Applied Mechanics and Materials Vol. 164

Abstract: The finite element ANSYS/LS-DYNA was applied to simulate the propagation characteristics of stress waves in laser shock processing (LSP) for DD6 single crystal alloy materials. The constitutive model of dynamic response and computational modeling of LSP was built in this paper. Results of numerical simulation indicates that the change of stress waves was mainly appeared to the first wave, and the time with fluctuation was expanded slowly with the spread depth of stress wave was increased. The results can be used as theoretical basis for optimizing the process parameters in laser shock processing.

Abstract: Steel is a kind of important material. The accurate control about the end temperature of molten steel has significant impact on the quality of steel material. Case Based Reasoning (CBR) is used to predict the end temperature of molten steel in Argon Oxygen Decarburization (AOD). Grey Relational Degree (GRD) with different weights of attributes is adopted to calculate the similarity between cases. Analytic Hierarchy Process (AHP) is taken to determine the weights of attributes. Multiple Linear Regression (MLR) is applied to compute the relative weight of two different attributes for AHP. Two methods, CBR using AHP with Equal Weights (CBR_AHP_EW) and CBR using AHP with Different Weights (CBR_AHP_DW), are employed to for a comparison. The results show that CBR_AHP_DW is effective in predicting the end temperature of molten steel in AOD and CBR_AHP_DW outperforms CBR_AHP_EW.

Abstract: The effect of organic modification on the surface of silicon nitride powders has been investigated. The Si₃N₄ powder modified by tartaric acid and PEI was characterized by using granulometer, X-ray diffraction, thermogravimetric analysis, diffuse reflectance infrared Fourier transform spectroscopy, SEM. The results show that modifier on Si₃N₄ powder surface is chemical adsorption coating. The addition of modifier dose not change phase, but modified particles have spherical tendency. Modifier coating occurred oxidative decomposition in 200-400°C. surface modification can improve the fluidity of powder and density of green bodies. As the amount of modifier increased, the angle of repose and compression degree firstly decreases and then increases. The angle of repose of artaric acid and PEI modified powder decrease 9 º and 12º, compression degree decline 15% and 20% respectively.

Abstract: We synthesized carbon-coated iron magnetic nanoparticles by a low cost method using Ferric nitrate as the iron precursor and starch as both reductive agent and carbon source under H2 atmosphere. The structure, size distribution, phase composition, magnetic properties and oxidation resistance of the particles were investigated by transmission electron microscopy, X-ray diffraction, vibrating sample magnetometry and differential scanning calorimetry. The results show that the carbon-coated iron nanoparticles are spherical particles with a diameter of 20-40 nm. They are particles of core-shell structure with an iron core inside and an onion skin carbon layer outside, carbon layer can protect inner iron core from been oxidized, the hysteresis curves show that they are super paramagnetic materials. At the same time the annealing can change the magnetic properties of carbon coated iron nanoparticles.

Abstract: AlCl₃ was used as catalyst in the reaction. The reaction kinetics of aluminum and isopropanol was investigated in this paper. Metallograph showed that the surface of the aluminum bar had corrosive pitting. The reaction was zero order reaction when aluminum was overdosed. Reaction order was 0.75 when isopropanol was overdosed. Finally, catalytic mechanism of AlCl₃ was investigated and the reaction of corrosive pitting was the same as that in microbattery.

Abstract: This paper is mainly focused on the structure characteristics and the flaws of existing studies of CRC+AC composite pavement, mechanics theory and finite element method are applied to establish CRC+AC composite pavement finite element models based on crack pattern, the critical load position of CRC+AC composite pavement is found out under different crack spacing, and cracks on the AC layer extended mechanisms have been studied. The results show that: critical load position may appear in the horizontal cracks in the middle of the edge and vertical of the central free edge; in the long-term effect of traffic load, AC layer surface because of traffic loads, temperature effects, quality of construction, materials, aging and other factors produce longitudinal and transverse cracking. CRC layer transverse cracks in the bottom layers of the corresponding region AC will also have cracks, and finally forms reflective crack on the AC layer surface.The results can provide a basis for rational design of CRC+AC composite pavement.

Abstract: In order to widely use Eucalyptus urophydis wood, its ether/acetone extractives were identified by Py-GC/MS. The main and abundant constituents of 750°С pyrolysis products were 1,3-butadiene, 2-methyl-(5.9%), benzofuran, 2,3-dihydro-(4.11%), 1,3-butadiene(3.69%), stigmastan-3,5-diene (3.66%),.gamma.-sitosterol(2.13%), 2-butene, 2,3-dimethyl-(2.03%), toluene (1.92%), 1,4- cyclohexadiene,1-methyl-(1.76%), 1h-indene, 5-butyl-6-hexyloctahydro-(1.73%), 1,3-cyclohexadiene(1.66%), phenol(1.58%), 1-hexene(1.54%), sulfide, bis(2-cyano-3,4- dihydro- 2,3,3-trimethyl-2h-pyrrol-5-yl)- (1.46%), benzene(1.38%), phenol, 4-methyl-(1.35%), cholest-8(14)- ene-3,15-dione(1.23%), acetic acid(1.21%), benzene, 1,2,4-trimethyl-(1.2%), stigmast-4-en-3-one (1.12%), 1-decene(1.1%), 1-heptene(1.08%),etc. So the ether/acetone extractives of Eucalyptus urophydis biomass were used as biomass energy.

Abstract: The polyaspartic acid (PASP) composite was prepared from PASP , sodium gluconate , zinc sulfate , sodium tungstate and phosphate .The corrosion inhibition performance of PASP composite on A3 carbon steel in seawater was studied by using steady polarization. The results showed that PASP composite had good corrosion inhibition performance in seawater . When the concentration of PASP composite was 300 mg/L , the corrosion inhibition rate reached 79.25% .

Abstract: Manufacture process parameters will be obtained from experiments in research. Molding technology determines the mechanical properties and performance of the product. The influence of molding temperature and time are significant on the performance of water lubricated bearing, the plastic alloy is based on latex material, synthesized with different fillings, accelerators and other matters, and displays great mechanical and friction properties. The main performance included peel strength, tensile strength and wearing capacity. Optimization of manufacture process parameters and the orthogonal experiments on them were carried out by integrating the results of experiments and finally the optimal manufacture process was achieved. In the experiment, three-leveled orthogonal tests were conducted for the three systems to test the tensile strength, tearing strength, stress at definite elongation, hardness and tensile rate. The impacts of the respective systems were analyzed and the content of each component are determined to get the optimal formula.