Papers by Keyword: Tensile Strength

Abstract: Modern industries are looking for a replacement of existing materials with a lightweight polymer-based reinforced material. In general, the polymer materials are reinforced with natural fiber, animal fiber, and wood fiber. This work deals with the importance of animal fiber in making a composite. The most widely used polyester resin is used as matrix materials and uniform sized (10-20mm) sheep wool fiber is used as reinforcement materials for making sheep wool reinforced composite. The random orientation of fibers was adopted for three different weight percentage (wt%) as 20%, 30%, and 40%. All the different weight fraction of composites is developed by using a compression molding technique. The compression mold ejected material is sized as per the ASTM standards for various tests. The tensile properties and hardness of the composite is determined experimentally. Scanning Electron Microscope image is taken to analysis the interfacial properties, internal structure and cracks of the fabricated composite.

Abstract: Light metal Al alloys are presently used in aerospace and industrial applications. Hence, in the present study choice of material will be LM2 aluminum alloy and processed by multi-axial forging (MAF) technique at ambient temperature for different number of passes with an equivalent strain of 0.18, 0.36 and 0.54. Microstructural analysis was carried out on unprocessed and processed samples with scanning electron microscopy (SEM). As the number of MAF pass increases the average grain size was reduced because of plastic deformation by plane strain condition. Mechanical properties like Vickers hardness (VHN), tensile and compression test were carried out. Ultimate tensile strength (UTS) was increased after each pass of MAF due to strain hardening effect. After 3 MAF passes the compression strength was reached to maximum of 495 MPa as compared to as received sample 315 MPa and hardness, increased to 81 VHN as compared to 55 VHN for the received samples. The fractography analysis was explained using SEM images. As the number of passes increases dimple size reduces as compared to as received samples and which will be revealing the ductile mode of fracture.

Abstract: Friction stir welding (FSW), a solid-state joining process is extensively using in the welding of aluminum alloy sheets. In order to save energy and reduce emission, lightweight materials like aluminum alloys were introduced into steel car body, which requires the development of effective joining processes. In the present study, welding was carried out in two different conditions, in the air (CFSW) and underwater (UWFSW) at various welding speeds to weld 5052-O aluminum alloy sheets. The effect of UWFSW on microstructural developments, mechanical properties, and formability was evaluated and compared. Grain refinement is an important opportunity to improve the mechanical properties of FS welds. Considerable grain refinement was obtained in UWFSW joints, which is smaller than that in the CFSW joints. The results indicated an increase in tensile strength, hardness, the percentage of elongation, and formability of UWFSW weld sheets. The results of the tensile test, hardness test, microstructure and fractography as in good correlation with improved properties.

Abstract: From the last few decades, biodegradable composites have become best alternatives over the petro based polymer because these degrade in the simple compound in the natural environments. Among the available biodegradable polymers, polylactic acid (PLA) is more popular due to its biocompatibility and mechanical properties, that can be used in the biomedical application, such as sutures, bone and ligament fixation screws etc. In this study, synthesis of PLA was performed by ring opening polymerization and Calcium phosphate/Polylactic acid (PLA) bio-composites were prepared by melt mixing technique. Tensile properties of these composites are investigated to assess its feasibility in biomedical and food packaging application.

Abstract: The present research includes the analysis of mechanical properties of A356/ hybrid metal matrix composite. The mechanical behaviour - hardness, ductility, tensile and yield strength were studied. Reinforcement of these composite specimens were with a weight percentage of (wt - %) 10%, 20% and 30%. The microstructure of these specimens at different wt - % of reinforcements were viewed under an optical metallurgical microscope. It was observed that at 30 wt - % of reinforcement addition, there was a finer distribution of reinforcement particles and as the wt - % decreased, much leaner distribution was observed. The hardness test was carried out using a Vickers Hardness Tester. From the experiment it was noted that with an increase in the amount wt - % of reinforcement, there is a subsequent increment in the mechanical properties except in the case of percentage elongation, which was observed to decrease with an increase in the reinforcement content.

Abstract: The consumption of natural resources like sand and stones for concrete production has resulted not only in their scarcity but also in environmental degradation associated with their extraction, and air pollution due to the generated quarry dust as result of the rock crushing. Also, with increase of mining sites in Rwanda, the amount of mine tailings has extremely increased, and their dumping is becoming a big challenge. The purpose of this study was to search for an engineering solution to the above dual problem, analyzing the performance of both mine-tailings and quarry dust as potential replacements for ordinary aggregates in concrete. The methodology consisted of evaluating the properties of the two materials, and then the analysis of strength characteristics for the new concrete manufactured using the two new aggregates. Concrete preparation was done by keeping constant the mine tailings portion as coarse aggregate, while partially replacing river sand by quarry dust at different fractions as 0%, 10%, 30% and 50%. It was established that, comparatively to normal concrete at 28 days, the compressive and tensile strengths of concrete with mine-tailings and river sand increased from 27MPA to 37.5 MPA, and from 1.9 to 3.1 MPA respectively on one hand, and on the other hand the compressive and tensile strengths decreased with partial replacement of river sand by quarry dust from 37.5 to 27.9MPA and from 3.1 to 2.3 MPA at replacements from 0% to 50% respectively. It was concluded that mine tailings and quarry dusty can be used together as concrete new aggregates in replacement of ordinary aggregates, with a due attention to concrete workability and its area of application.

Abstract: Structural retrofitting with composite materials proved to be an effective technique for rehabilitation of degraded or damaged masonry and concrete buildings. Nowadays, Fiber Reinforced Cementitious Matrix (FRCM) composites are widely used as externally bonded strengthening systems thanks to their high performance, low weight and easiness of installation. Several experimental tests and numerical studies are currently available concerning the tensile and bond behavior of FRCM systems, but a debated and still open issue concerns the methods for the mechanical characterization of the mortar used as matrix within the strengthening system. The present paper analyses and compares different test methods for determining the matrix tensile strength. Pure tensile and flexural tests have been carried out on different mortar matrix samples. In order to evaluate which is the most suitable value to be considered for a correct interpretation and modeling of the composite system, the experimental results obtained through flexural tests on standard mortar specimens have been compared with the outcomes obtained from direct tensile tests on FRCM coupons. The present study represents only a first step for the definition of the most appropriate test method for the mechanical characterization of the matrix used within FRCM strengthening systems.

Abstract: An unalloyed ductile cast iron with a multiphase structure is designed by a novel austempering process. The designed austempering treatment consists of initial rapid quenching to 180°C after austenizing at 890°C for 20min, and finally austempering at 220°C for 240min. A multiphase structure comprising lenticular/needle-like prior martensite, fine needle bainitic ferrite and film retained austenite is obtained. The excellent mechanical properties, with a tensile strength of 1530MPa and an elongation of 3.1% can be achieved by controlling the matrix microstructure of 12% prior martensite, 15% retained austenite with 1.64% carbon content, and 73% bainitic ferrite. This is mainly attributed to prior marteniste which can promote refinement of multiphase colonies.

Abstract: In this paper, the carbon fiber and ABS composites were prepared in different carbon fiber power mass percent by the twin screw extruder. The mechanical properties of the ABS/CF composites were studied in different process parameters by injection molding. The influence of mold temperature, melt temperature, packing pressure and injection pressure on the mechanical properties was analyzed in different carbon fiber composites. The results show that with the content of carbon fiber increase, the tensile stress of the composite materials also increase. The effect of different carbon fiber power content on tensile stress is greater compared with process parameters.

Abstract: Acrylonitrile-butadiene-styrene (ABS) was modified by aluminum oxide (AL₂O₃), talcum powder, kaolin and CaCO₃. ABS samples were printed by 3D printer after the ABS silk was made. Then the mechanical properties, morphology, melt flow rate were studied in this article. AL₂O₃ has the best enhancement effect on ABS than other particles, and the melt flow rate was improved when content of AL₂O₃ less than 10%.