Key Engineering Materials Vols. 334-335

Abstract: Liquid Composite Moulding (LCM) processes are commonly used techniques for the manufacture of advanced composite structures. This study explores the potential of wood fibres as reinforcement for LCM preforms, considering mats produced using dry and wet methods. The compaction response of these mats has been investigated with and without the presence of a test fluid. Permeability of these mats was also measured as a function of fibre volume fraction. Reinforcement permeability and compaction response data were used to model two different LCM processes. The simulation results have been compared with experiments.

Abstract: The maximum number of carbon atoms adsorbed at edge dislocation was calculated using a model based on Boltzmann distribution. The number of carbon atoms adsorbed by edge dislocation increases with bulk concentration increasing and temperature decreasing. When the interfacial energy was chosen as 0.2J/mol, the maximum radius of carbon depleted zone is smaller than the critical radius required for displacive nucleation at 700K, however, larger than the critical radius at 600K. Moreover, the radius of carbon depleted zone around the dislocation at 600K is larger than that at 700K. It seems that bainite may nucleate by a displacive mechanism at lower temperature.

Abstract: The properties, performance, and reliability of a cermet material depend mostly on the intrinsic properties influenced by microstructure that evolves during processing and use. In this study, the effect of microstructure on reliability of multiphase materials in erosive media is analyzed with reference to WC-, TiC-, and Cr3C2 - based ceramic-metal composites. Microstructure of multiphase materials, fracture mechanisms, ability of energy dissipation, thermo-mechanical parameters and erosion resistance are examined. It has been shown that microstructural variables play a very important role in cermets performance. The energetic criterion of non-homogeneous materials selection has been presented.

Abstract: This presentation will illustrate the history, current status and future development of composite and FRP industry in Taiwan. This paper will present the characteristics of composites industry in Taiwan. The statistic survey of market and products of composite will be shown in details. Trend and development of FRP and Composites will be discussed. Unique products made in Taiwan will be described by several categories. The challenge and prospective aspects of Composite Industry will be discussed. Research and Development of Composite in Taiwan are critical to our industry which will be emphasized. International cooperation has been conducted which will be presented. Emphasis will be placed on the R&D of composites in Taiwan including: Basic research. Processing. Nanocomposites. “Green composites” and High-tech applications. Academia-industry cooperation will be discussed. International cooperation among academic institute, society/association and foreign industry will also be illustrated.

Abstract: This paper demonstrates the use of ultrasound (US) indentation technique for estimating the mechanical properties of tissue- mimicking phantom composites. A tissue-mimicking phantom composite is used to simulate two-layer soft tissue in human. Investigation on the mechanical properties of the phantom composites is extremely important for the understanding of the viscoelastic behaviours of soft tissues and the validation of our proposed US indentation system. The hand-held indentation probe embedded with a US transducer and a load cell together with a US pulser/ receiver. The output of the whole indentation process can be illustrated as force-deformation curves. The mechanical properties of the phantom composites can be estimated by analyzing the force-deformation curves using genetic algorithm (GA).

Abstract: An analytical model was established by means of Ritz method to calculate the cured shape of cross-ply unsymmetric composite laminates. A number of experiments of Carbon/Epoxy laminates were conducted. It was found in the experiment that the warped surface could be a multiple-value function, which should be studied further. The result of calculation correlates well with the experimental result except the regions very near the laminate edge. The conclusion is instructive to manufacture of composite laminates.

Abstract: The dynamic stress intensity factor was studied about the Griffith crack between the visco-elastic layer and elastic body under shear loading. Adopting integral transform and singular integral equation method, the time response of dynamic stress intensity factor was calculated. Considering the influence of materials parameter, it was found that the dynamic stress intensity factor increases with crack length increasing, and it posses distinct size effect when the thickness of visco-elastic layer reaching the character size of materials.

Abstract: A series of carbon fiber reinforced C-SiC dual matrix composites (C/C-SiC composites) were developed through precursor infiltration of polycarbosilane (PCS) and pyrolysis (PIP), using porous C/C composites with different density from chemical vapor infiltration (CVI) as the preform. The density, mechanical properties, and microstructure of the composites were investigated and the effects of the preform density and the PCS concentration of the infiltration solution on the final density and the mechanical properties of the composites were discussed in detail. The results show that the final density of the C/C-SiC composites prepared at the infiltration concentration of 50% is the highest, indicating that 50% is the proper PCS concentration of the PCS/ Xylene solution to prepare the C/C-SiC composites. The final densities of C/C-SiC composites were closely related to the preform density and the highest final density corresponds to the highest original preform density. For the composites prepared using infiltration solution of 50% PCS, the C/C-SiC composite whose preform density is 1.23 g/cm3 possesses the best mechanical properties while that whose preform density is 1.49 g/cm3 the worst mechanical properties.

Abstract: Sodium superionic conductor, NASICON ceramic (Na1+xZr2SixP3-xO12, x=2), was hot-press sintered under different temperatures and the electrical properties of the obtained different samples were investigated. Results show that the relative density of the ceramics can be improved by hot-press process efficiently and the crystal size of the samples are closely related to sintering temperature. With the increase of sintering temperature, both the density and the crystal size of samples increase obviously, resulting in the increase of ionic conductivity of samples as the sintering temperature. When the sintering temperature reaches 1150oC, the ionic conductivity of sample is as high is 3.6×10-3S/cm, which is obviously higher than that of sample sintered at 1000oC (2.13×10-3S/cm). As the frequency increase, the real parts and the imaginary parts of complex dielectric constants for all the samples decrease in 8.2 GHz~12.4GHz frequency band. The ceramics obtained at the higher temperature possess the higher dielectric constant.