Advanced Materials Research Vols. 194-196

Abstract: In this paper, the influence of hydrothermal environment on the composite laminate plate with a hole is studied by experiment method. The test setup is design for prevent the bucking of the plate specimen, which is composed two main parts. The slide part limits the movement of the specimen along the load direction. Three types of ply stack composite laminate plate are tested. Results show that the strength of all the type of laminate plate in the hydrothermal environment reduces on the contrast to the room temperature and dry environment. But the reduction relatives the ply stack of laminate plate. [45/0/-45/90]_2S plate reduces smallest. [45/0/0₂/45/90/-45/0/45/902/-45/0]_S plate reduces most.

Abstract: A method based on laminate theory is presented for estimating three-dimensional effective elastic moduli of multidirectional filament-wound fibre-reinforced composite thin-wall tube with lining. The effective elastic moduli of glass fibre wound tube with lining are calculated. In contrast with finite element analysis, effective elastic moduli estimated by this method are accurate.

Abstract: Cu-Fe sintered material is prepared by PM technique, and the effect of Fe content on friction property of material and the relation between Fe content and the shape of the third body are investivaged by a constant speed friction test machine. The result indicates that as Fe content in the material increased, material density and porosity haven’t changed much, while material hardness obviously increased. When Fe content is about 20%, friction and wear properties are better because the optimum amount of Fe has the function of strengthening matrix. As friction speed increased, friction coefficient reduced; the cause lies in the fact that surface temperature rise reduces the density of Cu matrix and reduces mechanical meshing drag between micro-convex bodies due to poor thermal conductance of Fe. Simultaneously, due to friction alternating stress, rigid and fragile third body with advanced oxidization generates micro cracks, and the micro cracks continuously expand, and finally drop off; thus, the wear rate is increased.

Abstract: Al-pillared montmorillonite (Al-PILM) prepared with Keggin ions was studied by means of XRD, SEM-EDS and N₂ adsorption-desorption isotherms.The rusults show that, compared to unpillared Na-montmorillonite (Na-M), the interlayer spacing d₍₀₀₁₎ value, BET specific surface area, surface fractal dimension and the proportion of microporous specific surface area of Al-PILM are larger and the surface is relatively rough. The BJH porous volume distribution of Al-PILM is the most probable distribution, and the most probable pore size is about 2 nm, belonging to mesopore. The porous structure of Al-PILM is characterized as parallel plate slit or “house-of-cards” wedge-shaped pore which is formed by novel meso-microporous delaminated structure and fragments. Besides, the results of elemental distribution show that the ions exchange action between Na⁺ and hydroxy-Al cations in pillaring solution occurs in the formation of Al-PILM.

Abstract: Ramie fibers were incorporated into polypropylene as the reinforcement fillers. The transesterification between the hydroxyl groups of ramie fiber and the ester of maleic anhydride was employed to improve the compatibility of ramie fibers and the polypropylene matrix. The morphology of the composite surfaces and interfaces were studied using IR and SEM. The mechanical properties and water absorption of the composites were investigated. The results demonstrated that the esterification occurred on the surface of ramie fiber, due to which the compatibility between fiber and matrix treated was greatly improved. Because of the improved compatibility, the mechanical strength of the composites increased; while water absorption decreased.

Abstract: Molten caprolactam momomers (<1pa•s) mixed with ABS resin and rubber-compatible agent, which is impregnated with carbon fibers (50% by volume), are adopted to prepare ABS modified nylon composite material through die formation at the 160°C polymerization temperature of anions. The analysis shows that with the addition of ABS resin and rubber-compatible agent, the mechanical properties of the material is reduced, but the amplitude of reduction is very small, and its elongation is improved by up to 1.78%; with the addition of ABS, the water absorption is reduced below 0.8%, remarkably improved compared to the like nylon base composite material; and the microscopic analysis shows that the fibers have good bonding performance with resin interface, and the addition of ABS resin does not influence the bonding performance of the interface.

Abstract: The effects of Fe doping on the structure, electronic transport properties and Raman spectra of GdBa₂Cu_3-xFe_xO_7-δ (x = 0.00-0.30) systems have been investigated. The analysis of X-ray diffraction patterns shows that the compound undergoes an Orthorhombic–Tetragonal (O-T) phase transition in the doping range of x = 0.05-0.10. The superconducting transition temperature Tc decreases with the increase of Fe doping level, whereas the superconducting transition width increases abruptly with O-T transition. We have discussed the Raman shifts and intensity of the five normal phonon peaks and some other peaks which result from the vibration of Cu(1) and O(1) oxygen for the Fe doped-samples. These investigations reveal that the electronic transport properties and Raman spectra of GdBa₂Cu_3-xFe_xO_7-δ composites obviously depend on O-T transition induced by the Fe doping.

Abstract: A novel stitching reinforcement method is applied to the laminates with cut-out for a decrease in the interlaminar stresses . The stitching parameters, such as the distance between edge and stitch line, the thread radius, and the stitch step etc.,are designed,and the three-dimentional models are established for FEM (Finite Element Method). The maximum circumferential shear stress appears in laminates of 0/-45, showing stress distribution similar to analytic solutions . The interlaminar circumferential shear stress of stitched is significantly decreased, and the validity of this method is proved.

Abstract: A full-scale experimental study on the axial behavior of cold-formed thin-walled steel framing wall studs is presented. The influence of parameters, including whether the studs are sheathed or not, sheathing materials, the screws spacing and the studs spacing, on the bearing capacity of studs under vertical compression is analyzed by the test. The test results of the six wall specimens show that: the load carrying capacity of a stud increases significantly when it is covered with sheathings; the ultimate load of the stud sheathed with fiber reinforced calcium silicate board(CSB) is about 18.8 percent higher than that sheathed with oriented strand board(OSB); when the wall frames are sheathed with OSB or plasterboard, the change of screws spacing has little effect on the bearing capacity, however, the bearing capacity of CSB-sheathed wall stud will fall when the screws spacing decreases from 300mm to 150mm; when the studs spacing increases, the bearing capacity of stud decreases slightly.

Abstract: In this paper, bentonite was applied in mango preservation, and the effects of various treatments methods on fresh-cut mango were studied.The results indicated that mangoes without any treatment easily rotted. The quality indexes of mango such as the weight loss rate, the disease rate and the turning yellow rate tend to increase while the titratable acidity and vitamin C content of mango lose largely. However, the weight loss rate, the disease rate and the turning yellow rate of mango may be reduced when mango were packed in seal bags together with bentonite. Purified bentonite is better than raw bentonite when applied in keeping mango fresh. Burying mango in mass purified bentonite was advisable for mango preservation.