西南交通大学学报

Experimental Investigation on Vibration Performance of Polyurethane Foam Plastic

TANG Yi-ke, GONG Xian-sheng, GU Qian-kun

2003, 16(5): 497-500.

[Abstract](1542)

Abstract:
An experimental device of the vibration performance of foam plastic was set up. The vibration test of a reinforced plastic material was carried out. Experimental results show that the vibration performance of this foam plastic material has relation not only to vibration amplitude but to exciting frequency. The restoring force of the foam plastic material is influenced by exciting frequency, vibration amplitude and deformation history. The foam plastic material has a nonlinear hysteretic characteristic. In vibration conditions, stiffness and damping characteristics of the foam plastic material are nonlinear. The research lays a foundation for modeling and parameters identification, dynamic design and dynamic optimization of the vibration-isolation material.

Optimum Design of Industrial Crystallizer Impeller Based on Computational Fluid Dynamics

XUE Zhao-peng, XU Yan-shen, NIU Wen-tie

2003, 16(5): 501-504.

[Abstract](1444)

Abstract:
Based on analyzing the structure of industrial crystallizer impellers, their parametric design was realized with pitch ratioh/D, blade area ratioAE/AOand draft tube-stir tank diameter ratiod/D′as the basic parameters. Based on the principle that all points in a crystallizer have the same flow rate, a general purpose CFD (computational fluid dynamics) software Fluent was used in the quantitative analysis of the flow field in a crystallizer, and the optimization parameters was obtained,i.e. h/D=1.2, AE/AO=0.7 andd/D′=0.63.

Auto-testing Technology of Compaction Degree and Its Application

DENG Xue-xin, WANG Tai-yong, REN Cheng-zu, WANG Xing-hua

2003, 16(5): 505-508.

[Abstract](1560)

Abstract:
On the basis of the present methods of compaction testing, the mechanical model of a vibrating roller-soil system was analyzed and its dynamic equation was established. The relationship between vibration acceleration and soil rigidity and soil damp was obtained by simulation. Based on the simulation result, the auto-testing principle of compaction degree was put forward,i. e. through testing the vibration acceleration of the vibrating roller, the soil compaction status can be reflected indirectly. A auto-testing system was developed and applied to a project, and the strong relativity between soil compaction degree and vibration acceleration was verified.

Dynamic Impact and Fracture Toughness of 16MnR Welded Joints

YU Qin, HUO Hong-fa, GONG Shui-li

2003, 16(5): 509-512.

[Abstract](1163)

Abstract:
The dynamic impact energies of 16MnR welded joints were determined with high speed impact test, and the influencing factors and fracture morphology were studied. The impact toughness of 16MnR welded joints decreases greatly and the joints become brittle in general with an increase in impact speed. The results suggest that more attention should be paid to the dynamic impact toughness of a welded joint when it is subjected to high speed impact loads.

Numerical Simulation of Dynamical Responses of Assembled Vessel to Explosion Impact Load

HUO Hong-fa, YU Qin, HUANG Xie-qing

2003, 16(5): 513-516.

[Abstract](1690)

Abstract:
The dynamic responses of an explosion vessel with a cylindrical shell and ellipsoidal closures were numerically simulated using ANSYS/LS-DYNA, and the results were compared with those of experiments. The study reveals that the peak pressure on the shell decreases gradually from the center of the cylindrical shell to the ellipsoidal closures with an increased acting duration. The peak attains minimum in the joints of the cylindrical shell and the ellipsoidal closures, then gradually increases again. The maximum strains of the shell decrease away from the explosion center, the minimum value appears in the joints of the cylindrical shell and the ellipsoidal closures and gradually increases, and the maximum compression stress occurs at the biggest curvature.

Optimum Design of Static and Dynamic Properties of Mechanical Structure Based on FEM

XU Yan-shen, ZHANG Xue-ling

2003, 16(5): 517-520.

[Abstract](1555)

Abstract:
On the basis of variational design technology based on FEM and its application in static and dynamic structure designs, the concepts of structural quasi-static property and variational design were stated, and as an example, the structure of a hydraulic machine was optimized using the quasi- static variational optimization design. In addition, the method of improving its dynamic properties by the dynamic optimization of element structures was proposed. Finally, the general principle and method of dynamic optimization design of mechanical structures were discussed.

Fuzzy Identification Method for Mechanical Joint Parameters Based on Transfer Function

LIUXiao-ping, PENG Zhao-yang

2003, 16(5): 521-524.

[Abstract](1499)

Abstract:
To identify the parameters of a mechanical joint precisely, a new method based on transfer function and fuzzy optimization was proposed. The theoretical formulas and numerical analysis were presented. The numerical results demonstrate that the new method overcomes the disadvantages of the least square method and is more accurate. The presented example shows that the identification error is not larger than 5.2% under the condition that the with a maximum random error is 5% in the transfer function.

Application of Time-Frequency Analysis Method to Start-up Process Analysis of High-Pressure Hydraulic Pump

TANG Yi-ke, LIANG Feng

2003, 16(5): 525-527.

[Abstract](1344)

Abstract:
The determination of time discrimination and frequency discrimination and the selection of a window function in the short-term Fourier transform(STFT) were discussed to analyze the vibrational signals from a high-pressure hydraulic pump unit. This method based on the STFT overcomes the shortcoming of the fast Fourier transform. The analysis result shows that the application of time-frequency analysis method to the start-up process analysis of centrifugal type of high-pressure hydraulic pumps can not only exactly determine the change of each individual frequency in the process, but also find out some external interfering signals to judge whether a pump is working normally or not and the reason for its fault.

New Diagnosis Method of Individual Cylinder Misfires by Phase Analysis of Crankshaft Torsional Vibration

YAN Bing, DONG Da-wei, QINPing, HUA Chun-rong

2003, 16(5): 528-530.

[Abstract](1441)

Abstract:
To diagnose misfires of an individual cylinder accurately and easily, a new method using phase angles of harmonic torsional vibrations of a crankshaft was developed according to the principle of internal combustion engine dynamics. The misfire cylinder can be detected with the new method without a requirement for any experience. The method was confirmed through simulation and experiments on a 6135ZG type diesel engine. The results show that the misfire cylinder can be determined by phase angle of 0.5 order torsional vibration displacement accurately

Phase Characteristic of Torsional Vibration of Internal Combustion Engines and Its Application

LIHui, DONG Da-wei, YAN Bing

2003, 16(5): 531-533.

[Abstract](1425)

Abstract:
The phase characteristic of simple harmonic components of torsional vibrations of internal combustion engines was studied by simulation. The calculate results of torsional vibrations influenced by the phases of simple harmonic actuating torque was analyzed. The relationship between the phase characteristic of harmonic torsional vibrations of single crankshaft and that of corresponding harmonic actuating torque was investigated. The results show that the phase of harmonic actuating torque greatly influences the calculate torsional vibrations, and the phase of actuating torque must be taken into account in calculation of torsional vibrations. It is feasible to use phase characteristic of harmonic torsional vibrations of crankshafts to diagnose the misfire of an individual cylinder.

Gear Box Performance Test Based on Threshold Relevance Degree

WANG Wei, TANG Li-wei, ZHENG Hai-qi, LUANJun-ying

2003, 16(5): 534-536.

[Abstract](1498)

Abstract:
Standard normal patterns for gear boxes were established with statistical method and by analyzing vibration signals acquired from the gear boxes with a vibration acceleration sensor. Then the threshold relevance degree between the vibration signals and the standard normal patterns was calculated. Experimental result on a wheel box shows that the calculated threshold relevance degree is a good parameter to reflect the performance of the gear box under experiment. The whole test can be conducted with the help of a computer.

Influence of Rotor System Parameters on Critical Rotation Speed for Rubbing

MAJian-min, ZHANG Wen, ZHENG Tie-sheng

2003, 16(5): 537-539.

[Abstract](960)

Abstract:
Through theoretical analysis and simulation of rubbing of Jeffcott rotor systems, the analytical formulae of the critical rotating speed for rubbing to occur between the rotor and stator was obtained. The influences of the parameters, such as damping, eccentricity and clearance, on the critical speed were discussed. When the ratio between the eccentricity and the clearance is greater than 1, the critical speed decreases with the increase in eccentricity or the decrease in clearance, and increases with the increase in damping. When it is less than 1, the critical speed increases first with the increase in the ratio, decreases after reaching the peak, and decreases with the increase in damping.

Intelligent Fault Diagnosis, Prediction and Maintenance System of Mechanical Equipment

CHEN Shan, WANG Tai-yong, WANG Guo-feng, QINXu-da

2003, 16(5): 540-543.

[Abstract](1354)

Abstract:
The software and hardware frameworks for fault diagnosis and state prediction of mechanical equipment were established, and the methods and technologies of the diagnosis and the prediction were discussed in detail. Based on the above, a system of intelligent fault diagnosis, prediction and maintenance(IFDPM) of mechanical equipment was developed. This system has been applied to the analysis of grinders in Beijing Jeep Co., Ltd., and the diagnosis result agrees with the fealty, which shows the practicability of the system.

Development of Kinematics Simulation System for CK1416 High Speed/Precision NC Lathe

WUNan-xing, SUN Qing-hong

2003, 16(5): 544-546.

[Abstract](1491)

Abstract:
Based on the principle of virtual prototype machines, the kinematics simulation system for the CK1416 type lathe was developed to provide a basis for quickly designing and optimizing lathes. A designer can not only observe the three-dimensional dynamic movements of the whole lathe in the virtual circumstance, but also forecast accurately and solve possible problems during design before the prototype is manufactured, assuring the feasibility of design scheme, shortening the period of product design and reducing the cost of production.

Prediction of Stability Limits for Regenerative Chatter System of Machine Tools

ZHAO Hong-wei, WANG Xiao-jun, YUJun-yi

2003, 16(5): 547-552.

[Abstract](1615)

Abstract:
The correlation between the cutting width limit and the rotation speed of the spindle in a regenerative chatter system was derived. A method to predict the stability limits of machine tools was proposed, and the results predicted with the method were compared with experimental data. The comparison shows that the error of the predicted minimum limit of cutting width is 32%, and that of the relevant limit of rotation speed is less than 10%.

Dynamic Characteristics of Double-Rotor System for High-Speed Spindle of Precision NC Lathe

GUO Ce, SUN Qing-hong, JIANG Shu-yun

2003, 16(5): 553-557.

[Abstract](1636)

Abstract:
The exact transfer matrix method was used to analyze the dynamic characteristics of the high-speed spindle system of a precision NC lathe. The method has the advantages of calculation simplicity, high accuracy and easy programming. The coupling stiffness of the double rotors was calculated effectively with FEM.

Development of Simulation System of NC Turning Machine

WANG Tai-yong, WANG Xiao-bin, WANG Guo-feng, LIHong-wei, ZHAO Wei, WANG Wen-jin

2003, 16(5): 558-561.

[Abstract](1891)

Abstract:
From the features of NC turning process, a workpiece decomposition expression model based on the constructed units was put forward, and Boolean subtraction was performed using this model and a tool solid model to simulate the real-time process of cutting and validate the simulation result. Based on the above and the principle of cutting force and chip generation, cutting parameters and some related parameters in geometric simulation, such as cutting depth and cutting velocity, were extracted and used in the calculation of cutting force and the simulation of chip. This NC turning machine simulation system is the integration of geometric and physical simulation.

Vibration Intensity Prediction Model for Large Rotating Machinery Based on Virtual Instrument

XUXiao-li, HAN Qiu-shi, XU Bao-jie

2003, 16(5): 562-565.

[Abstract](1589)

Abstract:
To predict the conditions of large rotating machinery, a gray prediction model was proposed, and an open and flexible prediction system based on virtual instrument (VI) was developed for easy adaptation to new users and application. This system was developed by using LabVIEW and VC++,and has been applied in industry. The results of practical verification on large pumps indicate that the technology presented is capable of predicting the date of a fault and reducing the times and cost of maintenance.

Remote Virtual Fault Diagnosis System of Equipment Based on COM

XIAO Luan, WANG Tai-yong, QINXu-da, WAN Shu-min, LIU Song-tang

2003, 16(5): 566-569.

[Abstract](1490)

Abstract:
To solve the problems in current remote fault diagnosis, COM, as core technology, was introduced into the remote virtual fault diagnosis system of equipment. The design and implementation approaches of thissystembased on COMwere discussed deeply so as to make it intelligent and independent. In addition, COM, DCOM and virtual testing technologiesetc.were analyzed.

Equipment Management Information System Based on Internet and Condition Monitoring

LIU Song-tang, WANG Tai-yong, XIAO Luan, LI Rui-xin

2003, 16(5): 570-573.

[Abstract](1269)

Abstract:
An equipment management information system was developed. This system is based on Internet and can be integrated with an equipment condition monitoring system. The network and database technologies used in its development were discussed in detail, and the network technology and method of acquiring information were investigated. The implementation of management idea based on condition monitoring in this system was emphasized.

New Method for Multi-resolution Analysis in Signal Processing

LIN Fu-yong, WANG Tai-yong

2003, 16(5): 574-577.

[Abstract](1609)

Abstract:
To apply finite element method in signal processing, the elements were orthogonalized based on group theory to form a series of orthogonal functions in a cyclic zone,and the orthogonal functions were applied in function approximation. The iterative relation between the coefficients of finely divided orthogonal functions and roughly divided ones in the function approximation was presented, and used in multi-resolution analysis and signal compression.

Application of Quadric Time-Frequency Distribution to Mechanical Fault Diagnosis

QIAN Shu-hua, WANG Xin-qing, LIHuan-liang

2003, 16(5): 578-580.

[Abstract](1438)

Abstract:
Quadric time-frequency distribution can reveal the characteristic of signals by means of the combination of the features of time and frequency domains. A new time-frequency distribution was proposed by designing a new kernel function with a narrow time domain and a wide frequency domain and concentration of energy in low frequencies. The new time-frequency distribution has great power in analyzing various complex signals. An example is presented to show that the distribution has a high resolution in both time and frequency domains, and can reveal cyclic weak pulse components merged in the strong background of resonance noises and harmonic components. Such a distribution is a power tool for the diagnosis of mechanical faults.

Mathematical Model Analysis of False Alarm in Mechatronics Built-in Test Systems

YANG Guang, QIUJing, WENXi-sen, LIU Guan-jun

2003, 16(5): 581-583.

[Abstract](1481)

Abstract:
Based on the mechanism of the false alarm and built-in test (BIT) system information treating process, a model was established for calculating false alarm rate (FAR). Based on the Bayes probability, an analysis model for FAR in general BIT systems was established. For decreasing FAR, an improved model for BIT systems with embedded abnormal data detecting and renewing functions was proposed, and the effectiveness of the proposed model was proved. The factors affecting FAR were analyzed systematically, revealing that the main characteristic parameters include the FAR on diagnosis layer and the missed alarm rate and fault rate on sensor layer.

Data Exchange Between CAD and Finite Element Models in Modular Design

ZHANG Xue-ling, XU Yan-shen

2003, 16(5): 584-587.

[Abstract](1379)

Abstract:
A modular design frame based on the static and dynamic analyses of structures by the finite element method (FEM) was put forward. To overcome the difficulty in data exchange between a CAD model and an FE model in a modular design system, three approaches,i.e.simple translation approach, standard parts library approach and central database approach, were proposed for different applications. The concrete measure of data transmission using the central database approach was discussed particularly.

Research on Error Analysis and Processing Methods for Thread Solid

WANG Ling-yun, HE Yan-li

2003, 16(5): 588-591.

[Abstract](1244)

Abstract:
The geometric model of a spiral was established. The reasons for the geometric error of thread solid and the methods of reducing the error were discussed. The above theoretic analysis was verified by using the two practical methods of thread design provided by the dynamic link library of the C-Hooks in Mastercam 8, and satisfactory results were obtained.

Development of Digital Video Monitoring System for Steel-Making Process

XIE Zhi-jiang, HAN Zhi-hua, XIAO Yi

2003, 16(5): 592-595.

[Abstract](1409)

Abstract:
From the characteristic of converter steel-making processes, a digital video monitoring system for steel-making plants was developed. The key technologies of this system, such as multicast technology, communication and synchronization technologies of multithreads were discussed. In this system, the real-time processing of flame images gathered is carried out for real- time control of the steel-making process. Its application result shows that the system meets the needs of steel-making process monitoring.

Design of High Quality Anti-aliasing Filter

PENG Yong-sheng, WANG Tai-yong, FAN Sheng-bo, WUZhen-yong, WANG Shuang-li

2003, 16(5): 596-601.

[Abstract](1680)

Abstract:
The analysis and calculation show that low-pass Butterworth filters, Bessel filters and 3- dB Chebyshev filters have respectively a phase delay of -90°, -74.2°and -114.4°at the cutoff frequency, while their stopband attenuation is respectively -40, -35.9 and -43 dB/oct, where the input frequency is ten times the cutoff frequency. For frequency above 40 kHz, low-pass filters with an MFB(multiple-feedback) structure has better performance than those with an S-K(Sallen- Key) structure. As a result, the design of anti-aliasing filters can be optimized.

Experimental Research of Intelligent Active-Member for Self-adaptive Deployable Structures

YAN Shao-ze, XIAO Li-ying, ZHENG Kai, WU De-long

2003, 16(5): 602-605.

[Abstract](1402)

Abstract:
A new type of intelligent active-member with the functions of sensation and actuation was designed and manufactured for the self-adaptive control of deployable structures. The performances of displacement and force outputs of the active-member, as well as its dynamic response, were investigated experimentally, and its displacement and force gains under different frequencies of input voltage were obtained. The experimental results show that the active-member can be used for eliminating joint clearance, precise positioning and suppressing structure s vibration.

Screening Model for Drilling Fluid Shale Shaker and Computer Simulation

ZHU Wei-bing

2003, 16(5): 605-608.

[Abstract](1267)

Abstract:
Based on the basic principle of hydromechanics, the flow characteristic of drilling fluid on the screen was studied. By taking the consideration of various parameters affecting the screening effects, such as vibration and screen angle, a screening model for a drilling fluid shale shaker was established. The screening equations were solved by average energy principle and finite differential method, and the treating capacity of a shaker was calculated numerically. The comparison between the results of calculation and indoor simulation rig test shows that the screening model is of high accuracy.

Calculation of Additional Longitudinal Forces in Continuously Welded Rails on Supper-Large Bridges of High-Speed Railways

CAI Cheng-biao

2003, 16(5): 609-614.

[Abstract](1870)

Abstract:
With the track, bridge and its piers taken as an integrated system, the finite element model to analyze the additional longitudinal forces in continuously welded rails (CWR) on bridges was established. The distribution of additional longitudinal forces due to temperature and bridge flexure and the influences of braking forces and the forces due to rail breaking were studied. The results by simulation conform with the principle of CWR on bridges. A simulation program named BCWR is presented, which can be applied to the design of CWR on supper-large bridges of high-speed railways.

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2003 Vol. 16, No. 5