Papers by Keyword: Mechanical Properties

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Authors: Siti Norasmah Surip, A.H. Ismail
Abstract: In this new world, polymer nanocomposites have developed to be one of the latest evolutionary steps in the polymer technology, besides showing a great deal to become the most versatile industrial advanced materials. In comparison with conventional composites, nanocomposites demonstrate significantly higher levels of mechanical performance with less content of particles. Thus, this study was carried out to investigate the effect of nano& micron size of clay particles to mechanical properties of epoxy adhesive. Three types of mechanical test were performed; tensile, impact and shear test. The result shows that the tensile strength was increase by using micron clay while shear and impact strength was increase by using nanoclay. The dispersion of clay in the epoxy adhesive is very important because it will affect the mechanical properties of epoxy adhesive itself. The function of clay to enhance the properties of epoxy adhesive is more effective when the clay is well dispersed. FESEM shows that the nanoclay was well dispersed in the epoxy adhesive while micron sized clay was partially intercalated.
Authors: Souad A.M. Al-Bat’hi, Souad A.M. AlBat’hi, Yose Fachmi Buys, Muhammad Hazwan Hadzari, Maizatulnisa Othman
Abstract: Nowadays, people have built mega-watt scales of wind turbines to generate electricity from wind energy. These big scales of wind turbine blade need lighter materials in order to optimize the generation of electricity. Due to this issue, purpose of this paper is to find a light material which is suitable to be used in making wind turbine blades. The use of natural fiber as a reinforcement agent in composite seems to have a big potential as natural fibers show desired characteristic needed for wind turbine blades' material. In this research, rice straw fiber was used as reinforced agent in composite with polypropylene as matrix. The composite produced was then characterized by mechanical testing which include tensile, flexural and impact as well as density measurement, dynamic mechanical testing (DMA) and Scanning Electron Microscopy (SEM). From the result obtained, it is found that the introduction of rice straw fiber to polypropylene matrix able improve the mechanical properties of the composite. The results of the composite obtained were then compared with current materials used.
Authors: Ming Song, Hui Wang, Tong Xu, Xue Tao Zhang, Jing Xiang, Yong Hui Sun, Bin An Shou
Abstract: A comprehensive study was carried out on the determination of mechanical parameters in the weld zone by using the digital image correlation (DIC) method. The DIC method provided quantitative two-dimensional strain maps of the deformation field across the weld joint throughout the tensile test. Then the local stress-strain response was extracted based on these strain maps on the uniform stress hypothesis. The strain distribution evolution during loading performed a good consistency with the indentation test results and the cracking position of the specimen. The deformation related parameters of local areas in weld joint were successfully extracted by DIC method. These parameters are very valuable for the structure design of the weld components, especially in the case of the structure in which the allowable stress is controlled by the deformation feature but not the strength of the material such as the high temperature applications.
Authors: Trond Furu, Rune Østhus, Jostein Søreide, Ole Runar Myhr
Abstract: The present paper describes an innovative methodology that has been developed for optimization of product properties, production costs, and environmental impact in fabrication of aluminium alloys. The main idea is to represent each operation along the process chain by predictive models, which include material, mechanical, cost, and sustainability models. A multi-objective optimization platform is used to combine the models into a common software environment, which allows fully automatic simulations. The optimization tool runs the models in iterations until user-defined acceptance levels on properties, costs, and sustainability indices are obtained. In this paper, the methodology has been applied for fabrication of 6xxx-series aluminium extrusions. As a demonstration of practical relevance, the software tool was used to optimize mechanical properties and electrical conductivity by manipulation of alloy chemistry, processing parameters, and microstructure characteristics like grain structure, precipitates, dispersoids, and solid solution concentrations. At the same time material and production costs, as well as CO2 emissions along the value chain were attempted to be kept at minimum levels.
Authors: Abdulhamid Al-Abduljabbar
Abstract: Polymer-clay nanocomposites (PCNC), are characterized by the high ratio of surface area to volume of the clay nanoparticles which are in the form of clay platelets with very high aspect ratio. This feature provides superior gas barrier properties at very low volume fraction of the nanofiller. Clay platelets introduce discontinuity to flows through the bulk polymer matrix material. The extent of this improvement depends on the success of separation of clay layers during processing which would produce single-layer particles (exfoliation) or several-layer particles (intercalation) through the bulk polymer matrix. This paper discusses the common permeability models used to capture the effects of the clay nanofillers in PCNC. Since these models assume a state of full exfoliation of clay platelets; that is a single phase of the nanofiller, they fall short of representing the actual state as evidenced by experimental works, which confirm the presence of both the intercalated phase and the exfoliated phase. A model that incorporates clay inclusions with different sizes (different thicknesses) is proposed and its implications are assessed.
Authors: Yao Xiong, Jian Yin
Abstract: Aggregate-mortar interface transition zone is a major factor for mechanical properties and durability of materials. Owing to the distinctive features of interface transition zone, this study reviewed research methods, structure models, improving methods and the influence to mechanics and durability of concrete of this zone. We also analyzed various test methods which are referred to in this review and their applicability, and discussed the formation mechanism and improving approach for interface transition zone. Our investigation suggested further scientific test is necessary for researching mechanical property of the interface.
Authors: Anuj Singh Baghel, Ankur Tiwari, R.S. Rana, Vilas Warudkar
Abstract: Aluminium, being the second most abundant metal in earth’s crust, has emerged as an important metal in human civilization’s development. It has served as an excellent substitute for many conventional materials like wood, copper, iron and steel. Now a days, more Aluminium is consumed (on a volumetric basis) than all other non-ferrous metals/alloys including copper.Aluminium and aluminium alloy are gaining huge industrial significance because of their good combination of mechanical, physical properties over the base alloy. In some few recent years the use of metal matrix composite material increases very rapidly due to their high weight to strength ratio, low density, low thermal expansion coefficient, low maintenance and high temperature resistance. Metal matrix composites are widely used in aerospace and automotive engine components. The aluminum alloys are reinforced with Al2O3, B4C and TiC and fabricated by stir casting, centrifugal casting, and powder metallurgy process. In the fabricated metal matrix composites some different tests were conducted to show mechanical properties, micro-structural characterizations of materials were also done. When composite subjected to heat treatments then it significantly affects the micro-structural developments of composite causing to relieving of stress.
Authors: Jana Zahálková, Pavla Rovnaníková
Abstract: The production of Portland cement is connected with high emissions of greenhouse gases, especially carbon dioxide, and the intensive consumption of energy and natural resources. The present trend is for the replacement of cement by reactive admixtures, which can include ground waste glass, a material which shows pozzolanic activity. This paper deals with the determination of the mechanical properties of cement pastes in which part of the cement mixture (5 to 30 %) was replaced by borosilicate glass. The process by which the hydration of the cement with ground glass began was monitored by an isothermal calorimeter.
Authors: C.S. Suhas Kowshik, Pavan Hiremath, Manjunath Shettar, Nithesh Naik
Abstract: In this study, hybrid composites were prepared using chicken feather as filler material. Hybrid composites were tested for tensile and flexural strength. Composites were prepared by hand-layup technique by varying the weight percentage of chicken feather (0, 4, 8 wt.%). Samples were tested according to ASTM standard. SEM images were studied to find the fracture and interfacial characteristics of the composites. Results indicated that, these composites can be used in domestic, automobile and structural applications, where minimal load is applied.
Authors: Ho Sung Lee, Koo Kil No, Joon Tae Yoo, Jong Hoon Yoon
Abstract: The object of this study was to study mechanical properties of friction stir welded joints of AA2219 and AA2195. AA2219 has been used as an aerospace materials for many years primarily due to its high weldability and high specific strength in addition to the excellent cryogenic property so to be successfully used for manufacturing of cryogenic fuel tank for space launcher. Relatively new Aluminum-Lithium alloy, AA2195 provides significant saving on weight and manufacturing cost with application of friction stir welding. Friction stir welding is a solid-state joining process, which use a spinning tool to produce frictional heat in the work piece. To investigate the effect of the rotation direction of the tool, the joining was performed by switching the positions of the two dissimilar alloys. The welding parameters include the travelling speed, rotation speed and rotation direction of the tool, and the experiment was conducted under the condition that the travelling speed of the tool was 120-300 mm/min and the rotation speed of the tool was 400-800 rpm. Tensile tests were conducted to study the strength of friction stir welded joints and microhardness were measured with microstructural analysis. The results indicate the failure occurred in the relatively weaker TMAZ/HAZ interface of AA2219. The optimum process condition was obtained at the rotation speed of 600-800 rpm and the travelling speed of 180-240 mm/min.
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