Advanced Materials Research Vols. 228-229

Abstract: There are much complex internal microstructures of functionally graded materials, and the mechanical parameters of functionally graded materials structures varied with the space coordinates. Therefore, it is generally difficult to measure point by point macro distributions curves of functionally graded materials properties based on available experimental conditions. The prerequisite for various analyses of the functionally graded materials structures is the determination of macro distributions curves of materials properties parameters. In practice, only the spatial distributions of different material components can be controlled in the course of materials production. Therefore, the functionally graded distributions curves need inversing and identifying by the materials components. In the present paper, the inversion and identification technique was put forward based on the positive static and dynamic analyses by the microelement method, which was applied to do the scale-span analyses for macro responses of functionally graded materials structures based on the given materials components distributions in production.

Abstract: Basing on the theory of the meshing principle and the differential geometry, deduced the contact wire function for the new sine gears. In explanation of the gear parameters influencing to the contact wire function, imitated the contact function using the regular changes values of the amplitude value H and the helix angle β with MATLAB. From the imitation derived the evolution of the contact wire influencing by the amplitude value H and the helix angle β. The contact wire moved following with the enlarge amplitude value H to the forward direction of the high tooth and the forward direction of the width tooth; The contact wire also moved following with the enlarge helix angle β to the negative direction of the high tooth and the negative direction of the width tooth. Thereby, in order to select the appropriate gear parameters provided basis.

Abstract: Vehicle’s sliding resistance mainly includes rolling resistance, air drag resistance and friction within the transmission, wheel bearings and other related components. Among those, rolling resistance and air drag always exist whenever vehicle is running, so they have great influence on vehicle’s dynamic performance and fuel economy. Therefore, it is important to determine vehicle’s rolling resistance coefficient and air drag coefficient quickly and accurately in order to operate vehicle properly and reduce the vehicle’s fuel consumption. Combining theoretical analysis with experimental verification, calculation model based on road coasting test was given by means of least squares principle. And through which vehicle rolling resistance coefficient and air drag coefficient were determined easily. Then by using the test data from some Minibus, the vehicle's rolling resistance coefficient and air drag coefficient are calculated according to established model. The computation result shows that rolling resistance coefficient is a linear function of the speed and the air drag coefficient is constant. Finally, the analysis shows that the calculation model is simple, precise and useful.

Abstract: The fixture of motorized spindle significantly affect the vibration of micro high speed CNC milling machine, its performance can directly affect the machining accuracy of the entire micro milling machine. A special fixture of high-speed motorized spindle is designed in the paper and its static characteristics are checked by utilizing ANSYS finite element analysis software. To guarantee the sufficient strength of bolts and the safety of motorized spindle when the motorized spindle runs at high speed, theory analysis method and ANSYS finite element analysis method are used to make the strength check of the fixture. The designed special fixture for high speed motorized spindle plays an important part in the design of high-speed motorized spindle.

Abstract: Deformation dilatometry has been used to simulate controlled hot rolling followed by controlled cooling of a Nb microalloyed pipeline steels, the microstructure and transformation characteristics in the steel and the effect of deformation on transformation are studied. According to the results of both dilatometry measurements and microstructure observations, the continuous cooling transformation curves (CCT) of the tested steels are constructed. The results show that Nb content and deformation enhance the formation of acicular ferrite; the microstructure of the steel range from PF, QF to AF with increasing of cooling rates from 0.5 to 50°C /s in a two stages controlled rolling and the microstructure revolution is sensitive to cooling rates when it is lower than 5°C /s, however, when the cooling rate increasing further, the microstructure didn’t change very much but M/A constituents in matrix is refined and dispersed.

Abstract: The microstructure and pickling characteristics of oxide scale formed on hot-rolled SPHC steel strip produced by different processes were investigated based on structure observation, weight loss and corrosion potential measurements. The results show that the scale formed on strip produced by TSCR consists of mainly magnetite (Fe3O4) and little wustite (FeO), hematite (Fe2O3), and that in conventional process is composed mainly wustite (FeO) and little magnetite (Fe3O4), hematite (Fe2O3). The shape of the open-circuit potential transient is determined crucially by the oxide scale structure. Time to reach a steady-state value of open-circuit potential of strip produced by TSCR is longer than that in conventional process. Both the stability of the scale in pickling solution and the effectiveness of descaling could be evaluated and predicted by measuring the change of electrochemical potential during acid pickling.

Abstract: A kind of nonfunctional silsesquioxane (SSQ), methylsilsesquioxane (Me-SSQ), was used to modify cyanate ester resin (CE) in this paper. First, methylsilsesquioxane (Me-SSQ) was synthesized by the hydrolysis and condensation of methyltriethoxysilane. Then a series of Me-SSQ/CE hybrids containing 0wt%, 1wt%, 5wt%, 10wt% and 20wt% of Me-SSQ were prepared. The effect of Me-SSQ content on the curing behavior and thermal properties of materials was investigated by using Fourier transforms infrared (FT-IR) spectroscopy and thermogravimetry (TG), respectively. FT-IR results indicate that the addition of Me-SSQ does not show significant effect on the conversion of CE. However, TG data show that Me-SSQ improved the thermal properties of CE greatly.

Abstract: To determine the optimum process parameters and loading paths for T-branch tube compound bulging using rubber medium, a finite element model was established at the software platform of ANSYS/LS-DYNA. Tubular blank parameters were optimized while the affections of blank parameters and frictions in bulging process were analyzed, during which Taguchi method, sensitivity analysis and normalization method were adopted and an evaluation function is inducted. The Taguchi method was used to establish a design of simulation schemes, and numerical simulations were carried; a sensitivity analysis was carried out with analysis of variances to seek the significance of parameters; the evaluation function was inducted to synthetically evaluate the affections of the thickness variation and the branch height and normalization method are applied to ensure equality of two sets of data in the evaluation function. Then the execution method and loading path of counter force for compound bulging process were designed and an ideal T-branch tube was gained at last.

Abstract: At present the study on the application of the topology optimum design in scraper conveyor is still under development. In this paper the topology optimization based on the homogenization method is applied to the design of the baffle on the scraper conveyer, which can provide a valuable conceptual design scheme for the selection of the baffle pattern. In conjunction with the homogenization theory and Finite Element Method (FEA), the mathematical models for designing the baffle by the minimizing mean compliance are developed in this paper. By applying the topology optimum design to the baffle, the topology optimization based on the homogenization method is proved to be reliable and practical at the conceptual design stage of baffle.

Abstract: Behavior of Cr-rich phase in rapid solidification Cu71Cr29 alloys was investigated by using melt spinning and splat quenching. The microstructure and solidification behavior of the Cr-rich were investigated by scanning electron microscopy (SEM). The results showed that the alloys generally have a microstructure consisting of a fine dispersion of a Cr-rich phase in a Cu-rich matrix. However, the morphology and size of the Cr-rich phase vary greatly with the cooling rate. On the one hand, the average size of the Cr-rich phase is reduced with increasing cooling rate. On the other hand, the Cr-rich phase show both dendrites and spheroids for lower cooling rate but only spheroids for the higher cooling rate. This means liquid phase separation occurred during rapid solidification. The results were discussed with respect to the formation of the Cr-rich spheroids during rapid solidification.