Advanced Materials Research Vols. 472-475

Abstract: In this study, the factorial design and response surface methodology (RSM) was used to find the influence of manufacturing variables on the transesterification of plant oil into fatty acid methyl ester (i.e. biodiesel fuel) and to observe the variation of the degree of effect for each variable in the transesterification process with refined procedure. A second-order model was obtained to predict the viscosity and the yield of biodiesel fuel as a function of the reaction time, the mass fraction of catalyst in methanol and the molar ratio of methanol to plant oil. The experimental data of the yield and the viscosity of refined biodiesel fuels in different manufacturing variables are discussed in this study. Analysis of variance (ANOVA) was also applied to discuss the main factor and interaction factor effects of the manufacturing variables on the responses of the yield of biodiesel fuels. As shown in this study, the amount of catalyst affects the viscosity and the yield of biodiesel fuels. The yield of methyl ester is proportional to the amounts of methanol in the reaction. The factor of reaction time affects the viscosity and the yield of the biodiesel fuel slightly.

Abstract: Limited by supply voltage on board, control accuracy of low velocity and available torque of Control Moment Gyros (CMGs) gimbal driving motor are limited. Adding Harmonic Drive (HD) between driving motor and CMGs gimbal can improve CMGs control system performance. The paper establishes a practical HD model considering transmission, bearing friction, tooth meshing friction and compliance of flexspline. The model is properly simplified for analysing the control performance of whole closed loop system. Transfer functions are analysed and the flexspline output velocity is chosen to be the velocity feedback for controller according to the characteristics of CMGs gimbal velocity command. All of the numerical simulation results validate the theory analysis.

Abstract: A strength analysis on a large-scale horizontal vacuum tank, a dry equipment of the “ two million” large transformers, will be done in this article. Using the means of finite element analysis and two different unit-setting models, we compare the two results getting from the two units. Different lengthen styles of vacuum tank’s reinforced bead will be discussed, as well as different processing styles of welding parts model-setting in ANSYS.

Abstract: The process of short fiber reinforced injection molding is a typical multi-scale problem, it has become a cutting-edge issue of the field of polymer molding to study clearly the mesoscopic structure changing rules in the whole molding processing. Aiming at the processing of glass fiber reinforced polypropylene injection, basing on the foundation of macro continuum medium model, approximated short fiber reinforced injection molding process as macro-mesoscopic double scale problem composed by macro-flow and small-scale short fiber movement, establish the double scale model, which couple Mesoscopic fiber orientation. And the cooling crystallization model was established by learning from multi-scale simulation of liquid metal crystallization method.

Abstract: A vehicle model is built using the multi body dynamics software-ADAMS/ Car first. And then the vehicle’s performance of the constant radius cornering and ISO lane change is simulated. According to the simulation results, the handling stability is evaluated. The result shows that the ADAMS software can provide accurate simulation test and optimize the design plan of vehicle product.

Abstract: A method of the three-dimensional (3-D) simulation for warp-knitted fabric has been presented based on the characteristic structure of the yarn. And a 3-D model for warp loop structure has been established according to the NURBS curves. To make the simulation appear more realistic, a texture technology has been used for the loop model based on computer vision. Combining both Visual C++ and 3-D graphics processing technologies, a simulation program has been developed for the warp 3-D simulation.

Abstract: a numerical model research of fine-blanking has been built up. The fine-blanking process of parts with clearance 0.1%S, 0.7%S, and 1.3%S. (S stands for the thickness of the material) respectively, thickness of plate 2.9mm and diameter 16mm of steel 45, has been simulated. Through simulation, the study gets the material distribution situation of mean-stress fields in the progress of fine-blanking, and the author analyzes the relation between mean-stress fields and the crack of shearing zone. Through analysis the author concluded that the section quality grows with decrease of blanking clearance.

Abstract: In order to better solve asynchronous motor complex fault characteristics, improve the reliability of the diagnosis and accuracy, combined with wavelet transform technique, construct a wavelet neural network, wavelet transform technology feature extraction asynchronous motor as a signal wavelet neural network's input vector, and the wavelet neural network algorithm was used to optimize, realize the motor identify types of fault, through the simulation experiment data diagnosis results show that this method is effective and feasible. Based on the wavelet analysis and neural network fault diagnosis method of research.

Abstract: Synthesis of Ⅱa industrial diamond with high quality at high temperature and high pressure (HTHP) was examined in this paper and Ⅱa industrial diamonds were synthesized successfully. The experimental results show that the lowest synthesis pressure of diamond changed significantly which goes down firstly, and then up with the increasing of Ti content. It is discovered by optical microscopy that the color of synthesizing diamond in nitrogen getter system is lighter than that in raw catalyst power system and most crystals are hexahedrons & octahedrons. The experiment results measured by IR analysis shows that nitrogen content in synthesizing diamond in nitrogen getter system is significantly lower than that in the raw catalyst power system. Surface morphology of diamond synthesized in two different systems is investigated by the aid of SEM.

Abstract: 5-axis CNC machine is be the best tools in sculptured surfaces machining. Current CAM algorithms for 5-axis machining only consider the surfaces' geometric information when generating cutter contact points (CC points). Hence, the step length, which is the distance between two CC points, is determined only by the surface parameters for current CAM system. Because of the cutting tool can rotate, the actual cut trajectory is no longer a straight line between two consecutive CC points for 5-axis machining. Thus the cut error and the maximum step length should depend on the structural of 5-axis CNC machines tool and the surface's geometry. This paper proposed a new algorithm to estimate the maximum step length based on the cut error of 5-axis machining, and the result shows that this estimation algorithm provides better than traditional algorithms.