Key Engineering Materials Vols. 334-335

Abstract: This paper explains the structural safety evaluation of a hybrid composite train carbody. The composite carbody with length of 23m was manufactured as a sandwich structure composed of a 40mm-thick aluminum honeycomb core and 5mm-thick woven fabric CF1263 carbon/epoxy face. In order to evaluate the structural safety of it, the dynamic force of ±0.2g was applied to the full weight carbody by two 50-ton capacity hydraulic actuators. The excitation frequency was determined by the first bending natural frequency evaluation test under full weight condition. The test was conducted for 2x106cycles. During the test, the nondestructive tests using X-ray for the composite body structure and liquid penetrant test for the welding region of the steel underframe were performed.

Abstract: The microstructure and mechanical properties of pure copper clad Aluminum wires in different diameters by drawing at room temperature were studied in this paper. The results show that the microstructure of the cladding wire by drawing at room temperature is vimineous grain as fibril shape from prime equiaxed grain. The fibril diameter is in inverse proportion to deformation and the fibril length is in direct proportion to square of deformation approximately. The ultimate tensile strength of the cladding wire by drawing at room temperature increases in direct proportion to square root of deformation, and the elongation decreases and fluctuates. Basis of the ultimate tensile strength of prime pure copper and aluminum alloy, the ultimate tensile strength of the cladding wires in different diameters can be doped out by mixed principle of composite material.

Abstract: By application of clad-bonding technique of pure copper sheet and plain low carbon steel rebar Q195, the cladding wires in different diameter by drawing at room temperature have been worked. The increasing ratio of the area of grain boundary is in direct proportion to deformation approximately. The resistivity of the cladding wires go up in direct proportion to deformation because the increment of the area of grain boundary results in increment of static disfigurement to electron dispersion. When deformation is less 9.6, the relative increment of resistivity is less 1.1%, i.e. the wire is provided with good electrical conductivity. And the resistance and resistivity of the wires can be estimeted based on copper ratio of transverse section of the cladding wire and the deformation by drawing at room temperature.

Abstract: Reaction sintering and hot-isostatic-pressing (HIP) have been used for the compaction and densification of mullite-whisker-reinforced alumina composites. The effect of alumina matrix constraints on the in-situ transformation sequence in alumina-halloysite-AlF3 system was studied using differential thermal analysis. The physical and mechanical properties of the HIPed samples have been characterized in terms of bulk density, apparent solid density, porosity, Young’s moduli, flexural strength, hardness and the fracture toughness.

Abstract: Titanium diboride (TiB2) appears to be an attractive candidate for a high-temperature fiber reinforced composites. Chemical Vapor Infiltration (CVI) has been carried out for the preparation of TiB2/C composites. Titanium diboride has been deposited from the gas mixtures of TiCl4, BCl3, and H2 in the furnace at the reaction temperatures between 850 to 950 °C and about 20 torr. Effects of infiltration parameters such as temperature, reaction time, and concentrations of BCl3 and H2 have been studied. Analyses with SEM, TGA and XPS were carried out. The amount of deposition in the preform increased with the increases of the reaction time, temperature and the flow rate of BCl3. The activation energy of the whole deposition reaction could be estimated from the Arrhenius plot.

Abstract: A shear-lag model is developed to predict the stress distributions in and around an isolated fiber in a single-fiber polymer matrix composite (PMC) subjected to uniaxial tensile loading and unloading along the fiber direction. The matrix is assumed to be an elasto-plastic material that deforms according to J2 flow theory. The stress distributions are obtained numerically and compared with a different shear-lag model that employs total strain theory as a constitutive equation of the matrix material. An effect of the difference between the models on the derived stress state is discussed.

Abstract: The study for strength calculation of one way fiber-reinforced composites and the study measuring precisely fiber orientation distribution were presented. Need the systematic study for the DB that can predict mechanical properties of composite material and fiber orientation distribution by the fiber content ratio was not constructed. Therefore, this study investigated what affect the fiber content ratio and fiber orientation distribution have on the strength of composite sheet after making Glass Mat Reinforced Thermoplastic Sheet by changing fiber orientation distribution with the fiber content ratio. The result of this study will become a guide to design data of the most suitable parts design or fiber reinforced polymeric composite sheet that uses the Glass Mat Reinforced Thermoplastic Sheet in industry part, because it was conducted in terms of developing products. It studied the effect the fiber orientation distribution has on tensile strength of Glass Mat Reinforced Thermoplastic Sheet and achieved this result below. The increasing range of the value of Glass Mat Reinforced Thermoplastic Sheet’s tensile strength in the fiber orientation direction is getting wider as the fiber content increases.

Abstract: This paper is concerned with the optimization of composite housing in a multi-spectral camera using Kriging algorithm. The effective use of Kriging on physical problems has been expanded to provide global approximations for optimization problems. There are two major strategies to improve efficiency and accuracy of approximate optimization using Kriging. These methods are performed by the stochastic process, stochastic-localization method (SLM), as the criterion to move the local domains and the design of experiment (DOE), the classical design and space-filling design. The proposed methodology is applied to the design of a Multi-Spectral Camera (MSC), as a practical example, which will provide high resolution panchromatic and multi-spectral images and is carried by a satellite designed to fulfill the need for further Earth observation and allowing scientists and communication experts to conduct potentially valuable experiments. When this composite structure is optimized, design constraints are taken for natural frequency and shear stress which should be considered in a launching environment.

Abstract: Since thermoplastic starch can not be used directly due to its poor properties in processing, thermoplastic starch /ethyl cellulose composite is prepared by blending method in this work. The effect of the composition and the structure on the properties of the composite is studied. The results indicate that glycerin is a better plasticizer in the processing of the thermoplastic starch compared to glycol. The mechanical properties of the thermoplastic starch are improved obviously after blending with ethyl cellulose. The composite exhibits comprehensive properties as the content of the ethyl cellulose is kept at 10%, which also has a reasonable cost.

Abstract: Rotational moulding (rotomoulding) is one of the fastest growing plastics manufacturing processes using linear polyethylenes dominantly as raw materials. However, due to their modest mechanical properties, rotational moulders worldwide are keen to develop stronger and stiffer materials. In the present study, an attempt was undertaken to apply the concept of microfibril reinforced composites (MFCs) for improving the material performance. Melt blended and subsequently cold drawn and undrawn linear medium density polyethylene (LMDPE) with either poly(ethylene terephthalate) or poly(ethylene naphthalate) possessing MFC structure were mixed with neat LMDPE and thereafter processed via rotational moulding. The rotomoulded samples were characterised morphologically and tested mechanically. The obtained unsatisfactory mechanical characteristics led to the subsequent morphological study which revealed some interesting phenomena for the rotomoulded products containing MFC blends.