Applied Mechanics and Materials Vol. 415

Abstract: High-speed milling of titanium alloys is widely used in aviation and aerospace industries for its high efficiency and good quality. In order to optimize machining parameters in high-speed milling TB6 titanium alloy, temperature distribution on the workpiece and the tool are analyzed, and the effect of milling parameters on milling force and milling temperature are investigated. The results show that the highest temperature appears on rake face, and near to the tool tip. With increasing of cutting time, heat affected zone on tool is bigger than that on workpiece. Milling temperature is most sensitive to the variation of milling speed, next sensitive to the variation of feed per tooth, and it is least sensitive to milling depth. Milling force is most sensitive to the variation of milling depth, next sensitive to the variation of feed per tooth, and it is least sensitive to milling speed.

Abstract: Aluminum alloy drill pipe used in deep drilling has great potential and broad field of application. Unlike steel drill pipe production method, aluminum alloy drill pipe is manufactured using forward extrusion in the horizontal hydraulic extrusion press to extrud internal/external upset ends with variable cross-section, and form an assembly line to produce aluminum alloy drill pipe. In this experiment, using 55MN double-action extrusion press on 7075 aluminum alloy tubing to get variable cross-section on one-shot, the extruded pipe body are in good surface quality wihtout cracks, laying the foundation for the forming technology of variable cross-section of aluminum alloy drill pipe.

Abstract: Copper tundish is used widely in continuous casting in steel production line. Tundish is coated by a special coating in the steel manufacturing. A coating experiment was developed to study the resistant of the copper material against the molten steel corrosion. High velocity oxygen fuel (HVOF) method was used to spray the alloy powder on the copper surface to form an alloy coating. However, the experiments are unreliability, waste of material and low efficiency. These would affect to the quality of the samples and spend more time and money to perform the experiment. Base on Teoriya Resheniya Izobretatelskikh Zadatch (TRIZ), this study improved the design of the experiment. After improvment, the average of alloy powder consumed per sample reduces 23.8%, and samples produced in this experiment are twice more than before. This improving will also be applied in other spraying processes.

Abstract: The processing of PPC/wood fiber foam composites using moisture as blowing agent was studied in this manuscript. Three important factors, such as: moisture content, wood fiber content and extruder die temperature were investigated with orthogonal design. The relationship between each factor and foam density was revealed, as well as the foaming mechanism was obtained.

Abstract: In order to solve the small cutting strip width and poor surface quality problems when spiral bevel gears are CNC machined by ball-end mills£¬a machining method of face milling spiral bevel gears by using a disc cutter with a concave end is presented. Based on the researches of spiral bevel gears geometry structure, through a bigger diameter disc cutter with a concave end selected, the setting order of cutter orientation angles changed, and the functions of cutter tilt and yaw angle separated, tooth surfaces machined with big cutting strip width and no bottom land gouge can be expected. Finally, taking a spiral bevel gear pair as an example, through machining and measurement experiments, the method feasibility and correctness are verified

Abstract: Layered carbon fiber composite performing microstructure was a part of multi-layer porous piping dielectric structure. At first a jet mechanism was put forward and researched for layered composite materials. The Z reinforcing fibers puncture was put to the layered composite structures. By the CFD simulation analysis, the feasibility of jet puncture was verified, the interlayer strength of the connection was increased and the Z bunch to the carbon fiber was eliminated, which laid theoretical foundation by enhancing the layered carbon fiber composite perform quality.

Abstract: Abstract. According to the electric potential on the eleven -needle electrodes in vacuum, the discrete equations based on the indeterminate linear charge density (LCD) are established by the boundary element integral equations. The non-uniform distributions of LCD on the needle electrodes are calculated through solving a set of linear equations. With the help of the LCD, the potential generated by the multi-needle electrodes at any point in vacuum have been obtained. In this paper we have realized the numerical calculation of the static field distributions for multi-needle electrode system by the boundary element approach.

Abstract: As increasing hydrogen demand for fuel cell application is expected in the near future, the efficient production of hydrogen is vital enabling technology for commercialization of fuel cell for residences and automobiles. Among different technologies of hydrogen production, autothermal reforming is considered to be thermally self-sustaining that the external heat source is not required. In this work, a steady state modeling of autothermal reforming of ethanol for hydrogen production has been performed. Because the operating condition at adiabatic temperature is designed for autothermal reformer, the estimated function of adiabatic temperature as function of steam-to-carbon (S:C) and air-to-carbon (A:C) molar ratios can be determined. At autothermal condition, the effect of S:C and A:C ratios on the product distributions of hydrogen rich stream is thermodynamically investigated. At fixed reactor pressure of 1 bar and preheat temperature of 200 °C, the favorable operating condition for the autothermal reforming of ethanol is found to be a S:C ratio of 2.0 and an A:C ratio of 1.75 at adiabatic temperature of 639 °C.

Abstract: This work presents the autothermal reforming (ATR), or called oxidative steam reforming (OSR), of ethanol for hydrogen production. A thermodynamic analysis of product distribution for ATR from ethanol has been performed by using the method of Gibbs free energy minimization. The effect of steam-to-carbon (S:C) and air-to-carbon (A:C) molar ratios under adiabatic temperature of ATR reactor on chemical equilibrium composition of hydrogen rich stream is investigated. An increase of S:C ratio increases an efficiency of hydrogen production while carbon monoxide formation decreases but, however, more energy consumption for preheating reactants is also needed. An increase of A:C ratio in the range between 0 and 1.75 causes an increase of hydrogen yield but at greater A:C ratio, a decrease of hydrogen production and more water formation can be found. The results of the thermodynamic equilibrium show that the predicted hydrogen composition in the reaction of fuel-water-air system at constant temperature is higher than that obtained from experiment in both the absence and presence of catalysts in the OSR reaction when the temperature is fixed at 700 °C. The predicted carbon monoxide is lower than that obtained from the results of non-catalytic reaction but higher than that attained from the presence of catalyst in process.

Abstract: This research study aimed to investigate the effect of main factors on the surface roughness in oil palm wood turning process for manufacturing furniture parts using carbide tools. The main factors, namely, cutting speed, feed rate and depth of cut were investigated for the optimum surface roughness in furniture manufacturing process. The result of preliminary trial shown that the depth of cut had no effect on surface roughness. Moreover, the experiment was found that the factors affecting a surface roughness were cutting speed and feed rate, with having tendency for reduction of roughness value at lower feed rate and greater cutting speed, Therefore in the turning process of oil palm wood, it was possible to determine a cutting condition by means of the equation R_a = 19.8-0.00742 Cutting Speed+3.98 Feed rate, This equation can be best used with limitation of cutting speed at 122-450 m/min, feed rate at 0.1-0.5 mm/rev and depth of cut does not over 1 mm,. To confirm the experiment result, a comparison between the equation value and an actual value by estimating a prediction error value was calculate with the surface roughness and margin of error does not over 10%. The experimental result reveals the mean absolute percentage error (MAPE) of the equation of surface roughness is 3.24%, which is less than the predicted error value and it is acceptable.