Advanced Materials Research Vols. 472-475

Abstract: Computational Fluid Dynamics (CFD) method was adopted to establish the three dimensional model for cathode gas channel of planar SOFC and simulate the gas flow in the channel of a single cell. A quantitative analysis method was presented to research the status of gas flow. The characteristics and diagram of velocity change were obtained by using the quantitative analysis method. Furthermore, it was found that gas leak has a negative effect on the uniformity of gas flow, which is more obvious in the region near the leak side.

Abstract: Tool life and the rationality of cutting parameter setting are evaluated directly by cutting force. In order to predict cutting force, and then to optimize the tooth cutting condition for dry high-speed spiral bevel and hypoid gear cutting, this study has established a 2D cutting FEM simulation platform by using DEFORM-2D based on the 2D orthogonal slot milling experiment. Through the platform, using the method of combining single-factor experiment and multi-factor orthogonal experiment, this study has explored the influence of cutting/tool parameters on cutting force in the dry high-speed cutting process of 20CrMnTi spiral bevel and hypoid gear (face hobbing dry cutting process). The results show that from high degree to low degree, the influence of each parameter on cutting force is as follows: feed > cutting speed > relief angle(P.A.side) >blade rake angle, and the influence of the first three parameters is significant, the influence of blade rake angle is not significant; the optimized condition for dry high-speed spiral bevel and hypoid gear cutting is suggested to be: the cutting speed is 300 m/mim, the feed is 0.06 mm/r, the blade rake angle is 14° and the relief angle(P.A.side) is 10°; the cutting edge can be honed moderately, but the hone radius is not bigger than 0.1 mm.

Abstract: The modeling approach of spatial parallel manipulator has been extensively studied based on the SOC theory in this paper. According to the characteristics of the parallel robot mechanism’s , ideas and general methods of spatial parallel manipulator modeling in parallel has been proposed and typical spatial mechanism’s modeling has been performed. Study shows that the parallel modeling approach can dramatically increase the modeling and solving efficiency for parallel manipulators.

Abstract: With manufacturing industry tending to high-mix low-volume production, the turn-mill machining technology has recently received much attention. This research proposes the programming method using process planning and kinematic based on the existing problems during the course of the programming for the mill-turn machine. Firstly, through computing the volume of removal shape on the cylindrical blank shape, dividing the machining process for the spindles. Then recognizing the turning and milling process and computing their removal shape for obtaining tool path. According to complex configuration of the mill-turn machine, the machine kinematic chain is created to convert cutter location data generated into the NC data. Finally the effectiveness of the programming method is confirmed by machining experiment.

Abstract: The BCB (BaCu(B2O5)) powders were synthesized by solid state reaction method and its effects on the microstructures, the phase formation and the microwave dielectric properties of MCT (Mg0.95Ca0.05TiO3) ceramics were investigated. BaO and B2O3 first forms BaB2O4, and then BaB2O4 reacts with CuO forming BCB. The sintering temperature of MCT ceramics with as-synthesized BCB addition can be effectively lowered from 1450°C to 1100°C due to the liquid phase effect. The formation of second phase (MgTi2O5) was restrained. The 3wt% BCB-doped MCT ceramics sintered at 1100°C for 3h have optimum microwave dielectric properties of Kr=21.5, Q×f=28000GHz, and TCF=-3.3ppm/°C. Obviously, BCB could be a suitable sintering aid that improves densification and microwave dielectric properties of the MCT ceramics.

Abstract: In order to understand the demand characteristics of housing security and improve the implementation effect of security policies, the subdivided family lifecycle of low-income family housing need was analyzed by fuzzy clustering with some Harbin samples, and the characteristics of various stages of housing security need, which was meet by four modes, such as “high subsidy +cheap-rent housing”, “rent subsidy”, “home ownership subsidy+ affordable housing”, “low rent subsidy + public rental housing”. The study has positive theoretical significance and practical value on the housing security policy.

Abstract: Among all manufacturing processes, forging has a special place because in this technology, parts with desired mechanical properties and minimum waste of material can be produced. Gear is one of the components of machinery which should have special features such as high strength-to-weight ratio, fatigue and surface abrasion resistance, etc. So, comparing with other methods, gear forging provides above requirements. Moreover, precision forging of gears is one of the appropriate methods for producing this piece because it saves material consumption and reduces machining costs. Extensive studies are carried out on this production method but there are also many aspects to be investigated. Since, without having knowledge of the influence of parameters such as friction conditions, material properties, and geometry of work piece on the mechanics of the process, optimal design of the form, selection of appropriate equipments, and prediction and prevention of defects that may occur is not possible, modelling the process for computer simulation has been given much attention in modern technology of metals forming. The purpose of this study is to examine factors such as number of teeth, modulus and coefficient of friction on load, and the force required for the process which has been studied using finite element method.

Abstract: There were problems of strong electromagnetic interfere (EMI) and floating of ground potential when the electrothermal-chemical gun (ETCG) was launched. EMI seriously affected the chamber pressure measurement, and affected the accurateness of data and the security of apparatus. The chamber pressure testing technology was put forward which adopted the field testing technique with digital storage and the digital optical fiber transmission technique. The on-site storage pressure gauge and multilayer electromagnetic shielding structure was designed. Test data real-time transmission and remote reappear are realized by using high speed digital optical transceiver module and optical fiber. This testing technology effectively solved the EMI problem, improved the reliability and safety of chamber pressure measurement. The test data provide a basis for research of interior ballistic properties of ETCG. This testing technology can be widely applied to the parameters measurement with strong electromagnetic interfere.

Abstract: Accuracy of machined workpiece is one of the most important considerations for any manufacturer. The present study aims to establish a new algorithm for evaluating the cutting Error in five-axis free-form surface milling for table-tilting type machine. The cutting error evaluating algorithms consider the kinematics of the machine and the tool geometry as well as the local geometries of the machined free-form surface. Based on these algorithms, the present study develops a new error compensation method. Finally, experimental results show that the tool paths generated by the present procedure have better machining efficiency.

Abstract: The high gas velocity electrostatic precipitator (HGVESP) is simulated by computational fluid dynamics (CFD) technology. The SIMPLE algorithm is used to calculate and the geometry model is divided by pre-processing software ICEM. The relationship of gas velocity, dust particle size and voltage is examined by FLUENT. The results suggest that with the improvement of applied voltage and dust particle size, collection efficiency increases. The results show that HGVESP with transverse plates can not only have a high efficiency, but also increase treatment capacity, which achieve miniaturization. Then the correctness of the model is verified by experiments.