Applied Mechanics and Materials Vol. 749

Abstract: In this study, the PET/nylon/PET wrapped yarns are made by applying a double warp yarn process. The wrap materials are moisture transferring polyester (PET) yarns and antibacterial nylon yarns, while the core is PET yarns. Such wrapped yarns are made into moisture transferring/antibacterial knits, after which their mechanical properties, antibacterial activity, and water absorbency are evaluated. The test results show that the knits that are composed of wrapped yarns with a wrapping number being 10 turns/cm demonstrate optimal mechanical properties, antibacterial activity, and water absorbency.

Abstract: With increase of life quality, demand for surrounding environment becomes more and more severely. Noise pollution in daily life lowers comfortablility and quiet of life. It is reduced accordingly if effective utilization of sound absorbing materials. This study uses polyester (PET) fibers and Nylon fibers bended with PP fibers respectively to form PET/PP and Nylon/PP nonwoven fabrics and then thermally bonded preparing PET/PP and Nylon/PP composites. The optimal parameters are evaluated by mechanical strength, and sound absorption tests. This study expects to prepare sound-absorbing composites in application of automotive interior and indoor building wall. Nylon/PP composites prepared in this study have the optimum sound absorption coefficient of 0.4 at high frequency, when containing 10 wt% proportions of PP fibers.

Abstract: In this study, high density polyethylene (HDPE) is reinforced by the combination of clay to form HDPE/clay composites by applying maleic anhydride grafted polyethylene (PE-g-MA) as a compatibilizer and a melt compounding method. The properties of composites are evaluated with a tensile strength test, a scanning electron microscope (SEM), and a differential scanning calorimetry (DSC). Next, such composites are laminated with glass fiber woven fabrics (GFW) to form HDPE/clay/GFW composites by using a thermal compression molding method. A tensile strength test and an SEM are used to measure the properties of the HDPE/clay/GFW composites. The test results show that the combination of clay in HDPE/clay composites does not provide their tensile strength with a distinct reinforcement. However, the dispersion of clay promotes the crystallization temperature of the HDPE/clay composites. In addition, using PE-g-MA as the compatibilizer results in a good adhesion of HDPE/clay composites to GFW, which in turn augments the tensile strength of the HDPE/clay/GFW composites.

Abstract: This study uses carbon fiber (CF) and glass fiber (GF) as reinforcement for polylactic acid (PLA) fiber, and their mixtures are melt-blended into PLA/CF/GF composites. Mechanical properties of the composites are evaluated by applying a tensile test, a flexural test, and an impact test, and the dispersion of fibers is observed by using a scanning electron microscopy (SEM). The test results show that the increasing content of CF results in a greater strength in the composites while the increasing content of GF provides the composites with greater modulus. The combination of both CF and GF contributes to a certain level of mechanical strength and also decreases the production costs for the composites.

Abstract: This study uses 0.08mm copper wire and nickel-coated copper wire as the core and 75 D far infrared filament as the wrapped material to manufacture Cu/FIR-PET wrapped yarn, Ni-Cu/FIR-PET wrapped yarn and Ni-Cu/Cu/FIR-PET wrapped yarn. The three optimum metallic/FIR-PET wrapped yarns are then weaving into Cu/FIR-PET woven fabrics, Ni-Cu/FIR-PET woven fabrics and Ni-Cu/Cu/FIR-PET woven fabrics. Tensile property of metallic/FIR-PET wrapped yarns, electrical resistance of metallic/FIR-PET wrapped yarns, surface resistivity of metallic/FIR-PET woven fabrics and electromagnetic shielding effectiveness of metallic/FIR-PET woven fabric are discussed. According to the results, the optimum tenacity and elongation are chosen as 7 turns/ cm, electrical resistance of Ni-Cu/Cu/FIR-PET wrapped presents the best value, Cu/FIR-PET woven fabric has the lowest surface resistivity and Ni-Cu/Cu/FIR-PET woven fabric shows the best EMSE at 37.61 dB when the laminating-layer number is double layer and laminating at 90 ̊. In this study, three kinds of metallic/FIR-PET woven fabrics are successfully manufactured and looking forward to applying on industrial domains.

Abstract: As technology expands rapidly, scientific productions have become an indispensable part for human daily life. Hence, human begin to value environment comfort and functional property. This study purposes to add reinforcing materials, carbon fiber and glass fiber, into polyurethane (PU) foam solvent, and to form PU foam composite board after foaming and curing process. The foaming density and reinforcing fiber were altered during process. The burst strength, acoustic absorption and thermal conductivity of resulting organic/inorganic fiber-reinforced PU composite foam boards were evaluated. Result displays that, 5 wt% additions of carbon fibers improved burst strength and thermal insulation, and maintained the original acoustic absorbing characteristic.

Abstract: Logistics industry becomes the mainstream with promotion of life quality. The selection of delivery type and aging is subjected to limitations of packaging materials. In order to protect from product’s damage, this study purposes to use recycled high-strength fibers, including high-strength PET fiber, and Kevlar fibers, and thermal bonding PET fiber as well as glass fabric forming needle-punched 3D composite. For comparison of varying reinforcement on mechanical property, thermal bonding and water polyurethane impregnation are used to reinforce the 3D composite which is composed of nonwoven fabrics and glass fabrics. Result shows that, mechanical property from water polyurethane impregnation displayed much higher than that from thermal bonding. Thermal bonding remarkably improved burst strength and static puncture resistance. Therefore, 3D composite impregnated with water polyurethane reaches higher puncture protection level.

Abstract: Geotextiles are made of polymers, and their conjunction with different processes and materials can provide geotextiles with desirable characteristics and functions, such as filtration, separation, and drainage, and thereby meets the environmental requirements. Chemical resistant and mechanical strong polymers, including polyester (PET) and polypropylene (PP), are thus used to prolong the service life of the products made by such materials. This study proposes highly air permeable geotextiles that are made with different thicknesses and various needle punching speeds, and the influences of these two variables over the pore structure and mechanical properties are then examined. PET fibers, PP fibers, and recycled Kevlar fibers are blended, followed by being needle punched with differing spaces and speeds to form geotextiles with various thicknesses and porosities. The textiles are then evaluated for their mechanical strength and porosity. The test results show that a thickness of 4.5 cm and 1.5 cm demonstrate an influence on the tensile strength of the geotextiles, which is ascribed to the webs that are incompletely needle punched. However, the excessive needle punching speed corresponding to a thickness of 0.2 cm results in a decrease in tensile strength, but there is also an increase in the porosity of the geotextiles.

Abstract: In this study the experiment used the two kinds of fibers, respectively are the recycled far-infrared polyethylene terephthalate (RFPET) fibers and the low melting temperature polyethylene terephthalate (LPET) fibers. Needle punching and compare with laminated in different layers, through hot pressing to make the fabric thin, observation and testing , surface observation, air permeability test, stiffness test, and far infrared emissivity test. The study shows the far-infrared radiation rate and will not increase because of the laminate, but is a relationship with a thickness comparison.

Abstract: Damage behavior of carbon fiber-reinforced plastic composite (CFRP) under the tensile loading was investigated. Four lay-up sequences were considered: [0^o]₄, [90^o]₄, [0^o/90^o]₂, and [0^o/45^o/90^o/-45^o]. Experimental results showed that the specimen [0^o]₄ showed highest stiffness and strength followed by [0^o/90^o]₂ , [0^o/45^o/90^o/-45^o], and [90^o]₄. The behavior was analyzed by finite element method. Progressive damage model Hashin’s damage initiation criteria and energy based damage evolution law were applied. It was shown that FEA results quite well agree with experimental results. The fracture strength was strongly dependent on the failure of the 0^o directional ply.