Materials Science Forum Vols. 654-656

Abstract: In construction industries, new construction materials are needed to overcome some problems associated with the use of conventional construction materials due to the change of environmental and social requirements. Accordingly, the requirements to be satisfied in the design of civil engineering structures are diversified. As a new construction material in the civil engineering industries, fiber reinforced polymeric plastic (FRP) has a superior corrosion resistance, high specific strength/stiffness, etc. Therefore, such properties can be used to mitigate the problems associated with the use of conventional construction materials. Nowadays, new types of bridge piers and marine piles are being studied for new construction. They are made of concrete filled fiber reinforced polymeric plastic tubes (CFFT). In this paper, a new type of FRP-concrete composite pile which is composed of reinforced concrete filled FRP tube (RCFFT) is proposed to improve compressive strength as well as flexural strength of an RCFFT. The load carrying capacity of proposed RCFFT is discussed based on the result of experimental and analytical investigations.

Abstract: As a new construction material, fiber reinforced polymeric plastic structural shapes are readily available. Therefore, construction and structure rehabilitation using FRP materials are an ever increasing trend because of FRP material’s superior chemical and mechanical properties compared with those of conventional construction materials such as steel and concrete. Among the FRP materials, pultruded fiber reinforced polymeric plastics are the most popular for civil engineering applications. However, it has relatively low modulus of elasticity and also cross-section of structural shapes is composed of plate components such as flange and web. Therefore, stability is an important issue in the design of pultruded structural shapes. For the design of pultruded structural member under compression, buckling and post-buckling strengths of plate components should be taken into account. In the structural steel design following AISC/ LRFD, this effect, in addition to the buckling strength, is incorporated with a form factor. In this research, the form factor for the design of pultruded structural shapes under compression is investigated. Based on the analytical study, the form factor for the design of pultruded structural shapes have been suggested.

Abstract: Three types of unsaturated polyester matrix, ortho phthalic, iso phthalic, and vinyl ester, reinforced with glass fiber laminated composite waste have been subjected to investigate thermal decomposition behavior and kinetic parameters using non-isothermal thermogravimetric analysis from an ambient to temperature 900°C under nitrogen atmosphere at the passing flow rate of 20 ml/min. The results showed that the major decomposition range of the unsaturated polyester matrix was from 260 to 445°C, depending on a heating rate and the different types of polyester matrix. Regarding their chemical structure, ortho phthalic polyester started to degrade at lower temperature (260-280°C) than iso phthalic and vinyl ester (300-350°C). The remaining solid residual contained glass fiber which could not degrade under experimental conditions. The maximum rate of weight loss was increased with increasing heating rate. The activation energy for decomposition of ortho, iso phthalic, and vinyl ester composites was 168, 172, and 176 KJ/mol, respectively.

Abstract: The performances of aluminum /vinylester particulate-composites were studied in detail in order to investigate its suitability for engineering applications. This study examined the suitability of atomised aluminum particles for particulate reinforcement of a vinyl ester resin. Mechanical properties were obtained for the composite by testing various percentages of aluminium powder (75-150 m) and vinylester resin. It has been found that the inclusion of Al powder has not significantly changed the properties of vinylester resin, however an improvement in the ductility of the composite has been recorded. The optimal performances of the composite were exhibited by 15% Al composition. The properties of the particulate composites were modeled using numerous empirical models. Unfortunately a significant difference was found between some of the experimental and predicted properties of the Al/vinylester particulate composite. This paper intends to detail the variation of mechanical properties with the change of Al volume fraction in the composite and the performances of empirical models in prediction of the properties of particulate composites.

Abstract: For the designed center frame of low-floor vehicle to have light-weight sandwich structure with glass fabric/epoxy resin skins, aluminum honeycomb cores and steel inner-frames, regression equations for maximum equivalent stresses (Von-Mises stress) and maximum vertical deflection were proposed by finite element analysis. On the basis of the analysis results, the strength and stiffness for the center frame were discussed in this paper.

Abstract: This study introduces the structural analysis and the testing results of the composite structure which is applied to tilting train in Korea. The composite structure is made of aluminum honeycomb structure materials like a sandwich. The static load test was performed to evaluate the structural characteristic and stability of the composite structure. Considering the vertical, compressive, torsional load and 3-point supporting type as a testing terms, the structural stability of a carbody was evaluated. Load test are based on "Performance Test Standard for Electrical Multiple Unit" with the reference code JIS E 7105. The test results have been very safety and stable for design load conditions.

Abstract: New technology of reinforcement materials in asphalt overlays can offer a potentially cost effective solution for treating cracked pavements. To date, however, there is no design process allowing the use of available reinforcement products in road applications in Australia; whereas overseas design procedures are not readily available. A new 3D finite element (FE) analysis procedure was considered where reinforced asphalt layer is modelled as a thin 3D compound non-homogeneous layer which is then converted into a 3D orthotropic membrane. This procedure was used to analyse performance of three reinforcing products for road applications in Australia and results indicated that it is possible to predict and compare “retard reflection cracking” performance of various reinforced products.

Abstract: This study explains the design, manufacturing and test results for a composite side beam. It has been developed to be applied to the railway bogie frame. The bogie frame is a most important component for safety of a railway vehicle. In this study, the dimensions and stacking sequence of the composite beam has been determined by parametric study and manufactured using autoclave curing. It was tested under static loading conditions of 140kN and 182kN to evaluate structural safety and stiffness. In addition, the nondestructive test using radiograph was performed to investigate the internal damage of it before and after the test.

Abstract: Copper-40mass%zinc (Cu-40Zn) brass alloy powder containing 1.0 mass% Cr was prepared by the water atomization. Graphite particles, having a mean particle size of 5 μm, were added to the as-atomized powders by the ball milling equipment for 4h under 120 rpm. Spark plasma sintering process was used to consolidate the above elemental mixed powders (sintered material). Sintered materials were heat-treated for the precipitation of much Cr (HT material). The machinability of Cu-40Zn brass alloys was evaluated by a drilling test using a drill tool under dry conditions. The matrix hardness of sintered material was higher than that of HT material. On the other hand, the machinability of sintering material was higher than that of HT material. There is no trade-off relationship between the matrix hardness and machinability of the brass alloys. SEM-EDS observation indicated that Cr content dissolved in the brass matrix of sintered material and HT one was 0.42 mass% and 0.19 mass%, respectively. As the reason why machinability of HT material lowered, the precipitation of the hard Cr particle or generation of Cr-C compound caused to inhibit the machinability.

Abstract: In this paper, BaPbO3(5Vol.%)/2024Al composite was fabricated by powder metallurgy method. Nanosized Pb particles were formed from the in-situ reaction between BaPbO3 and 2024Al, and mainly distributed homogeneously inside grains. The hot compression deformation of the composite at different temperatures was performed. The microstructure evolution of the 2024Al matrix and dynamic mechanical analysis (DMA) of the composite were made to investigate the effect of liquid Pb on the hot deformation. The results show that the presence of the liquid phase reduces deformation resistance by decreasing dislocation pileups, and simultaneous decrease in Young’s modulus of the composite.