Applied Mechanics and Materials Vol. 815

Abstract: In order to promote the efficient use of composite materials in civil engineering infrastructure, effort is being directed at the development of design criteria for composite structures. Insofar as design with regard to behavior is concerned, it is well known that a key step is to investigate the influence of geometric differences on the non-linear behavior of the panels. One possible approach is to use the validated numerical model based on the non-linear finite element analysis (FEA). The validation of the composite panel’s element using Trim-deck and Span-deck steel sheets under axial load shows that the present results have very good agreement with experimental references. The developed finite element (FE) models are found to reasonably simulate load-displacement response, stress condition, giving percentage of differences below than 15% compared to the experimental values. Trim-deck design provides better axial resistance than Span-deck. More concrete in between due to larger area of contact is the factor that contributes to its resistance.

Abstract: Effects of different particle sizes of recycled nitrile glove (rNBRg) on curing characteristics and physical properties of natural rubber/styrene butadiene rubber/recycled nitrile glove (NR/SBR/rNBRg) blends were studied. The particle sizes of rNBRg were differentiated by the method of producing. S1 was obtained by cutting the rNBRg (whole glove) into smaller sheet; S2 was obtained by passing rNBRg through 2 rolls mill for 10 times; S3 was obtained by passing rNBRg through 2 rolls mill for 10 times and then mechanically grinded. NR/SBR/rNBRg blends were prepared at 50/30/20 composition using two roll mill at room temperature, with different particle sizes, rNBRg (S1), rNBRg (S2) and rNBRg (S3). Scorch time, cure time, minimum torque, maximum torque, crosslink density and hardness of the blends were examined. Results indicated that scorch time, cure time and minimum torque decreased as the rNBRg particle size decreased, while maximum torque and crosslink density increased. The rigidity of NR/SBR/rNBRg blends increased when smaller rNBRg particles were used, which explained the increased in hardness and decreased in resilience of the blends.

Abstract: The using of Trans-Polyoctylene Rubber (TOR) as a compatibilizer with acrylonitrile butadiene rubber/recycled natural latex gloves (NBR/NRL-G) has been investigated. The compounds were prepared with different (TOR) loading (0, 2, 4,6 and 8 Phr) using two roll mills at room temperature. The properties such as cure characteristics, tensile properties, physical properties and morphology were studied. The compatibilized (NBR/NRL-G) compounds exhibited overall good cure characteristics, morphological and physical properties compared uncompatibilized (NBR/NRL-G) compound. The addition of the (TOR) up to 6 Phr was the optimum tensile strength.

Abstract: The effect of Al addition on the microstructure, melting point and microhardness of SnCu-Al lead-free solder alloys were investigated with two different compositions of Al which were 1 wt% and 5 wt%. These solder alloys were fabricated through powder metallurgy (PM) method. The results showed that the melting point and the microhardness value of the SnCu-Al lead-free solder alloy were increased as the Al content increased from 1 wt% to 5 wt%. The grain growth of SnCu-Al lead-free solder alloy also tends to be retarded due to the homogenous distribution of Al at the grain boundaries.

Abstract: The purpose of this study was to determine the effect of treated Cyperus Odoratus (CY) with sodium hydroxide (NaOH) on the properties of biodegradable plastics made from linear low density polyethylene (LLDPE)/CY blends. Alkali treatments for natural fibers can increased adhesion between the hydrophilic fibers and hydrophobic matric. After CY was treated with 5% NaOH solution, it can be seen that the tensile strength and Young’s modulus of the LLDPE/CY blends significantly increased. Therefore, alkali treatments can be considered in modifying the properties of natural fibers.

Abstract: Rigid polyurethane (PU) foams were prepared with palm oil based polyols (POP) and methylene diphenyl diisocyanate (MDI) in order to archieve rigid formulations. The effect of the different amount of MDI (1 wt.%, 1.1 wt.% and 2 wt.%) were studied in density, compressive strength and energy absorption. It was found that the higher compressive strength of the PU foams showed at 1.604 MPa whereas the amount of MDI increased to 1.1 wt. %. The increased amount of MDI to 2 wt.% showed the higher value in density (0.0531 kg/m³) and energy absorption with 46.490 J for 70 % displacement.

Abstract: In the present work the effect of heat treatment on the hardness behavior of AZ91 and AZ91 reinforced carbon nanotube were investigated under FESEM, Xrd and Rockwell hardness tester. Cnt was embedded homogenously into the matrix due to successfully mechanical alloying using planetary milling. Kinetic precipitation of β-phase (Mg₁₇Al₁₂) also reveal in the X-ray diffraction pattern. Meanwhile, the artificial aged nanocomposite found decreased in hardness, compare to monolithic has higher value form early aged until 36 hours aging.

Abstract: Waste tyre caused disposal problem in country all over the world. A lot of research has been done to make use of recycled tyre rubber to minimize waste tyre disposal problem. Recycled tyre rubber has been widely used for civil engineering application such as lightweight concrete and asphalt pavement. However only a few study focused on the development of material using recycled tyre rubber as drainage material for geotechnical purposes. This paper presents the experimental on properties of cement-based material consisting recycled tyre rubber. Specimens were prepared by incorporating different percentage of shredded rubber tyre with mortar. Summation of ten (10) mixes has been investigated to determine the compressive strength, density, porosity and water absorption. From the results, it is concluded that the higher percentage of shredded tyre rubber used, will decreased the compressive strength and increased the porosity and of the material.

Abstract: The aim of this study was to investigate the effects of covalent and ionic cross-linked reactions which were respectively done by using genipin and tripolyphosphate (tpp), on the structure and mechanical properties of chitosan film. Both cross-linked and uncross-linked films were prepared by solution casting method and characterized. FTIR spectra showed no characteristic of –OCH₃ peak from genipin at 1444 cm^-1 which resulted by a new covalent bonding in chitosan film. Reduction in absorption intensity at 1560 cm^-1 wave number in chitosan cross-linked tpp films were due to the presence of ionic interaction between the positive charged of amino group in chitosan and negatively charged of phosphate group by tpp. The pattern area from the XRD results showed that the covalent cross-linked had significantly changed on the chitosan`s degree of crystallinity. The water contact angle on the surface of covalent/ionic cross-linked chitosan film reached the highest θ at 82.72° which indicated more hydrophobic properties was formed. Covalent/ionic cross-linked chitosan also showed the higher mechanical strength with average tensile stress value at 71.25 MPa. All finding results demonstrated that cross-linked modification on the chitosan film had successfully reduced the film’s hydrophilicity and increased the mechanical properties of the film.

Abstract: In this study, the effect of composition on solid state sintering of tungsten-brass was carried out. The densification of W-Cu has been a difficult problem to the materials engineers. However, the densification behaviour of tungsten-brass in the solid and liquid state is still not known. Tungsten-brass with the composition of 50W-brass, 60W-brass, 70W-brass and 80W-brass were sintered in a horizontal tube furnace under pure hydrogen environment at the temperature of 900°C and the relative sintered density, hardness, electrical conductivity and microstructural characterization was carried out. The relative sintered density and the electrical conductivity increase with the increase in the volume fraction of the matrix (brass) while the hardness decreases with the increase in the volume fraction of brass. The sample with the lowest volume fraction of W has the highest relative sintered density (71%) while the one with the highest volume fraction of W has the lowest relative sintered density (66%). The microstructure of the samples was not homogeneous due to mutual immiscibility between W and brass and lack of capillary force to enhance rearrangement and distribution of W and brass. It is obvious from the results that solid state sintering cannot give full densification of tungsten-brass composites.