Papers by Keyword: Impact Strength

Abstract: Now- a- days the polymers are frequently used in domestic and industrial purposes. The properties of polymer composites are somewhat inferior and may be improved with the addition of filler and fiber materials. Jute is one of most economical natural fibres and is obtained primarily from plant materials such as cellulose and Lignin. Sisal is a vegetable, natural, fully biodegradable fibre and which has good specific strength and stiffness and is used for making ropes and twines. The banana fibre is the strongest natural fibres and is made from the stem of the banana tree which. exhibits good tensile strength and incredibly durable and bio-degradable. An attempt is made to improve the properties of polymer composites using jute, sisal and banana fibers and addition of 2 % titanium di boride as filler material. The polymer composites were made by hand layup method with epoxy as matrix material. The mechanical properties of fabricated composites such as tensile and impact strength, hardness were evaluated as per ASTM standards. It is found that tensile strength, hardness and impact strength were improved with the addition of fibers and filler material. The micro structural evaluation is also carried out using scanning electron microscope and found that particles were dispersed in the matrix material.

Abstract: Improving the quality and reliability of machines is a necessary condition for the development of mechanical engineering. Most often, the main reason for the failure of machines is the wear of working parts. The reliability of the machines is ensured primarily by achieving high-quality materials of the working parts with the required level of mechanical properties.The short service life of parts reduces the economic efficiency of many machines and industrial equipment and results in irretrievable metal losses.Under conditions of wear that are not associated with large impact loads, white wear-resistant cast irons, which wear resistance is 5-10 times greater than structural steels, have shown themselves well.Grinding and the main processes of non-ferrous and ferrous metal ore-dressing, as well as coal, mining and chemical raw materials are associated with the need to process large volumes of ore slurry (pulps). For the implementation of complex dressing technological schemes at modern factories and the removal of refuse materials, centrifugal sand and soil pumps are widely used, the service life of which is limited. Impellers, bends, and sealing elements are the first to break down, resulting in significant repair costs and reduced productivity due to forced downtime [1-3].To replace worn out parts, it is necessary to remove the pumps from the operation, or install redundant pumps for the main technological stages, which takes up to 20-25 % of the productive time. If we take into account the fact that due to the wear of these parts, the pumps have lower productivity, then the total losses on a national scale are enormous.The low durability of the cast working parts of the pumps is related to the fact that the properties of used alloys do not always correspond to the operating conditions. But even parts made of the same cast iron composition and working under the same conditions have a different service life. This is due to the fact that changes in the concentrations of alloying elements within the grade composition strongly affect their properties [4-6].

Abstract: In this work, the characteristics of the cast structure formed under various conditions of slab casting and the micro-structure of hot-rolled sheets made from them are studied by a complex of chemical and metal-graphic analysis methods. This article presents the results on cast structure's dispersion studying of continuously cast slab that depend on the casting speed as well as hot rolled steel's the microstructure and mechanical properties produced from experimental slabs. A comprehensive study shows that continuously cast slab's solidification rate determines the dispersion of the dendritic structure and the microscopic inhomogeneity degree. It is established that the dendritic structure density is the degree indicator of cast steel’s microchemical homogeneity. In all structural zones and in the whole thickness of a continuous slab with a thickness of 105 mm, the dendritic structure density and the micro-chemical homogeneity increases with increasing crystallization rate. Using the methods of quantitative metallography, it is shown that with an increase in the crystallization rate, the resulting cast structure becomes significantly dispersed. The study revealed a pattern between the initial austenitic structure of a continuously cast slab obtained at different crystallization rates and the structure of hot-rolled rolled products obtained by direct rolling, when hot slabs are placed in a heating furnace before phase transformations γ→α in the steel structure.

Abstract: Metal-polymer composites are advanced materials for the aerospace, automotive and railway industry where details and elements of construction are affected by impact, cyclic and vibration loads. In the present work layered composites based on steel, aluminum alloy and rubber as intermediate layers were obtained by cold and hot bonding using adhesives. Adhesive lap-shear bond strength of layered composites fabricated by various techniques was determined using tensile shear test. To evaluate the mechanical behavior of layered metal-rubber composites under simulated operational conditions static, dynamic and cyclic, three points bending tests were carried out. The results of mechanical tests of these composites indicated that hot bonding is the most preferred fabrication method for the formation of increased mechanical characteristics.

Abstract: The present paper is aimed to investigate the effect of modifiers, such as poly (phenylene sulfone) and poly (aril ether ketone), on physico-mechanical and thermophysical properties of heat-resistant epoxy-anhydride binder based on EHD epoxy resin. It was found that the addition of poly (phenylene sulfone) and poly (aril ether ketone) can improve mechanical and impact strength characteristics of the binder with no reduction in heat resistance and thermal stability.

Abstract: This present study has been re-established to investigate failure mode and resistance characteristics of the PC/ABS blends and their ABS constituents under impact for a range of rubber contents. This present study has still been experimentally performed under an instrumented-drop weight impact test (DWIT) at a room temperature. It has been finally revealed that with a particular size of rubber particle, content of rubber significantly influenced impact failure modes and impact resistances of the PC/ABS blends and their ABS constituents as well. The test results showed that impact strength of the blends was improved about 23.22% and 155.33% due to increase in content of rubber up to 15 wt% and 20 wt%, respectively. There was also found that an increase in impact toughness of the blends for 57.48% and 239.23% was due to increase in content of rubber up to 15 wt% and 20 wt%, respectively. Whilst, impact strength of the ABS was improved about 392.98% and 190.12% due to increase in content of rubber up to 15 wt% and 20 wt%, respectively. An increase in impact toughness of the ABS for 308.20% and 172.56% was due to increase in content of rubber up to 15 wt% and 20 wt%, respectively.

Abstract: There is an increasing amount of plastic waste generated all around the world, especially by developed countries. Polyethylene Terephthalate (PET) is one of the most widely used plastics in the world and after recycling it should be used economically and productively. The need to develop an appropriate use for recycled material is imminent. A composite is developed using recycled PET matrix reinforced with fiberglass powder, sawdust and gypsum to maximize the sustainable potential of recycled materials. Izod Impact test specimens with varying weight fraction of fiberglass powder as 12%, 15%, and 19% made as per ASTM D256 standard are tested and the results are discussed in this paper.

Abstract: Polycarbonate (PC) has the high impact strength, whereas Polymethylmethacrylate (PMMA) possesses the high tensile strength. Both of them have been widely used for optical elements in illumination. This paper aims to investigate mechanical properties including tensile and impact strengths of PMMA/PC blend with 50 percent of PC concentration by injection molding process. Tensile and impact specimens were designed following ASTM, type V and were fabricated by injection molding process. Taguchi technique was employed to figure out the optimal process conditions for maximum tensile and impact strengths. The processing conditions such as melt temperature, mold temperature, packing pressure and cooling time were applied and each factor has three levels. As a results, melt temperature has been found to be the most significant parameter for both tensile and impact strengths and cooling time is the least significant parameter for the mechanical properties.

Abstract: The results of experimental studies of the impact strength of samples of concrete and steel fiber concrete are presented. For dispersed reinforcement, three types of steel fiber were used - with bent ends, wave and flattened. Tests were conducted to determine the static and dynamic bending strength, and then - impact tests on the pendulum headstock MK-30. It was found that the impact strength increases significantly in the presence of fiber, but the type of fiber has almost no effect on it. Since specimens reinforced with a fiber content of 1.0 and 1.5% differ slightly in impact strength, 1.0% dispersed reinforcement in volume is recommended, both under static and dynamic loads.

Abstract: This study presents an experimental study on failure modes and resistances of polycarbonate (PC)/Acrylonitrile Butadiene Styrene (ABS) blends and their ABS constituents under a drop weight impact test (DWIT). Failure modes and impact resistances such as impact strength and impact toughness of such blends are generally influenced by molecular weight of the PC, rubber content and size of rubber particle in ABS system. A preliminary study on ABS materials using a DWIT showed that size of rubber particle not only determined their failure modes but also influencing their resistance characteristics. However, in a previous study performed using the similar DWIT on PC/ABS blends with a 10 wt% rubber content, it was revealed that size of rubber particle did not significantly influence their resistances. Their failure modes were even macroscopically very difficult to be distinguished. This study, hence, is aimed to further explore role of the size of rubber particle on failure mode and impact resistance characteristics of the PC/ABS blends and their ABS constituents with a higher rubber content. The impact test results have revealed that with a 20 wt% rubber content, size of rubber particle only influenced the resistances of the PC/ABS blends. It did not significantly contribute to affect failure mode of the PC/ABS blends. Whilst, it significantly influenced failure modes and resistances of the ABS. The DWIT results also re-confirmed that blending a brittle ABS into PC led to produce a tougher PC/ABS blend.