Papers by Author: Yan Wang

Abstract: B₄C-CeB₆ porous composites are prepared by hot pressed sintering between 1900°C and 2000°C, and mechanical properties and phase composition of B₄C-CeB₆ porous composites were tested. The results show that the porous rate of B₄C-CeB₆ porous composites ranges between 30%-48% at sintering temperate 1900°C-2000°C. Porous rate of B₄C-CeB₆ porous composites is decreased with temperature be increased. Flexibility strength of B₄C-CeB₆ porous composites is greatly improved compared with that of monolithic porous boron carbide. B₄C react with CeO₂ to completely form CeB₆ in porous composites.

Abstract: For long time span, the impact of many factors, uncertainties and other characteristics of mid-long term load forecasting, as well as the over-estimation of interval arithmetic, a mid-long term load forecasting method based on interval Taylor model algorithm was presented. In order to avoid misjudgment of the relationship between variables, reducing over-estimation problem, a global variable named Taylor model ID was presented to identify the independent variables and the dependent variable. The same independent variables construct the interval Taylor model only once. Use Maclaurin formula to derive the interval Taylor model of correlation function formula, and then get a quadratic exponential smoothing method based on interval the Taylor model. The proposed method has been tested on a provincial calculation. The results demonstrated the effectiveness and practical value of the approach by comparing with the results of Monte Carlo simulation and interval method.

Abstract: Temperature theoretical model of Ti-6Al-4Valloy during electrical discharge machining (EDM) process is established in this paper. Based on finite element thermal analysis, the temperature field of EDM Ti-6Al-4V on a single discharge is simulated with the aid of ANSYS software. The results show that there is a high temperature distribution around the spark point while the thermal-affected zone is quite small. Additionally, the profiles of discharge crater geometry have been predicted and the relation between crater shape and parameters under different current and pulse duration are also explored.

Abstract: Theoretical models of temperature and thermal stress for Ti-6Al-4V during electrical discharge machining (EDM) process are established. Based on finite element method, the temperature field of EDM Ti-6Al-4V alloy is simulated firstly with the aid of ANSYS, the results can be used to predict the width and depth of the spark crater. The simulated results show that there is a high temperature distribution at the spark point while the zone is quite small. The thermal stress field is estimated using the results of the temperature field as input. Surrounding the spark crater, the thermal stresses are concentrated, where may cause micro-cracks.

Abstract: A theoretical model of temperature for electrical discharge machining (EDM) is established. Based on finite element method, the distribution temperature fields of ZL108, YG15 and 45 carbon steel during EDM process are simulated with the aid of ANSYS software. The simulation model provides good effects on the surface quality forecast, parameter regulation and optimization in the process of EDM. Under same experimental conditions, the machining efficiencies of EDM ZL108, YG15 and 45 carbon steel are listed. The machining efficiency of EDM ZL108 or 45 carbon steel is much higher than YG15. The observations of YG15, ZL108 and 45 carbon steel surface micro-patterns after EDM are made by VHX-600 3D digital microscope. Form the experimental results, we can explain why ZL108 and 45 carbon steel are tractable metals, while YG15 is difficult-to-cut metal.

Abstract: A novel truing and dressing method, namely fiber laser assisted truing and dressing diamond wheel, is proposed to overcome the shortcomings associated with conventional mechanical dressing methods, ELID and ECD methods. A series of experiments have been conducted to prove that it achieves both high truing efficiency and good dressing quality. The finite element analysis of temperature distribution in fiber laser assisted truing and dressing diamond wheel using ANSYS is performed by author. Temperature field simulation helps to select optimized parameters under certain conditions.

Abstract: A novel truing and dressing method, namely dry electrical discharge (dry-ECD) assisted truing and dressing, is proposed to overcome the shortcomings associated with conventional mechanical dressing methods, ELID and ECD methods. The macro/micro complex feed mechanism in dry –ECD assisted truing and dressing equipment is designed to maintain continuous discharge between the tool electrode and diamond wheel in dry-ECD automatically. A series of basic performance experiments of the micro feed mechanism show that the position accuracy of the micro-feed mechanism is below 0.35μm using the micro-positioning control system. Whereas，the position accuracy of the mobile negative electrode is 1μm without macro/micro complex feed mechanism.

Abstract: Both diamond wheel and CBN wheel belong to super-abrasive wheels. Diamond wheels have superior grinding performance. The metal-bonded diamond wheel can grind hard brittle material component with a complicated shape precisely and efficiently. Because dielectric liquid is forbidden on numerical control optical profile grinder, the information on profile truing and dressing diamond wheel mounted on numerical control optical profile grinder is not readily available. In this paper, a novel truing and dressing method, namely dry electrical discharge (dry-ECD) assisted truing and dressing, is proposed. The experiments of dry-ECD assisted profile truing and dressing of diamond wheel are done by the authors. The experimental results show that both geometrical accuracy and surface topography of diamond wheel have attained technical requirement under appropriate truing and dressing conditions. There is not much difference in grinding abilities of new diamond wheel and dry-ECD assisted truing and dressing diamond wheel.