Advanced Materials Research Vols. 415-417

Abstract: Nowadays, the demands of large scale surface devices are becoming popular in engineering fields. The grinding process is one of the common methods to achieve the high quality of large scale workpiece. But the final form accuracy of large scale devices is always low. Then it is necessary to analyze the error mechanism of grinding machine on the form accuracy of large scale workpiece. In this paper, the influencing factors of surface grinding machine with horizontal spindle and rectangular table were analyzed firstly. Then the mechanism of guiding accuracy on the surface form accuracy was discussed. It is found that the Z-axis’ guiding accuracy could seriously influence the surface form accuracy. Finally, the face grinding experiment of large scale iron workpiece (420mm×420mm) was performed and the surface form accuracy was measured. The experimental result was in agreement with the theoretical result. It can be concluded that the Z-axis guarding accuracy of grinding machine should be exactly controlled to achieve the high surface precision of large scale device.

Abstract: Geometric parameters of composite materials often have a random nature in engineering structures. How to study random response and statistical properties of nonlinear systems with random parameters has a very important significance for reliability and optimization of structural design. In this paper, perturbation method and random central difference method are explored to establish composite nonlinear vibration equations and computational model to study random responses of nonlinear systems with random parameters under deterministic loading of the composite laminates, numerical examples illustrate the correctness of the algorithm.

Abstract: Abstract: In this paper，2-D and 3-D fluid models are calculated using equilibrium molecular dynamics simulation, the viscous coefficient and pressure are obtained under periodic boundary. By comparing and analyzing the differences of viscous coefficient and pressure curves between 2-D and 3-D fluid models, the way for how to use 2-D model to get the accurate viscous coefficient is found, the feasibility of 2-D model is discussed.

Abstract: An accurate finite element contact analysis of helical gears was done directly under ANSYS, while the integrated elastic deformation of the meshed teeth was extracted directly from the finite element contact analysis results, and considered as the main basis of the amount of tooth profile modification. Linear, conic, cubic, and sine relief curve are compiled and established in MATLAB, on which gear models of two ways of modified gear are built. Under the same modified parameters, contact method is used on the proposed finite element models of gears by software LS-DYNA, and the effect of the two ways of gear relief on contact force on teeth face is analyzed. The results show that the effect of a pair of gears relief is better than one gear relief for linear and conic relief curve, and the effect of one gear relief is better than a pair of gears relief for cubic and sine relief curve. So dynamic simulation on modified involute gears has great significance for reducing contact force of teeth face of gears.

Abstract: In situ NbC and VC nanoparticles reinforced Fe-Si-Mn-Nb-V matrix composite was carried out using a plasma jet with a plasma gas flow of (Ar + CH₄) for very short time. The process involve improving the efficiency of the reaction in terms of consumption of the available active nitrogen atoms as well as the production of very fine and homogeneous distribution of all reinforcing phases of ceramic particles, preferable in the nanometer range. The nanoreinforcements synthesized by in situ reaction in this hybrid composite are NbC and VC ceramic particles.

Abstract: SiC coated carbon fiber-reinforced SiC matrix (C/SiC) composites were implanted with aluminum ions by metal vapor vacuum arc ion source to improve their oxidation resistance. Depth profile of the aluminum ions in the SiC coated C/SiC composites was checked by Auger electronic energy spectrum. Oxidation tests were performed in flowing dry air at 1300°C on the SiC coated C/SiC composites. The samples with ion implantation exhibited lower weight loss than those without aluminum ion implantation. The surface morphologies of the samples were obtained by scanning electronic microscope. As compared with the mechanical properties of the samples without ion implantation, those of ion-implanted samples changed little.

Abstract: The paper analyzed the pressures and the temperatures in compression chambers for calculation of bending fatigue strength , and a strength model is proposed. For the small parameter scroll wraps, the pressure loads are of π-region pressures which have a normal angle interval of π, the number of acting regions for pressure loads is equal to the number of scroll compression chamber pairs. Apart from the part situated in the center compression chamber, the temperatures of scroll wrap decrease linearly with the normal angle. Selecting the reasonable discharge, specifying the appropriate material and the parameters, and modifying the starting part of scroll wrap are significant methods to improve fatigue strength of scroll wraps in practice.

Abstract: The effects of styrene-maleic anhydride copolymer (SMA) and epoxy resin (ER) on the interfacial interaction of Acrylonitrile-butadiene-styrene terpolymer/Short glass fiber composites were investigated by means of scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), and mechanical properties. The experimental results demonstrate that SMA and ER could effectively improve interfacial interaction between the ABS and SGF. Based on SEM, good interfacial adhesion between ABS and SGF in ABS/SMA/ER/SGF and ABS/ER/SGF composites was observed. DMA results showed that SMA and ER decreased the glass transition temperature (Tg) and height of tanδ compared with ABS/SGF composites. The synergy effects of SMA and ER on the interface interaction was investigated. All results in this paper were consistent, and showed a good interaction between ABS and SGF, which was proven by the mechanical properties of the composites.

Abstract: Polyoxymethylene (POM) composites filled with low-density polyethylene (LDPE) and sisal fibers (SF) were prepared by extrusion and injection molding. Sisal fibers were treated by various concentrations of NaOH solution to improve the poor compatibility between SF and matrix. Fourier transform infrared spectroscopy (FTIR) analysis and scanning electron microscope (SEM) test were used to confirm the surface treatment. The effects of SF alkaline treatment on the mechanical and tribological properties of POM composites were determined by using tensile test, impact test and friction and wear test. The worn surfaces of composites were investigated by SEM. Results showed that the composite filled with 12.5% NaOH treated SF exhibited the optimal mechanical and tribological properties among the all composites. The major wear mechanism of the composites was adhesive wear and abrasive grain wear.

Abstract: The Mn²⁺ removing effect from groundwater by four kinds of filters——Zeolites ,Activated Carbon ,Manganese Sand and a new filter ANJ.SiC, were comparatively studied and analyzed respectively .The results show that, the Mn²⁺ removing effect of ANJ.SiC is significantly better than the other three .It is an ideal filter in Mn²⁺ removing ,which can be reused for a long time .These filters’ surface characteristics before and after saturation were compared through their SEM figures ,and the Mn²⁺ removing mechanism were further studied.