Advanced Materials Research Vols. 152-153

Abstract: In this paper, we investigate the mechanical properties of ceria and gadolinia doped ceria by molecular dynamics simulations. The doped concentrations and temperature dependence of yield stress and elastic modulus have been evaluated via uniaxial compression. Simulation results reveal that such properties decrease dramatically with higher temperature and doped content. In addition, the attenuated effect of doped content is more significant than that of temperature.

Abstract: Modified barium sulfate (MBS) /nature rubber(NR) composite materials were prepared by direct blending methods. Barium sulfate was modified by coupling agent Si-69, titanium esters and stearic acid. Tensile property, hardness and wear resistance of composite materials were studied by various methods. The results showed that the modified barium sulfate fillers had great effect on the reinforcement of the composites.

Abstract: Concrete is a sort of inhomogeneous and discontinuous diverse mixture, it has very complicated interior structure and working mechanism[1,2]. But the research about concrete constitutive relation and strength theory was based on the condition of concrete continuity. The law for microcosmic deform during concrete destroy was little considered[3]. Mechanism of shearing failure was researched through concrete sample’s experiment to explored interior microcosmic disharmony and the law of limiting strength release in this paper. Shearing experiments of concrete show shearing displacements of various local district in shearing surface during shearing have apparent discrepancy from beginning to end. This discrepancy leads to destroy of shearing surface from one local to another local and brings course of shearing limiting strength release discontinuous, one-off and non-instantaneous.

Abstract: Frequent starting and braking of vehicles causes rutting of asphalt pavement at urban intersection. As a result, dynamic response of pavement subjected to these kinds of vehicle loadings can be used to analyze rutting mechanism. At first, vehicle loading at urban intersection was described by a vertical and horizontal combined moving pressure with variable speeds. Then, three-dimensional finite element model in transient dynamic mode is developed based on the practical pavement structure. And the moving load, boundary conditions and material parameters were briefly introduced. Finally, through the comparison of time histories and spatial distribution among accelerating, decelerating and uniform motion, mechanism of rutting of asphalt pavement at urban intersections was illustrated according to the finite element simulation. It shows that frequent starting and braking of vehicle at urban intersections, obviously change the stress distribution within pavement structure compared with uniform motion case. The distribution and amplitude of maximum shear stress and horizontal shear stress was observed during the passage of the loading, which will result in shear flow deformation. Pavement structure subjected to moving load exhibits an alternative characteristic which will accelerate the rutting damage of pavement.

Abstract: A composite film consisting of ZnO and Chitosan (CS) is obtained on carbon steel via cathodic electrodeposition. Optimal CS concentration of electrodeposition of ZnO/CS film is determined by the method of polarization curves. It is shown that the ZnO/CS film obtained at the concentration of 0.6 g/L has the best corrosion resistance. The deposit is studied by scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR) and X-ray diffraction (XRD). XRD results indicate that ZnO could be fabricated by electrodeposition in composite film. FT-IR results evidence the existence of CS in composite film. SEM results demonstrate that the quality of film is improved because of the addition of CS. The anticorrosion property can be attributed to that the existence of the CS macromolecules can improve the stability of the composite film. This kind of composite film has an anticorrosion application for metal corrosion protection.

Abstract: A method for manufacturing composite ingot of 3004/4045 aluminum alloy using direct-chill (DC) casting was introduced. The casting process, the temperature distribution near the composite interface and the macro- and microstructures were investigated. The results show that composite interface is well-bonded, planar and clean with little evidence of porosity, which belongs to a kind of metallurgical bonding. Also semi-solid layer with a certain thickness is formed under the effect of cooling plate, which can ensure the realization of casting process of composite ingot.

Abstract: In connection with adverse effects of the single battery’s performance inconsistency of Lithium-ion batteries for electric vehicle, we’ve designed the battery management system and its balanced module. The systems based on MCU(Micro Controller Unit) STC12C5A60S2 accurately real-time capture and analyzes processing on the parameters of the battery pack, and then carry out function of balanced charge and discharge, management and protection by control circuit for battery pack. The results show that the system not only could make the charge and discharge of battery balance but also could effectively compensate the battery’s inconsistency, so that each battery has played the best performance.

Abstract: A statistical constitutive model, which takes account the effect of strain rate, was presented to describe the stress-strain relationship of brittle fiber bundles. To verify its reliability, tensile tests on two kinds of brittle fibers: glass fiber and SiC fiber, were carried out at different strain rates, and the stress-strain curves were obtained. It was found that the modulus E, the strength and the fracture strain of these fiber bundles all increase with increasing strain rate. The simulated stress-strain curves, derived from the constitutive model, fit the tested results well, which indicates that the model is valid and reliable.

Abstract: Al-4.5%Cu ingots were prepared by a process of low frequency electromagnetic casting (LFEC) and conventional direct chill (DC) casting, respectively. The effects of low frequency electromagnetic field on the microsegregation were investigated from eutectic analysis and electro probe microanalysis (EPMA). It was found that the amount of the nonequilibrium eutectic and the dimension of the nonequilibrium eutectic were decreasing markedly. In contrast, the solute content in the α-Al phase increased to a certain extent in the presence of the low frequency electromagnetic field, and it increased with the incerasing electromagnetic.

Abstract: Single-crystal PbTiO3 nanoflakes have been synthesized successfully by a hydrothermal method. The as-prepared powders were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and selected area electron diffraction (SAED). It was found that KOH concentration played a key role in the growth of single-crystal tetragonal perovskite PbTiO3 nanoflakes, and the morphology of PbTiO3 crystallites can be controlled by adjusting the KOH concentration.