Advanced Materials Research Vols. 129-131

Abstract: The flow behaviors under different filling pressures were observed using electrode contact method. The relationships of recorded time and related point location were analyzed and deduced in terms of the flow tendency. The flow behavior figures were plotted at different time according the relationship. It was found that the unstable flow pattern takes place because filling cross-sectional area changes abruptly from the flow behavior figures. According to energy conservation and mass conservation theory, the relationship of flow velocity and filling pressure was established. Combining this relationship and critical flow velocity, the judgment equation of critical filling pressure was achieved.

Abstract: The flow behaviors of molten Al alloy in sand mould cavity with varied gating system were simulated under vacuum counter-pressure casting and the ingate velocity was predicted using a software package. At same process conditions, the flow behaviors were investigated using electrode contact method. The comparison between the simulated results and the investigated results shows that a good agreement is achieved. The ingate flow velocity exceeding critical velocity and large velocity deviation are detected during filling mould withⅠtypes gating system, resulting in turbulent flow behavior. Whereas, flow behaviors take on stable flow pattern during filling the other mould cavity, although some differences of flow behaviors are present. The small ingate flow velocity and velocity deviation during filling mould cavity with Ⅲ type gating system may be conduce the more stable flow pattern thanⅡtype gating system.

Abstract: The metal rubber is a kind of material for vibration control. In this paper, experimental research on characteristics of energy dissipation of metal rubber is exploited, and the relation between metal rubber stiffness and the amplitude of relative density and load. The relative between relative density and characteristics of energy dissipation is researched, in the excitation of displacement and load respectively. By comparing variation of the deformation and load with time, we found that the cycle of deformation and load is the same, but the deformation is still lag behind load. The research provided a basis for the application of metal rubber.

Abstract: According to the characteristics and control demand of coke oven, research on intelligent control of coke oven production process was carried. Firstly intelligent control structure of coke oven production process was established. Then intelligent control of blending coal, collecting main pressure, combustion and heating intelligent control of coke oven were discussed simply, while production planning and scheduling was discussed in detail. The control principle of combining the intermittent heating control with the heating gas flow adjustment was adopted, and fuzzy compound control was proposed to establish heating intelligent control strategy and model of coke oven, which combined feedback control, feedforward control and fuzzy intelligent control. Production planning and scheduling of coke oven were optimized by using dynamic programming and genetic algorithm. The practical running indicates that the system can effectively improve quality of coke and decrease energy consumption, stabilize production of coke oven, and has great practical value.

Abstract: Under low temperature and hot pressure molding process, the unidirectional C/C composites is prepared with PAN-based carbon fiber and AR-mesophase pitch. The effects of The heating program, heating time, the carbon fiber content, the temperature of pressure starting and pressure value on prepared sample are investigated. The morphology of C/C composites preform were characterized by polarizing optical microscope (POM). The results show that the optimization conditions are as follows: 60% of the carbon fiber content, 9h from 350°C to 550°C of heating time and the pressure of 44MPa at 450°C. The density of C/C composites compact preform is up to 1.43g ·cm-3 under the optimization condition.

Abstract: Using Gleele-1500D thermal simulation instrument, the effect of value of the current on synthesis of W-C-Co composites was investigated. It was shown that the nature of combustion products depended on the magnitude of the current intensity and the electric field was not only providing the Joule heat for a compact, but also accelerating the diffusion among atoms in the synthesis process. X-ray and microscopic analysis of combustion products suggest that the solid state reaction takes place at a relatively lower temperature by passing through the samples with current intensities between 20000 A and 30000 A. Moreover, as the current increases, the TTE becomes lower. At the same time, the relative strength of WC diffraction peaks in XRD diagram increases while that of W2C decreases.

Abstract: The model of flow press servo valve is built in this paper, during building the model, the author emphatically analyses the flow equation and force (torque) balance equation of every part of the valve, at the same time, all levels sub-models are organic combined according to power flow direction, signal flow direction of elements and causality, then we get the bond graph model of the flow press servo from this way. Adapting flow press servo valve and flow servo valve to concurrently control load system has its great advantage in restraining the superfluous force of the electro-hydraulic load simulator system, the performance such as load precision of system is enhanced greatly according to this method. Based on the system bond graph model, and by comparing the simulation curves and experiment curves, we can know that the simulation curves basically tally with the experiment curves, the bond graph models are validated right, which are flow press servo valve bond graph model and double valves concurrently control the electro-hydraulic load simulator system bond graph model. Simultaneity, the bond graph models in this paper take on generality, they are can be used on other aspects, such as other valve controlling cylinder system simulation, design and control strategy theory research.

Abstract: In the vacuum film coating field, the co-sputtering method by two or more targets has been widely used for coating the composite film consisted of a variety of component elements. In this paper, a typical co-sputtering system is studied which composes the twin round planar magnetron sputtering targets settled symmetrically and slantways towards a single flat substrate with self-rotation. A model is set up to describe the non-dimensional relationship between the film thickness and the structural parameters of co-sputtering system, such as distance of the substrate-to-target , symmetrical eccentricity , translation length and obliquity angle of target . On the assumption that the sputtered particles are emitted in the direction of cosine distribution and fly straightly without collision scattering, the depositing rate distribution, film thickness distribution, the utilization ratio of the target sputtering material, and the fluctuant ratio of the components from two targets are calculated. Some of simulating examples are given by use of Matlab software.

Abstract: It is difficult to fabricate one sensing element to simultaneously sense three linear acceleration components and three angular acceleration components, so as to find rare reports on six-axis accelerometer. The aim of this on-going project was to research an integrated six-axis accelerometer using parallel mechanism as the structure for sensing element. In order to optimize so many parameters, the paper defined the important static characteristic indices, analyzed the relationship between indices and structural parameters of sensing element. Based on the definition of the indices, the structural parameters were designed by the physical model of solution space. Finally, FEM simulation experiment is carried out to verify effectiveness of the method.

Abstract: As composite, the mechanical properties of coated fabrics are sensitive to environment. This paper presented mechanical properties under different environments. A list of uniaxial tests are carried out under different temperatures including -20°C, 0°C, 23°C, 50°C, and 70°C. First, the tensile behaviors at room temperature and the failure behaviors are studied. Then, the effects of temperature on mechanical properties are determined. Finally, the effects of water immersion on mechanical properties are discussed. Results show PTFE coated fabrics remained unchanged in varying temperature and humidity. The temperature has effects on the mechanical properties of PVC coated fabrics. With increasing temperature, the strength decrease and the strain at break increase. The temperature induction factors are proposed for the design and analysis. The water immersion has little effect on the mechanical properties because of the impervious coating.