1997 Vol.10(3)

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LASER SHOCK PROCESSING EXTENDS FATIGUE LIFE OF 2024T62
1997, 11(3).
[Abstract](2427) [PDF 123KB](89)
Abstract:
A new technology—laser shock processing (LSP) for improving the mechanical properties of metals, expecially fatigue life, is presented. The mechanism of stress wave generated by laser shocking is described, and the stress wave is measured with PVDF transducer. A high-power density, neodymiumdescribed, and the stress wave is measured with PVDF transducer. A high-power density, neodymiumglass laser was used for shocking aluminum alloy, the fatigue life of aluminum alloy was increased greatly. With 95% confidence, the fatigue life of LSP specimens is 5.4 to 14.5 times longer than the unshocked specimens.
STABILITY ANALYSIS OF FLUID FLOW IN JOURNAL BEARING
1997, 11(3).
[Abstract](2417) [PDF 142KB](93)
Abstract:
The finite difference method is applied to solve the complete 3-dimenisional Navier-Stokes equations; The critical Taylor numbers for onset of Taylor vortices in flow between the finite length eccentric rotating cylinders are calculated for various eccentricity, different clearence ratios and different lengthdiameter ratios. Results show that the critical Taylor number varies with the eccentricity, clearence ratios and length-diameter ratios, amd the critical Taylor number incerases with the increasing of eccentricity and clearence ratio, but decreases with the length-diameter ratio increasing.
PROJECTION OF ARBITRARY POINT TO PARAMETRIC BEZIER SURFACE AND ITS APPLICATION IN COMPLEX SURFACE NC MEASURING ANALYSIS
1997, 11(3).
[Abstract](2335) [PDF 171KB](89)
Abstract:
According to the characteristics of the triangular Bezier surface, an algorithm for solving the projection problem of 3D point to surface is given. This paves the way for complex surface NC measuring geometric modeling and computer simulation of sheet metal forming process.
QUALITY SYSTEM AND IMPLEMENTATION IN CIM ENVIRONMENT
1997, 11(3).
[Abstract](2300) [PDF 318KB](146)
Abstract:
A quality system ang undementation methodology in CIM environment are addressed. The quality system is one of the subsystems in CIMS which generally includes management information subsystem, engineering information subsystem, production information subsystem, quality information subsystem, and database and network support subsystem. A model of the quality system and its detailed functions are introduced. The implementing methodology and strategy of the quality system in the CIMS applied factory of China are expounded. The encountered problems which occur in the process of implementation are analyzed, and the methods used to resolve these problems are described.
NEW APPROACH FOR SOLVING RESTRICTED TORSION PROBLEMS
1997, 11(3).
[Abstract](2127) [PDF 121KB](18)
Abstract:
The reciprocal theorem method (RTM) is presented. It is a new analytical approach for solving the problems of plates and shells. It is extended to solving the restricted torsions of long bars with narrow rectangular cross section. The method is a contribution to the field of torsion research. Analysis and calculation show that the method is simple, general and effective for solving torsion problem.
PREVENTIVE MAINTENANCE MANAGEMENT
1997, 11(3).
[Abstract](2095) [PDF 298KB](107)
Abstract:
The management decision as to whether or not to introduce condition monitoring based maintenance system is reviewed. The economics of using condition based maintenance compared to other maintenance systems are investigated. Faults detection based on objective condition monitoring techniques coupled with faults that can not be detected at a sufficiently early stage by regular inspection methods are presented. An efficient method to execute planned maintenance tasks, based on the maintenance cycle criterion is described.
RESEARCH ACHIEVEMENTS ON ADVANCED NDT
1997, 11(3).
[Abstract](2125) [PDF 239KB](136)
Abstract:
Some study progresses on advanced non-destructive test (NDT) methodology and technology are presented. The signal processing and feature analysis of NDT, ultrasonic digital imaging and image processing, defect patterm recognition, NDT visualization and computer vision utilization in NDT, and development of mechatronical application systems and software for NDT are discussed.
RESEARCH ON OPTIMUM COMBUSTION CHAMBER CONSTRUCTION OF AUTOMOTIVE DIRECT INJECTION DIESEL ENGINE
1997, 11(3).
[Abstract](2157) [PDF 163KB](101)
Abstract:
The effects of the construction and shape of combustion chamber of the automotive D.I. Diesel engine on the movement of the air flow in cylinder are analyzed. Three new type of combustion chambers of the small-sized D.I. Diesel engine, quadrangle-shaped, petal-shaped and quadrangle-shaped are designed. The fluid states of the combustion chamber walls are tested by the oil film method, a simple fluid visualization technique. It is confirmed from the engine performance tests, that the quadrangle-shaped combustion chamber has a satisfactory effect on the improvement of combustion characteristics and reduction in fuel consumption and density os exhaust of the small-sized D.I. Diesel engine.
RESEARCH ON MULTI-FUNCTION INTELLIGENT IDENTIFICATION AND MONITORING SYSTEM
1997, 11(3).
[Abstract](2151) [PDF 168KB](82)
Abstract:
The multi-funtion intelligent identification and monitoring system (MIMS) is studied, and its original design ideas and the newest achievements are introduced. In MIMS, two high performance single chip micro-computers are adopted as the master controllers. The whole structure of dual MPUs parallel processing and dual ADC chips' united working are designed, and bus contradiction between the two MPUs is overcome with special designed circuit. Using the LSI circuits MIIMS integrates the charge amplifiers, the voltage amplifiers under automatic gain control, the programmable anti-blending filters, the A/D converters, the large capacity data storage, the dot array LCD and communication ports into one complete identification and nonitoring system. In the preamplifier circuit, charge amplifiers or voltage amplifiers, filters, track/hold amplifiers and A/D converters are all operated parallelly.
CORRELATION TESTING METHOD FOR DETERMINING DISTRIBUTION OF MEASUREMENT DATA
1997, 11(3).
[Abstract](2151) [PDF 190KB](96)
Abstract:
A new method to test whether the measurement data belonging to the normal distribution or not has been proposed by analyzing correaltion coefficients, the BASIC program has been passed in IBM computer. Because the statistic analysis of correlation coefficient is used, this method has more accurate, simpler and quicker advantages than traditional normal probability paper method. Correlation coefficients and the maximum correlation coefficient are given in varied groups of data by the program so that the test results are more reliable.
THEORETICAL AND EXPERIMENTAL STUDY ON MAGNETIC FLUID SEALING OF SERRATED FORM
1997, 11(3).
[Abstract](2248) [PDF 209KB](157)
Abstract:
The magnetic field distribution of ferrofluid rectangle sealing serration is analysed using Christoffel-Schwarz change and using a tiny-Tesla meter. The maximum magnetic field intensity of the sealing gap is measured. The method of the theortical analysis is mentioned to justify whether the practical tooth shape is good ornot, the correctness of the method is verified with experiment.
OPTIMAL CONTROL PRINCIPLE OF PROFILE ERRORS FOR MACHINING OF CYLINDER CAM
1997, 11(3).
[Abstract](2130) [PDF 216KB](92)
Abstract:
In order to minimize the normal errors of the profile of the cylinder cam, that are brought in by tools' radial errors in the machining process, a new machining method, optimal control method, is intoduced. Taken the cylinder cam with rectilinear translating and conical roller follower as an example, the normal errors of the cam profile arising from the optimal control machining process is discussed by using spatial meshing theory, and a simple and concise approximate formula to calculate normal errors is given. The comparison between the normal errors, arising from the optimal control machining process and conventional two-axes coordinated machinng process, respectively, shows the optimal cintrol method is of the great application value.
STUDY ON OPTIMAL INITIAL WORK ROLL PROFILE FOR COLD STRIP MILL
1997, 11(3).
[Abstract](2130) [PDF 167KB](143)
Abstract:
The model of predicting distributions of strip thickness at the exit and tension stresses is established by considering metal lateral flow, a new kind of method of calculating loaded roll gap in relation to target stress is proposed. Objective function is the minimization of the squariance of loaded roll gap deviation used for the first time to optimize initial work roll profile.
ON SIMILITUDE OF CROSS-FLOW FAN IN DYNAMIC PERFORMANCE AND NOISE CHARACTER
1997, 11(3).
[Abstract](2133) [PDF 234KB](199)
Abstract:
The similitude of a cross-flow fan is investigated by testing two fans which are different in size but similar in geometry. The results showed: There exists a critical Reynolds number whose value increases as the fan size gets larger. Above the critical Reynolds number, the similitude is tenable to both aerodynamic and noise characters. The fan size and the clearance between the impeller and the tongue has effect on similitude of cross-flow fan.