timing-trigger module, high speed DAQ，velocity-measuring module, and switch module. It works well under cases with ETCG propellants is characterized with many working parameters, complex working-flow and adverse conditions. It can also fulfill the SPGjS measure tasks. Two system-triggering models are described： the joint action model and the separate action model. The joint action model triggers all oi the V XI modules according to a set timing sequence needed in a single task. The two forms of system triggering enlarge the VXI measure-controi system’s functions.

Short Notes

The Calculation of Stabilizable Radius of Plants Family

Liu Shiyue, Wu Qinghe

2003, 24(2):  242-245.  doi:10.3969/j.issn.1000-1093.2003.02.024

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The optimization method is adopted to convert the calculation problem of stabilizable radius of the plant family into an optimization problem. At the same time, the method does not have any restriction to definition forms of stabilizable radius and to uncertaintily parameter constructions. Hence, the method proposed in this paper has generality.

Comprehensive Reviews

Present State and Future Outlook of the Simulation of Tracked Vehicles

Han Baokun, Li Xiaolei, Sun Fengchun

2003, 24(2):  246-249.  doi:10.3969/j.issn.1000-1093.2003.02.025

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Tracked vehicles play an important role in the military field. Due to the complicatedness of tracked vehicle and its environments of application, traditional methods of research result in high cost and long cycles of development. Modeling and simulation have become a trend in the fields of research of tracked vehicles. They have greatly pushed forward the development of tracked vehicles. Stage achievements are re?viewed and summarized in terms of riding models, pressure distribution, mobility and other models, steer?ability models etc. in this paper. Some popular softwares used in the dynamic simulation of tracked vehicles are introduced. Also directions of research in this field in the future are pointed out.

Experimental Techniques and Analysis

Telemetering for the Attitude of Projectile in Flight Based on the Principle of Solar Aspect Angle

1:Gui Yanning;2:Yang Yan

2003, 24(2):  250-252.  doi:10.3969/j.issn.1000-1093.2003.02.026

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In this paper a study is made on the telemetering system of solar aspect angle by digital mea?surement and preprocessing on board to meet the needs of measurement in the flying projectile attitude con?ventional ordnance. The principle of measurement and mathematical model of the solar aspect angle were given and a scheme of practicable digital telemetering system for the measurement was also propounded. The system has been used in practice for the test of projectiles which survive as high as 18 thousands g. The solar aspect angle data of high g projectiles in flight has been gained for the first time domestically and the mutational motion, precessional motion and spinning motion were derived from these data.

A Study on the Explosion Initiation by Electrically Exploded Conductor Driving a Small Flyer

Tan Yingxin, Zhang Jinglin ,Wang Guiji

2003, 24(2):  253-256.  doi:10.3969/j.issn.1000-1093.2003.02.027

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A new kind of explosion initiation technique is studied. Parameters of key elements in the ae- vice were analyzed. The experimental device and method of electrically exploded conductor driving the flyer were given. By this device, the initiation threshold of PETN and HNS— II have been tested.These data show that the thickness of the flyer plays an important role in the energy ot initiation.

De-Noising Methods and Its Applications in Sensing Signals Processing Noises

1:Dai Longcheng, Xuan Yimin;2:Yin Jian

2003, 24(2):  257-260.  doi:10.3969/j.issn.1000-1093.2003.02.028

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De-noising by soft-thresholding is a new signal detection method in wavelet analysis. On the basis of briefly introducing the wavelet analysis and nonlinear theory by soft-thresholding, useful informa?tion reflecting the missile’s vertical acceleration can be effectively extracted from highly noised signals. The paper also uses the soft-thresholding de-noising method to distinguish the trend of vertical velocity between normal and failure signals containing noises. The study shows the validity of the application of wavelet anal?ysis to launching systems.

A Study on a Laser Inspection Device for the Straightness of Bore

Ma Hong ,Pan Yuxue, Che Ying,Li Lan, Zhou Jianmin

2003, 24(2):  261-263.  doi:10.3969/j.issn.1000-1093.2003.02.029

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A device applying the technique oi laser collimation and photoelectric inspection for Ae inspec?tion of straightness error oi bore can be used to replace tne traditional optical inspection method and realize non-destructive automatic inspection. The working principle and scheme of implementation of the device are briefly introduced.

Research Notes

Effect of Initial Temperature of Base Bleed Grain on Its Range

Guo Xifu

2003, 24(2):  264-265.  doi:10.3969/j.issn.1000-1093.2003.02.030

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This paper has proved that base bleed grain initial temperature, which will produce fire devia?tion and make the hit probability lower, has great effect on the range in theory and experiment. In order to enhance hit probability, it has added the correction term for base bleed grain initial temperature in the fire table, and has included the effect factor of base bleed grain initial temperature in the fire control ballistic model.

Determination of Overall Structural Parameters of Small Caliber APDS

Li Xiaoli, Zhao Guozhi

2003, 24(2):  266-269.  doi:10.3969/j.issn.1000-1093.2003.02.031

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Under restrictions of launch strength and muzzle kinetic energy, the optimization of sub-cal?iber ratio, length-to-diameter ratio, and the rod mass were studied in order to satisfy the sabot mass, effi?ciency of muzzle kinetic energy, ballistic stability and the necessary velocity of limiting penetration. It pro?vides reasonable basis for the structural design of small caliber APDS.

Thermal Stability Prediction for the Melting Process of an EAK-Based Intermolecular Melt-Cast Explosive

Zhao Shengxiang, Hu Huanxing, Zhang Yian

2003, 24(2):  270-272.  doi:10.3969/j.issn.1000-1093.2003.02.032

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The critical thermal explosion temperatures of an intermolecular explosive,a mixture of EAK (eutectic of ethylenediamine dinitrate, ammonium nitrate, potassium nitrate) and RDX , was investigated experimentally. By analyzing the experimental results with Semenov、Thomas and Frank-Kamenetskii criti?cal functions，the thermal decomposition kinetic parameters were obtained ： the Arrhenius activation energy is 158.2 kj ? mol-1，and the pre-exponential factor is 1. 46 X 1O13 s-1 . According to the thermal explosion theory and based on the thermal decomposition kinetic parameters, the thermal explosion ignition hazard was predicted. As a result, it indicated that this explosive is stable and safe in the melting process of temper?atures below 130°C and size of melting kettle less than 2m.

High-Speed Acoustic Target Recognition Based on Wavelet and DSP

Tang Haifeng, Li Haojie Zhang He

2003, 24(2):  273-276.  doi:10.3969/j.issn.1000-1093.2003.02.033

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Theory of wavelet and FOBW(feature of bordering waveform) coding are used in extracting the characteristics of acoustic targets. A DSP chip, the kernel of the system, and some necessary devices were designed to accomplish high-speed target identification. The results obtained in this way appear to be satisfactory.

Research and Design of Advanced Fast Agile Frequency Synthesizer

1:Guo Dechun, Fei Yuanchun;2:Yang Wenge

2003, 24(2):  277-279.  doi:10.3969/j.issn.1000-1093.2003.02.034

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The paper presents a fast agile frequency synthesizer of low spurious, low phase noise. The scheme adopted by the synthesizer is a DDS chip(AD9852) at double frequency. The control circuit uses TMS320C31 of TI Inc. for the sake of swift frequency change and output frequency precision. The time of frequency agile is less than 200 ns, ana its phase noise is less than — 124dBc/Hz/1 kHz.

Solutions for the Firing-Equation in a Digital Collimator Working in Independent Mode

Sheng Andong, Lü Taiquan, Chen Chun ,Guo Zhi

2003, 24(2):  280-282.  doi:10.3969/j.issn.1000-1093.2003.02.035

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Based on digital collimator working in independent mode, a gyroscope simulation method is presented to solve the iirmg equation. The firing-equations are worked out with the distance given in ad?vance ,relevant angular information acquired from both the angle-sensor on artillery and object circle coordi?nates in the collimator window. Above-mentioned method is conveniently realized by the software and the shooting precision can be effectively improved. The method has been applied in an artillery weapon system. Test results in the proving ground are given.

Limitations and Countermeasures of Helicopter Upper Housing Forming Processes

Xue Kemin, Lü Yan, Xu Fuckang, Hao Nanhai

2003, 24(2):  283-285.  doi:10.3969/j.issn.1000-1093.2003.02.036

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Upper housing, a key part of helicopter, is difficult to be formed owing to its big size, com?plex geometry and high demands in requirements as to its characteristics and properties. In order to design the forming process properly, the forming process of the upper housing was investigated with the aid of physical modeling using pure lead. Isothermal forging technology and combined-die structure were adopted. The upper housing was forged successfully with the above isothermal precision forging technique. The me?chanical properties, micro and macro-structure as well as the accuracy ot the component satisfied the user’s requirements.

A Study on Low Pressure Casting Technology of Aluminum Alloy Applying Electromagnetic Pump

Dang Jingzhi, Yang Jing, Cheng Jun

2003, 24(2):  286-288.  doi:10.3969/j.issn.1000-1093.2003.02.037

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Based on principle of electromagnetic pump, the low pressure aluminum casting setup consist?ing of the electromagnetic pump and a holding furnace has been developed. Through experiments, relation-ship Detween flow capacity, lift and their factors of influence were determined. A mathematical model has been built up for controlling the low pressure casting process. Under automatic control, castings have been produced by this setup, and satisfactory result have been obtained.