Advanced Materials Research Vols. 482-484

Abstract: Bambusa distegia were used to make bamboo thread plywood by the process of producing thread, dipping thread into glue, assembling pattern and pressing. Influence of hot pressing pressure on mechanical properties of bambusa distegia thread plywood was investigated, which was 2.0MPa，2.5MPa，3.0MPa，3.5MPa and 4.0MPa respectively. The results indicate that the modulus of rupture(MOR), modulus of elasticity(MOE), compressive strength(CS), and horizontal shear strength(HSS) increase with the increasing of hot pressing pressure. Mechanical properties of the Bambusa distegia thread plywood are higher than the indices of plywood for concrete form and the indices of plywood for container flooring.

Abstract: This paper used the solid modeling software to establish the turbocharger compressor internal flow model and the compressor flow field grid model. It simulated the turbocharger compressor assembly three-dimensional viscosity steady flow characteristics in use of FLUENT6.3, and analyzed the internal flow field of the compressor under different working conditions. Then on the basis of that, proceeded the noise analysis of the turbocharger compressor, which provides theory basis for the design of turbocharger compressor noise reduction.

Abstract: In order to study the relation between the velocity of moving load and the rail deformation, a mechanical model about rail elastic support was built for a existing wheel/rail system monitoring equipment's physical model. Combining the boundary conditions and load type, the oscillation equation of rail mechanical model was solved via Vibration superposition method. Analysis the dynamic response of rail under different moving load range from 40km/h to 200km/h by MATLAB.The law of the relation between rail deformation and the velocity of moving load was got. That is the deformation of rail decrease when the velocity of the moving load increase.

Abstract: Based on the sound intensity measurement and analyzing, the noise radiated from the washing machine with horizontal axis was discussed to identify the noise source and find its propagation path. According to the principle of the sound intensity measurement, the measurement grids were arranged at the outside surfaces of the washer, and the distance was set to 20cm. The result showed that the noise source was near the right surface of washer’s motor installing. The maximum sound intensity values are mainly in frequency bands of 2 KHz and 4 KHz. Back surface of washer with sound power level 51 dB radiated the maximum sound intensity value 55.8 dB for 2 KHz and 56.0 dB for 4 KHz. There was also appeared the maximum sound intensity of low frequency 100 Hz in Right surface, which was caused by the vibration of motor transferring to the right surface shell. The results can provide technology support for the noise control of washing machine.

Abstract: AlN/epoxy (AlN/EP) composites were fabricated by casting method. The effects of the AlN content on microstructure, thermal conductivity and thermal expansion properties of composites were investigated. The results indicate that with the AlN content increasing, the thermal conductivity increase, while the coefficient of thermal expansion (CTE) decreases. When the volume fraction of AlN is 25%, the thermal conductivity is 0.507 W/m•K, which is about 2.5 times higher than that of the epoxy matrix, while the coefficient of thermal expansion is 53.7 ppm/°C. The thermal conductivity results obtained were also analyzed using the Maxwell-Eucken model to explain the effect of AlN fillers on the formation of thermal conductive networks.

Abstract: Seismic responses can strongly determine damages of bridge structures, e.g. due to pounding and unseating of girders as observed in many major earthquakes in the past. In the investigations often uniform ground excitation and pounding at only one location are considered. Studies on the influence of non-uniform ground excitation on bridge responses are still very limited, and they are restricted to flat ground-surface condition. Influence of multi-sided pounding is also not much investigated. If the impediment effect of abutments is considered at all. The study reveals that commonly assumed girder stiffness for the end restraint overestimates the actual effective end-restraint stiffness. Non-linear elastomeric bearings can significantly reduce the adjacent girder relative displacements. A consideration of non-uniform excitation is essential for a realistic estimation of bridge response and damage potential.

Abstract: Based on the analysis of the characteristics of tractor clutch and the engagement process at start-up working condition, the dynamics model of the clutch start-up working condition is established, then clutch engaging control approaches are discussed with emphasis, therefore the clutch engaging control law of “fast-slow-fast” is obtained. According to the clutch control strategy, clutch simulating analysis of an AMT tractor at the starting conditions will be in process by Matlab/Simulink on the basis of well design of fuzzy controller. The analysis result shows that the use of fuzzy control theory could effectively control the engagement process of AMT tractor clutch at start-up working condition.

Abstract: The two infinitely long surfaces in line contact under thermoelastohydrodynamic lubrication with solid-liquid lubricants were investigated. The time-dependent modified Reynolds equation elasticity equation and the adiabatic energy equation have been formulated and solved numerically with initial conditions using multi-grid multi-level method with full approximation technique. The characteristics of the two surfaces in line contact under thermoelastohydrodynamic lubrication were presented as; film pressure, film temperature and oil film thickness profiles. The results of solid-liquid lubricants with micro-particle and nano-particle under thermal elastohydrohynamic lubrication were compared with the case of pure liquid lubricant.

Abstract: The solidification structure applying a novel low-voltage alternating current pulse (ACP) during solidification of Al-7Si-0.52Mg alloy has been investigated. The results indicated that the grain density increased with increasing current density. A remarkable refinement of grain occurred, and the microstructure of primary α-Al phase transforms from developed dendrites to fine rosette equiaxed grain when the current density was more than 230 Acm^-2. The grain refinement was mainly achieved during the nucleation stage rather than the stage of liquid inoculation and dendrite growth. It was concluded that the grain refinement under ACP during nucleation stage was due to the enhancement of nucleation rate induced by an additional electric potential energy.

Abstract: Retained austenite of Q&P (Quenching and Partitioning) processed 0.2C-1.51Si-1.84Mn steel heated in intercritical region and full austenite region are investigated. The results show that the maximum volume fraction of retained austenite heated in intercritical and full austenite region is 13.39% and 5.23% respectively. Carbon partitioning completed within 10 s for both heating modes. The microstructure after full austenitization consisted of martensite laths and thin, inter-lath retained austenite film. Austenite blocks is observed as well after partial austenitization.The distribution of retained austenite is related to the amount of grain boundaries by EBSD techniques.