NUST Institutions Library Catalogue Search for 'an:"119583"'

Optimization of machining parameters of Nomex honeycomb core for the development of a mesoscale numerical model to predict deformation and failure in core structures /

By Habib, Hassan . . 68cmp. ; 30cm..

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Impact analysis of the Cement Manufacturing Industry to Reduce Health & Enviromental Issues in Pakistan /

By Khan, Muhammad Ahtsham. . 68p. 30cm.

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Investigation of 3D Printed Honeycomb Cores by Varying Printing Parameters for Different Loading Conditions /

By Rashid, Muhammad Fahad . . 69p. , Light weight components having greater strength and lower manufacturing cost are the need of the hour especially for aerospace industries. For this, honeycomb sandwich structures of various materials and parameters are developed by Additive Manufacturing (AM) to meet the desired output of sufficient strength to withstand compression and flexural loading. In this paper, the honeycomb structures are fabricated using a fused filament fabrication (FDM) technique. The effect of different printing conditions on the compressive and flexural properties of the 3D-printed honeycomb structures made of PLA, ABS and PLA+ polymeric laminates are investigated experimentally and analyzed by Taguchi and ANOVA (Analysis of Variance). Three build orientations, i.e., 0, 45 and 90 degrees, with layer heights of 0.1, 0.2 and 0.3 mm are considered for the 3D printing. Moreover, Multi-objective optimization is performed to optimize the strength and printing time (cost) of L27 array samples. Results show that 90ᵒ and 0ᵒ build orientations with 0.3 mm layer height being PLA and PLA+ the best materials are the optimum conditions for compressive and flexural mode of testing, respectively. The results deduced that compressive and flexural samples could withstand maximum load of 69,000N and 120 N with minimum printing time. Thus. it would be fruitful in harnessing energy for the development of sustainable printing of durable components. 30cm.

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Experimental Investigation of Flexural Properties of Fibre Glass Reinforced Polymer /

By Abbas, Asad . . 48p. , Additive manufacturing is an advanced manufacturing technology in which computer aided design is converted into STL file and then fed to 3D printer after slicing the design with the help of slicer software. Masked Stereo-lithographic apparatus (MSLA) is a type of liquid based 3d printer in which an array of LED is used to cure the photosensitive polymer resin with the help of ultra violet radiations. These radiations solidify the resin on platform of printer when fall on exposed area. The platform rises for next layer and this process continues until all the layers are cured and part is manufactured. The time to manufacture the part depends on layer thickness, height of part and the orientation of the part on platform. These parameters are set during the slicing process. We can find many applications of SLA printers in fields like engineering, medical, dentistry, jewelry and many others. These printers now a day are used to manufacture the final parts apart from the prototypes but there is limitation in the availability of resin of required mechanical strength. So to overcome this problem researches are carried out to manufacture polymer composites in different ways. This research focuses on using short glass fibres of different strand lengths as reinforcing material to matrix photosensitive polymer. The glass fibres of 5, 10, 15, 20, 25, 30, 35 and 40 mm lengths are used as reinforcing materials and nine specimens including neat one are manufactured in MSLA printer. The flexural properties of these specimens are obtained by performing 3-point bend test on universal testing machine as per ISO 14125 standard. The graphs of the force vs deflection are obtained and flexural strengths and flexural modulus is calculated and compared for all the specimens. It was observed that the flexural strength as well as flexural modulus of these specimens was increased initially for 5 and 10mm strands lengths and then started decreasing as the strands length increases. The maximum value of flexural strength and flexural modulus was obtained for 10mm glass fibre length and minimum for 40mm. 30cm.

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Ultrasonic Assisted Micro Milling of Inconel 718 /

By Mirza, Asim Ali . . 56p. , A super alloy with high temperature resistance, high corrosion resistance, and high strength is iconel-718, which is based on nickel. In the biomedical, aerospace, marine, and automotive industries, nickel-based super alloys are frequently used. The super alloy inconel-718 is difficult to machine and to cut. For greater surface roughness, little tool wear, and minimal burr formation, which produces better results than conventional micro milling, a methodology using ultrasonic assisted micro milling is developed to address this problem. This experimental investigation uses 0.5mm diameter cutting tools with various coatings, such as TiAlN, TiSiN, and nACo, to evaluate the effects of various machining parameters on surface roughness, tool wear, and burr development. With four levels and five parameters—cutting speed, feed rate, depth of cut, coating, and amplitude of tool vibration—Taguchi L16 array is used to create experiments. The analysis of variance is performed using Minitab software. It provides the percentage influence of each element, and we can identify the best and worst set of parameters to achieve the desired results using main effect plots. For multi-objective optimization, Grey Relational Analysis (GRA) is used to determine the best and worst parameter levels for each of the three answers. Confirmatory experiments revealed that ultrasonic aided micro milling produces better results than traditional micro milling with an amplitude of vibration of 9 m. 30cm.

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Optimization of FDM Printing Parameters to Enhance Mechanical Properties in Z-Direction /

By Haris Ali Nasir, Muhammad . . 88p. , Fused deposition modeling (FDM) is a commonly used additive manufacturing process that offers new opportunities for creating complex geometries that are difficult to produce using traditional production methods. However, the use of FDM technology in practical goods is limited due to anisotropic strength concerns. This means that the strength of parts created using FDM in the build direction (Z direction) can be much lower than in the X-Y directions. The objective of this study is to specifically examine a polymer called Polycarbonate (PC). The effects of layer height, printing temperature, and printing speed on the Z-direction tensile characteristics of 3D-printed PC samples were systematically explored using Taguchi design and response surface methodology (RSM). The RSM results indicate that the thickness of the layers has the greatest impact on the bonding between interlayers during printing. The optimal tensile characteristics for 3D-printed polycarbonate (PC) parts were obtained using parts generated with a layer thickness of A = 0.1288 mm, a printing angle of B = 270 °C, and a printing speed of C = 40 mm/s. The results confirm that printing PC material with the optimal conditions significantly enhances the bonding between interlayers in the build direction. An increase of 39.23% in the tensile strength of 3D printed parts was achieved 30cm..

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Investigating the effect of various cellular configurations and geometrical parameters on the strength-to-weight ratio of honeycomb cores designed for Additive Manufacturing /

By Khizar ,Umair . . 83p. ; 30cm..

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