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Janine Glänzel Arnd Meyer Roman Unger Michael Bräunig Volker Wittstock Steffen Ihlenfeldt 《The International Journal of Advanced Manufacturing Technology》2017,88(5-8):1279-1288
A new interdisciplinary approach is discribed to identifying unknown parameters using an extended version of the known interval bisection method. This developed method is based on the use of finite elements for calibrating the simulation calculation. The resulting thermo-elastic deformations which occur in drilling processes with impaired cooling lubrication are to be used as correction values for tool positioning in the NC control. Based on the strong impact on workpiece temperature of machining, a simulation approach is presented for calculating the temperature fields and their thermo-elastic consequences. In addition, methods are presented to correct these effects. This paper particularly deals with the temperature fields of drilling operations. Special attention is paid to the technique employed for iterative numerical determination of the unknown heat flux η w and heat transfer coefficient \(\bar {\gamma }\) values. Finally, the data obtained from experiments are compared with those achieved by numerical simulation in order to verify the efficiency of simulation and determination of parameters. 相似文献
996.
胡卫兵 《武汉理工大学学报(材料科学英文版)》2016,31(4):722-726
In order to establish a simple, sensitive, and fast reliable detection method to determine the magnolol, FeWO4 nanoflower was synthesised through a solvothermal technique and FeWO4 nanoflower modified carbon paste electrode (CPE) was developed. The voltammetric behavior of magnolol on the modified electrodes was studied using cyclic voltammetry (CV), linear sweep voltammetry (LSV), and differential pulse voltammetry (DPV). The experimental results showed that the modified electrode remarkably enhanced the electrochemical response of the magnolol and exhibited a wide linear range for determination of the magnolol from 1.0×10-7 to 1.0×10-4 mol/L with a low detection limit of 5.0×10-8 mol/L. 相似文献
997.
胡春秀 《武汉理工大学学报(材料科学英文版)》2016,31(4):818-822
A new corona protection varnish was prepared by using epoxy/montmorillonite nano-composite and pure epoxy resin as adhesives respectively. The adhesive with different amounts of organic montmorillonite (OMMT) was mixed with 1200 mesh silicon carbide (SiC) by different weight ratios. The surface states of the varnishes with various adhesives were observed by powerful optical microscope. Some properties of the varnishes were analyzed during the enduring time under 5kV/cm DC, such as the relation of change in nonlinear coefficient, natural surface resistivity, and surface temperature variation. The results showed that the amounts of OMMT had little effect on the natural surface resistance of the varnish but had important influence on the nonlinear property of the varnish. When the range of the OMMT content was 2wt% to 6wt%, the nonlinear coefficient of all materials with epoxy/OMMT nano-composite adhesive was higher than that with pure epoxy resin adhesive. The surface temperature of the varnish with epoxy/OMMT nanocomposite adhesive was all lower than that with the pure epoxy resin adhesive under high electrical field strength. 相似文献
998.
何峰 《武汉理工大学学报(材料科学英文版)》2016,31(6):1267-1271
Influence of aluminum addition on the structures and properties of SiO2-B2O3-Al2O3-CaO vitrified bond at low sintering temperature and high strength was discussed. FTIR and XRD analyses were used to characterize the structures of the basic vitrified bond with different contents of aluminum. The bending strength and the thermal expansion coefficients were also tested. Meanwhile, the microstructures of composite specimens at sintering temperature of 660 °C were observed by scanning electron microscope (SEM). The experimental results showed that the properties of vitrified bond with 1wt% aluminum were improved significantly, where the bending strength, Rockwell hardness, and thermal expansion coefficient of the vitrified bond reached 132 MPa, 63 HRB, and 6.73×10-6 °C-1, respectively. 相似文献
999.
Haythem?GajaEmail author Frank?Liou 《The International Journal of Advanced Manufacturing Technology》2016,86(9-12):2913-2925
Any shortfall in the required depth during milling machining can affect the dimensional accuracy of the part produced and can cause a catastrophic failure to the machine. Corrective remedies to fix the dimensions inaccuracy will increase the machining time and costs. In this work, a depth-of-cut monitoring system was proposed to detect depth of cut in real time using an acoustic emission sensor and prediction model. The characteristics of the sensor signal obtained in machining processes can be complex in terms of both nonlinearity and nonstationarity. To overcome this complexity, a regression model and an artificial neural network model were used to represent the relationship between the acoustic emission signal and the depth of cut. The model was tested under different machining cases and found to be efficient in predicting the depth of cut. 相似文献
1000.
Md.?Kamrul?Hasan Katsuhiko?SasakiEmail author 《Journal of Mechanical Science and Technology》2016,30(7):3085-3095
Finite element analysis (FEA) has been carried out with the aim of understanding the thermal deformation characteristics of two solar cell configurations. One of the solar cell models is tabbed by lead-free solder, the other model by Conductive film (CF). A high temperature soldering process could weaken the bond and reduce the reliability of the cells because of the residual stress caused by the different thermal expansion coefficients of the materials. Moreover, solar irradiation generates temperature distribution across the surface of the solar cell, and the development of solar cells made of thinner crystalline silicon wafers will lead to the reduction in manufacturing costs. In this study, Finite element analysis (FEA) of the manufacturing process has been carried out using both solder and CF bonding. Three temperature cycles were applied to analyze different environmental operating conditions and understand how thermal cycles affect the residual stress during actual service conditions. This investigation provides a comparison of thermal deformations between solder and CF bonded solar cells in order to understand which offers substantial reliability in the long term. Also this study explores the effects of various thicknesses of the silicon wafer on the residual stress and deformation of the solar cells. 相似文献