Applied Mechanics and Materials Vols. 130-134

Abstract: Nozzle is one of key parts in the diesel engine. The cavitation erosion of needle-sealing surface in the pintle nozzle has important influence on the fuel atomization, combustion and power performance of diesel engine. In order to investigate the effect of hardness of needle-sealing surface on cavitation erosion, two kinds of nozzles were selected and operated in S195 diesel engine for 10 hours. One nozzle is heat-treated one which has lower surface hardness; the other with higher surface hardness is real commercial nozzle. The surface appearances of original and operated nozzle-sealing surface were observed by SEM. It was found that the cavitation erosion on the seal surface of nozzle with lower hardness was severer than that of nozzle with higher hardness. However, their wear ways and formations are similar.

Abstract: In this paper TiN coating as an interlayer was fabricated on Q235 steel substrate by reactive plasma spray method and its microstructure and influences on the performance of the Fe/TiN/PO₂ electrode were investigated. It is shown that the TiN coating has a rough surface and layered cross-section structure. The coating consists of main TiN phase and a small quantity of Ti oxides. After heat-treated below 550°C the TiN coating is greatly densified due to the increase of Ti oxides, and however the electric resistance of the Fe/TiN samples is still lower than that of the Ti substrate. For the Fe/TiN/PbO₂ electrode a rougher surface and more micropores were observed in the active PbO₂ coating than on the surface of the Ti/PbO₂ electrode. Due to the presence of the TiN interlayer the Fe/TiN/PbO₂ electrode shows an accelerated life of 180h under the test condition, which is much longer than 28min of the Ti/PbO₂ electrode.

Abstract: The process of cutting granite material is simulated with using analysis of LS-DYNA finite element. The stress, strain and cutting force of a diamond saw blade are analyzed when cutting granite materials. Then the stress-strain distribution and cutting force curve of the diamond saw blade can be got in the process of cutting granite materials and a conclusion of the change rule of the cutting force is also obtained. When the diamond saw blade just contacts the workpiece, the cutting force rises gradually and after entering the certain cutting depth, the cutting force fluctuates in a very small range. Through the simulation, the theory of FEM model to calculate granite materials cutting force is obtained. By changing the parameters of the diamond saw blades, the influence of all parameters on cutting force of diamond saw blade is analyzed .A diamond saw blade's structure is optimized, when the parameters of saw blades is suitably selected. The processing performance of a diamond saw blade is improved further, and the result has important practical significance to process the granite material.

Abstract: The techniques of isothermal extrusion and mould are designed for the hilt of electric screwdriver. The deformation process is simulated with finite element method software-DEFORM-3D, the force of deformation for the hilt of electric screwdriver is predicted, is 250 KN. The Isothermal extrusion is processed by the pressure machine-YAW-500kN. The project of deformation and the correctness of simulation analysis are verified on the process experiment.

Abstract: With energy price and environmental pressure increasing, water-lubricated bearing has been further applied in ship propulsion system. By analyzing structure characteristic of propulsion system, especially propeller shaft system of the certain type of motorboat, the improving design is proposed that water-lubricated bearing made by new improved material of MC nylon is used to substitute the oil-lubricated bearing. The abrasion characteristics test for improved motorboat bearing is made, which is analyzed by way of comparison with material sample test to predict useful life, and its environmental suitability analyzed. The results show that the bearing improvement of motorboat propulsion system has met the using requirements, and improved propulsion reliability, lowered fuel consumption, avoided water pollution, saved maintenance costs, and been the significant social and economic benefits.

Abstract: In the high-speed, gyroscopic effects of the flywheel rotor greatly influence the rotor stability. The pole-zero points move to right of s-plane and the damping terms of the pole points become smaller. The stability of the system will get worse with the increasing of rotor speed when the traditional decentralized PD controller is used only. In the paper, a cross-feedback control with decentralized PD control is used for compensating gyroscopic effect. The simulation results show that the system stability is better using the cross-feedback control with decentralized PD control than using the traditional decentralized PD control.

Abstract: This title use the ANSYS Secondary Development Technology as platform, developed the user101 element that stable for fracture process simulation, and embedded fracture criterion into ANSYS software. Realized the fracture forecast on metal forming process and verified the simulation results through the experiment.

Abstract: As one of the key technologies, preparation of silicon nanospheres is very important for developing the new types of silicon based solar cells. In this paper, with the establishment of a novel electrical discharge machining (EDM) system and the raw material of heavy doped mono-crystalline silicon (0.01Ω•cm), silicon nanospheres of which diameter are ranging from 25nm to 280nm have been successfully prepared by using EDM method. The micro surface topography and the elements composition are analyzed by the SEM and the EDS methods respectively. The formation mechanism of nanospheres has also been studied.

Abstract: Metal materials wear loss against plant abrasive of different wear process was obtained by simulation test on the abrasive wear testing machine. On the basis of it, the GM (1, 1) model is established by using grey theory. Then the state of experiment data is divided using markov chain, the state transition matrix is constructed, finally the grey markovian model is established and wear prediction of metal materials against plant abrasive is gained. The results indicate that wear prediction based on the grey markovian model is more precise than the GM (1, 1), model, relative error being only 1.13%

Abstract: In this study,the chitosan (CS) -iron (Ⅱ,Ⅲ) oxide magnetic microspheres were prepared by crosslinking and coprecipitating with carbamide solution as precipitated agent.,and characterized by means of scanning electron microscope (SEM) and Fourier Transform infrared spectroscopy (FTIR ). The adsorption performance of the magnetic microspheres for remove Cr (VI) from aqueous solution was investigated.The experimental results demonstrated that the optimum of pH,time for adsorption of Cr (VI) was 3.3,120min at 25°C,respectly.