Applied Mechanics and Materials Vols. 401-403

Abstract: For the purpose of developing an effective Fe₂O₃-doped nickel-based catalysts to be used in biomass gasification, Fe₂O₃ nanoparticles were prepared by homogeneous precipitation method involving an aqueous solution of Fe (NO₃)₃·9H₂O and urea as precipitator. Different approaches, such as XRD and SEM, were used to characterize the products. Meanwhile, the effects of various technical parameters in preparation process on the yield of products were investigated, and optimal conditions for preparing Fe₂O₃ nanoparticles were found as follows: the molar ratio of urea to Fe (NO₃)₃·9H₂O for 5:1, temperature of precipitation reaction for 125°C, concentration of iron salt for 0.20mol/L. The Fe₂O₃ nanoparticles prepared under the optimal conditions were spherical in shape and well dispersed; they had high purity and a fine crystal phase of cubic syngony with a mean particle size of about 28nm.

Abstract: The surface of Kevlar fiber was modified by hydrogen peroxide solutions (H₂O₂) in this article. The interfacial properties of Kevlar fiber/epoxy composites were investigated by the single fiber pull-out test (SFP). The results showed that the interfacial shear strength (IFSS) of Kevlar /epoxy composites was remarkbly improved after surface modification and the breaking strength has not been affected appreciably. It provided an efficient method to make the surface modified Kevlar fiber for the application for the advanced composites at a lower production cost.

Abstract: ntelligent temperature-controlled fiber can perceive changes in the environment and correspond accordingly subject to stimulation of certain conditions. In the functional innovation, the intelligent fibrous material modifies the nature of conventional synthetic fiber and the original performance of natural fiber and chemical fiber. Through in-depth analysis of the existing achievements, strive to explore the application prospect of intelligent temperature-controlled fiber starting from the internal structure of textile fibers.

Abstract: In this paper, a research work on the hole shape distortion of commercial-purity aluminum plates in the bending process was carried out. The bending process was simulated by using ABAQUS software in order to reveal the phenomenon and law of hole shape distortions near deformation area. A series of bending tests were conducted for the comparison of simulation results. By measuring the hole diameter under different conditions, the factors that affect distortion level were obtained, including hole distance and initial plate thickness. The rationality of this distortion law was proved by finite element simulation. This research provided the plate with a hole of theoretical basis for bending process selection of the most suitable process parameters.

Abstract: Reinforced rib is used to strengthen the rigidity of thin-walled casing structure , inhibit the vibration of the structure effectively. In this paper, Finite Element Method is used to simulate the typical reinforced rib thin-walled casing structure. Changing the reinforced rib positions and geometric parameters such as sizes, then calculate the stiffness to weight ratio and dynamic response, at the same time ,make a comparison. The result shows that: The thin-walled case with reinforced rib, the tensile stiffness and bending stiffness were increased, but the stiffness to weight ratio is presented in different geometric parameters shows differents; Under the different frequencies of excitation force load, because of the reinforced rib, the thin-walled casing structures harmonic amplitude decreases when they are under the same frequency .The result will provide reference for later thin-walled case with reinforced rib structure design.

Abstract: For describing and resolving the process of chromium ore smelting reduction preferably, the research status on the thermodynamics and kinetics of chromium ore smelting reduction process was summarized, based on the introduction of the process for smelting stainless steel with hot metal in a converter. The existing problems for smelting stainless steel by chromium ore smelting reduction in a converter were also discussed and some suggestions were made for the future work. A lot of investigations about the thermodynamics and the reduction mechanisms of chromium ore have been done. However, the consistent view about the thermodynamic feasibility and the mechanism of smelting reduction has not been achieved, so the application of research results is limited. Little work about the reaction kinetic model for the production of stainless steel by chromium ore smelting reduction and direct alloying has been done. So the synthetic kinetic model including a dissolution model and a reduction model of chromium ore should be built to predict and control accurately the process.

Abstract: The structural transitions of the rapidly cooled Ti₇₅Al₂₅ under high pressures were studied by using molecular dynamics simulations. This work gives the structural properties, including the potential energy, pair-correlation function, Honeycutt-Andersen (HA) and Voronoi indices, and temperature dependence. Our results indicated that the liquid Ti₇₅Al₂₅ was frozen into glass state at the temperature about 300 K under different pressures during the same quenching processes. With increasing of pressure, the glass transformation temperature (T_g) become high. The icosahedral and defect icosahedral clusters increase as the temperature decreases under different pressures. But the icosahedral cluster increases with the increasing pressure and defect icosahedral clusters keeps invariability at 300 K.

Abstract: The epoxy resin was modified with the mixture of α,ω-dihydroxy poly-(3,3,3-trifluoropropyl) siloxane (PTFPMS), KH560 and stannous octoate. KH560 can react with PTFPMS and also epoxy resin curing agent. The two reactions were characterized by FI-IR. The modified epoxy resin was characterized by FI-IR. The result showed that fluorine-containing silicone had been successfully introduced into the epoxy system. The mechanical and thermal properties of the modified epoxy resin were analyzed. The results showed that with the increase of PTFPMS the impact strength of epoxy resin increased, hardness and bending strength correspondingly reduced, slight decrease in the glass transition temperature.

Abstract: The research status of crystallization process and crystallizer of gypsum is introduced in this paper. Progress in 3D mathematical simulation of crystallizer based on Fluent is summarized, and the application of the 3D model in the construction and optimization analysis is also described. Furthermore, the prospect of Fluent applied in the design and optimization of gypsum crystallizer is introduced. Finally, the potential and prospect of Fluent basing on the 3D mathematical simulation of crystallizer in the production of gypsum is put forward.

Abstract: With the carbon fiber reinforced plastic(CFRP) materials more and more widely being used in aviation, aerospace and other industries, the study of the secondary processing technology of composite materials is paid attention by scholars from home and abroad. Because the composite materials has characteristics such as high hardness, high strength, light weight, anisotropic and etc, it is easy to produce hierarchical, tearing, burrs, drawing, the collapse of block and other defects in the machining process, so it belongs to a typical difficult-to-machine materials. Firstly the type and characteristics of carbon fiber composite materials were analyzed. Basing on the basic principles of composite material machining the carbon fiber composite machining defects were analyzed, and the design and optimization suggestions of the carbon fiber composite cutting tool were put forward according to its machining characteristics. The tool solutions of the drilling problems of carbon fiber composites in different areas currently facing were explored. Under the basis of theoretical research and analysis, a new type of PCD tool was designed and developed and through comparing test the optimal edge was got. Through experimental research the tool geometry parameters and cutting parameters which were suitable for machining were analyzed, and the tool life problems were analyzed too. All these laid a foundation to realize carbon fiber composite materials cutting of high efficiency and high quality.