Manufacturing Engineering

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    Development and Analysis of Composite Material using Honey comb Orientation of Bamboo Fiber and Epoxy Composite for Prosthetic Socket Application
    (Addis Ababa University, 2023-06) Yelshaday Regasa; Henok Zewdu (Mr.)
    This thesis focuses on utilizing honeycomb fiber orientation techniques to develop a prosthetic socket with enhanced mechanical properties at a lower cost. The current challenges in prosthesis production include the high cost of fibers and the inadequate strength of the composite fiber. To address these issues, this research explores the tensile characteristics, water absorption and impact strength of bamboo fiber reinforced epoxy composites with an optimized material mix ratio design. The Finite Element Method for Numerical Analysis is employed to predict the desired properties of the composite material. Using numerical analysis software solutions, the stacking sequence is determined based on established standards. The newly designed prosthetic socket is evaluated for improved qualities, such as stance stability, speed control, multiple speed adoption, shock absorption, and reduced weight throughout the entire cycle. By closely emulating nature, the study investigated the relationship between woven fiber orientations and honeycomb pattern fiber orientations. It examines the optimal material mix ratio design, as well as the best fiber orientation pattern and angle of fiber orientations. The obtained results include a tensile strength of 53.4 MPa, compressive strength of 57.6 MPa, flexural strength of 64.55 MPa, impact strength of 13.02 J/cm2, and water absorption rate of 2.31%. The findings of this research aim to contribute to the development of low-cost, high-strength composite materials for prosthetic sockets. Prosthetic socket designers can utilize these recommendations to improve the overall performance and durability of prostheses.
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    Integration of Rice-Husk Filler on Physico-Mechanical Characteristics of Hybrid Sisal and Glass Fiber Reinforced Epoxy Composites for Neck Brace.
    (Addis Ababa University, 2023-10) Kiros Gebreegziabher; Kiros Gebreegziabher (PhD)
    Despite the fact that composites have better corrosion resistance, light weight, good consolidation, and are available in large sheet sizes and wide range of thicknesses, physical and mechanical properties still need to be examined and improved to meet the needs of a wide range of applications. At the time of operation of composites some mechanical properties are significantly influenced by the presence of voids. The voids are the locations where stress is concentrated which accelerates the failure process leading to early and catastrophic failure of the composite. Different investigation also described important properties, including water resistance, weathering, surface smoothness, stiffness, dimensional stability, machinability, shrinkage, voids and temperature resistance, can all be improved through the proper use of fillers. The objective of this research work is to develop and characterize the physico- mechanical properties of hybrid sisal and glass fiber with rice husk filler epoxy composite. Hand lay-up fabrication technique will be used to prepare the specimen with 20% fiber and 0%, 2%, 4%, 6% and 8% rice husk filler which are then compressed using a compression molding machine. compressive strength (ASTM D3039), flexural strength (ASTM D790), impact energy tests (ASTM D256) and physical properties such as density (ASTM D792) and water absorption (ASTM D570) was conducted using ASTM standard. From the experiment executed, it is observed the flexural strength, water absorption and void content improved with addition of filler. However, compression and impact strengths slightly reduced. The design of composite structures was then evaluated using Ansys ACP analysis in order to utilize it for the required application. In compared to the others, the hybrid sisal and glass fiber reinforced epoxy composites with 2% and 4% rice husk filler exhibit outstanding performance.
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    Fabrication, Characterization and Simulation of Flax-Sisal Fiber Reinforced Epoxy Hybrid Composite for Prosthetic Socket
    (Addis Ababa University, 2021-07) Luna Geo; Desalegn Wogaso (PhD)
    Prosthetic limb socket is the major part of a prosthetic leg and arm. It provides comfortable connection, transfers the load, ensures stability between the residual limb and the device. This study aims to investigate tensile, flexural, compression, impact and water absorption properties of Flax-Sisal Fiber Reinforced Epoxy Hybrid Composite. The research also targets to explore its application for prosthetic socket. Hand-layup method was utilized to fabricate thirteen composite specimens having 30mm fiber length and fiber-matrix volume percentages of 40-60, 30-70, and 35-65 according to ASTM standards. Eight composite specimens were treated with 5% NaOH. Comparing the thirteen composites, the result showed the treated composite with F25%-S15%-E60% had superior mechanical and physical properties with tensile strength of 68.40MPa, flexural strength of 145.7MPa, compression strength of 45.64MPa, impact energy of 10.83J and water absorption percentage of 3.66%. In addition, using ANSYS 2020, Prosthetic socket was modeled and loading conditions were applied on composition F25%-S15%-E60% from this, maximum von missed stress of 2.214MPa and deformation of 0.0064mm was obtained. Based on the results and analysis, the selected Flax-Sisal-Epoxy hybrid composite has the potential to be further developed as an alternative material of prosthetic socket.
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    Optimization of Machining Parameters in Drilling Hybrid Sisal – Cotton Fiber Reinforced Polyester Composite
    (Addis Ababa University, 2021-07) Nurhusien Hassen; Desalegn Wogaso (PhD)
    As compared to metals, composite materials machining is a challenge because the cutting tool needs to move through the matrix and fiber alternately, which have various properties. The objective of this work is to optimize the machining parameters in drilling hybrid sisal-cotton fiber reinforced polyester composite (HSCFRPC) to reduce the hole roundness error and surface roughness using Taguchi's method. The influence of machining parameters such as spindle speed, drill diameter, and feed rate on the surface roughness and roundness error of HSCFRPC during the drilling process on the vertical CNC milling machine have been analyzed using the methods of Taguchi’s design of experiment. A series of experiments based on 𝐿16 orthogonal arrays were established with different feed rates (10, 15, 20, 25 mm/min), spindle speeds (600, 900, 1200, 1600rpm), and drill diameter (6, 7, 8, 10mm). The measurement of roundness error and surface roughness have been carried out using ABC digital caliper and Zeta 20 profilometer respectively. The experimental values are gathered and analyzed using the MINITAB 19 commercial software program. To create a connection between the chosen drilling parameters and the quality attributes of the drilled holes, linear regression equations have been established. Signal to noise (S/N) ratio analysis and analysis of variance (ANOVA) were performed to identify the rank, percentage contribution and optimum values of these machining parameters such as spindle speed, drill diameter, and feed rate to reduce the roundness error and surface roughness. Based on the analysis the best combination of the optimum machining parameter values (1600rpm, 25 mm/min, and 6mm) are selected to reduce both roundness error and surface roughness of the composite. Finally, verification of the recommended machining parameters have been achieved and the values of roundness error and surface roughness obtained are 0.1mm and 64.8μm Ra respectively, which satisfies the objective of lowest roundness error and surface roughness. The verification result shows that the recommended machining parameter values to reduce roundness error and surface roughness based on Taguchi’s analysis were precise and fitted to the optimum values.
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    Design, Analysis, and Performance evaluation of Cellular Manufacturing System for Conventional Manufacturing Factory : A case of Addis Machine Spare Parts Manufacturing Industry
    (Addis Ababa University, 2023-10) Paulos Girma; Desalegn Wogaso (PhD)
    This thesis assessed the performance problems at the Addis Machine Spare Part Conventional Manufacturing Factory (ASPCMF) under the Ethio Engineering Group (EEG). The case factory has been faced a number of manufacturing system challneges according to the data collected from the operations department of the factory. After the analysis performed based on the existing layout evaluation, problems identified were higher idle time of machines and longer travel distances of parts that lead to lower performance. From the study of the previous performance survey done in 2021, the overall performance recorded was 38.03%. After analyzed the existing layout performance using FlexSim software 31.8% performance recorded. This lower performance identified necessitates the requirement to design a new layout and analyzed the performance based on machine utilization and travel distance of parts. Therefore, the purpose to assess the existing manufacturing system based on machine utilization and travel distance of parts led to design, analysis, and evaluate the performance by proposing a cellular manufacturing system. In the design work a 22 part family was created using the Optiz coding system, which was based on hybrid coding system. A method of machine grouping in an incident matrix was developed to form 20 cells. The rank Order clustering algorithm was used to cluster parts and machines within the cell. This minimized 45 duplicated machines in bottlenecks, while increasing the machine utilization of 43 machines in the cluster formed. The designed cell in the cluster was evaluated through grouping efficacy (GE) of parts allotted in cells to achieve optimal effectiveness in cell utilization which was 91% cell efficiency. The CRAFT algorithm used to identify the part flow within the department and the effectiveness of machine arrangement analyzed based on part travel distance that was reduced into 1,425 m from the existing layout 2,236.10 m which increased floor space available so that, an improved layout was proposed. The analysis was performed to evaluate the designed cell, the performance simulation shows that 88.37% of the proposed cellular layout demonstrates significant enhancemenent compared to the existing layout, which was only 31.8 %. The performance simulation was conducted using FlexSim software. Finally,the individual machine utilization percentage was determined and compared between the proposed layout and the existing layout.
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    Development and Characterization of the Mechanical Properties of Al2024 alloy Reinforced with SiO2 and Bagasse Ash Composite
    (Addis Ababa University, 2021-07) Senait Menbere; Shantha Kumar (Assoc. Prof.); Henok Zewdu (Mr.) Co-Advisor
    Silica sand and sugarcane bagasse-ash (BA) are used as reinforcement for Aluminum alloy (Al2024) based hybrid composites. The Aluminum matrix hybrid composites were fabricated by stir cast at 750°C. The reinforcement weighted by volume fraction ratio 5%, 10% & 15% of matrix and reinforcements, <63μm particle size, stirring the slurry at 650rpm for 10 minutes were the parameters used for the fabrications of aluminum matrix hybrid composites. The development and experimental findings of aluminum matrix hybrid composite mechanical properties were performed by adding silica sand and bagasse ash as reinforcement with different composition proportions. The addition of this reinforcement with nine compositions proportion, in range of 5-15% with 5% interval. For a maximum improvement of the material properties, solution heat-treatment (T3-temper) was performed. The effects of the reinforcements have been examined through different mechanical tests. These tests were implemented using Rockwell hardness indenter, bending, and tensile strength by universal testing machines, and optical microscopy was used to characterize the microstructure of composite specimens. Specimens were prepared as per the ASTM E18-15 for Rockwell hardness and E8M/16a for tensile, E290 for bending test specimen standards. The samples are modeled using Solid works 2017, and its analysis was performed by ANSYS 19.2. The analysis result showed a higher effect of the reinforcing bagasse-ash with different compositions in aluminum matrix reinforced composites. Enhanced mechanical properties have been achieved in the 3rd case compared to the 1st and the 2nd BA & SiO2 combination. It shows that the selection of BA & SiO2 as reinforcement has one of the essential criteria for fabricating aluminum matrix reinforced composites. The result showed that the hardness of the composites increased slightly with an increase in bagasse ash content with a maximum increment of 15%. The maximum mechanical properties were observed for the Al2024 reinforced composite at 5% bagasse ash and10% silicon dioxide compositions. Tensile strength increased to a maximum value of 560MPa, and also flexural strength increased to a maximum value of 482MPa at 10% SiO2 and 5% bagasse ash compositions. Hybrid composite superior properties are observed in tensile strength, flexural strength, and hardness than single reinforced Al2024/ SiO2 metal matrix composites. Also, for the application of fuselage-skin panels, the reinforced and heat-treated Al2024/SiO2/BA-T3 improved a better stress resistance performance than the unreinforced Al2024- T3/T351 through FEA.
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    Fabrication And Evaluation of Mechanical Properties of The Hybrid Coffee Husk and Enset Fiber-Epoxy Reinforced Composites
    (Addis Ababa University, 2023-06) Shambel Dibaba; Desalegn Wogaso (PhD)
    in modern times there is a growing concern about replacing polluting and not recyclable synthetic fibers, as well as rare wooden fibers, with sustainable lignocellulose fibers derived from agricultural leftovers for reinforcement bio-composites. Currently in Ethiopia, the accident rate of vehicles on the road is increasing. Along with that, Vehicle security is a significant topic of study to safeguard. not only structures but also occupants in the event of a crash. In the other side the fast increase of population and development of cities required demand for transport, hence to full fill the demand recently the vehicles are imported in large amounts at the same time which requires accessory’s for replacement of their parts, so the front bumper of those vehicle is the most parts demanded due to it is the most exposed part during crash. The Enset fiber and coffee husk were collected from Ethiopia's Southern Nations, Nationalities, and People's Region (SNNPR) Gedeo zone, Yirgachefe district. Sun-dried Eset and coffee husk were treated with a 5% sodium hydroxide mixture to remove more cellulose, hemicellulose, lignin, and additional fiber chunks to increase binding and facial shear strength. Following that, Enset-coffee husk fibers reinforced hybrid composite was created utilizing a hand layup method on the 40-60%, 30-70%, and 20-80% fiber weight percentages of matrix weight to total fiber volume. Tensile, compressive, its impact, flexural, and absorbance of water tests were then performed to determine which constituent of the composite had higher strength under load. While the mechanical and physical properties of the composites were assessed, the composite C5 with E20%-CH10%-E70% possessed the best mechanical and physical properties, with a tensile strength of 43.30MPa, flexural strength of 93.38 MPa, compression strength of 21.23MPa, impact energy of 3.5J, and water absorption percentage of 3.55%. In addition, the front bumpers was modeled in ANSYS 19.2 and composite C5, yielding an optimal von missed stress of 39.119MPa and distortion of 15.09mm. According to the findings and analyses, the chosen Enset-Coffee husk-Epoxy hybrid composite might be explored subsequently as a low-speed crash replacement material for the front bumper.
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    Effect Of Fiber Orientation & Volume Fraction On The Mechanical and Thermal Properties Of Bamboo Fiber Reinforced Epoxy Composite For Laptop Case Application
    (Addis Ababa University, 2023-03) Tigist Mesfin; Dessalegn Wogaso (PhD)
    Protecting one‟s laptop is an undeniable thing because of its massive personal data stocking, it being one‟s working media (tool) and its expensiveness to replace it if it got physically damaged by any means. This work aims to investigate the effect of fiber volume fraction and orientation on mechanical (tensile, flexural, and impact) strength, thermal resistance and water absorption properties of bamboo fiber reinforced epoxy composites experimentally. It aims to explore its applicability as a protective casing for personal computers. Bamboo fibers were treated with 6% NaOH for 2 hours and 1600c temperature for 3 hours. Laminates were fabricated by hand lay-up technique in a mold and cured under light pressure at room temperature followed by curing for two days. Bamboo laminates were prepared by varying three orientations (0/450, 0/300 & 0/900) of fiber and four fiber volume fractions from 20%, 30%, 40%, and 50%. Specimen preparation and testing were carried out as per ASTM standards. The highest tensile, flexural and impact strength were obtained from composite with 30% fiber 70% epoxy matrix composition at 00/900 orientation having 48.85MPa, 38.17MPa and 170.57 J/m2 respectively. The lowest water absorption percentage was obtained from treated composite with 20% fiber 80% epoxy matrix composition at 00/900 orientation having 1.71% of absorption. Evidently 30% bamboo fiber reinforced epoxy composite has very high thermal resistivity almost equal with wood, which makes it non-conductive material. Based on the results and analysis, the selected bamboo fiber -epoxy composite has the potential to be further developed as protective case for laptops.
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    Optimization of process parameters in Friction Stir Welding of dissimilar aluminum alloys (AA6061–T6 and AA5052–H32)
    (Addis Ababa University, 2023-03) Wondu Tesfaye; Henok Zewdu (Mr.)
    Friction stir welding (FSW) is a solid-state welding method mostly used to join aluminum and aluminum alloys that has been used in aerospace, railway, automotive, and marine applications. This process is used for welding dissimilar aluminum alloys. Solid-state welding processes solve several problems that occur during fusion welding of Al-alloys like heat affected zone liquation cracking, porosity, and segregation. Aluminum Alloys of two different series AA5052 and AA6061 thickness of 6mm are Friction Stir welded using process parameters like tool rotational speed (900,1100,1400) rpm, transverse speed (40,50,60) mm/min, and pin profiles (cylindrical, conical, and square). This thesis aims to optimize the mechanical and metallurgical properties of the above dissimilar combination to evaluate the performance and characteristics of the welded joints. The combined Taguchi and Grey relation analysis experimental method was chosen to construct the number of welding experiments. Analysis of variance was performed to obtain the effect of the parameters on the Friction Stir welded joints strength. The plates are successfully welded, and the welded plates are tested at room temperature to examine their tensile strength and hardness. The findings indicate that the square pin profile, the rotational speed of 1400 rpm, and the transverse speed of 40 mm/min are the optimum parameters for joining these dissimilar joints. A fine and uniform distribution of strengthening precipitates was found in the stir zone.
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    Process Evaluation and Performance Enhancement of Corrugated Board Fabrication. (A case of Burayu Packaging and Printing Industry)
    (Addis Ababa University, 2023-07) Yohannes Eshete; Getasew Ashagrie (PhD)
    The materials utilized, the conversion process, and other factors could all have an impact on the corrugated board performance. The objective of the thesis to quantify the mechanical strength of the corrugated board, the adhesive strength, the paper compression strength at fabrication process of investigated the pin adhesive, edge crush, box compression strength and material properties test at standardize methods. Based on the experimental result the reel size of 165,185,205,220 cm at fabrication speed on 50,65,80,95 m/min which can be used to determine varies result of compression strength exhibited at 50 m/min, and the fabricated board was the maximum, pin adhesive 356,352,351,349 Newton, edge crush 4.5,4.3,4.2,4.4 KN/m, pure box compression 112- 114 kg strength were shown. Reel size 220 cm fabricated at 80 m/min refers to the laboratory results minimum strength were performed. The Maltenfort model by correlating the measured ring crush test with the theoretical edge compression test enable to know the board strength of how much the variables degraded the strength of the combined board as of reel size 185,205,220 cm at 80 and 95 m/min during the process. The regression equation which can be used to evaluate the linear effect of the process and can be used to predict the performance of the box and enable it to enter into optimum fabricating process as well as strength improvement decisions. Boards will have better strength if they follow optimum process can be achieved by balancing and selecting the variables of fabricating speed, reel size, and material properties which helps to identify the strength of the board and evaluate the fabrication process. Overall, this study provided experimental and McKee box prediction are done for the evidence of structural performance and delamination strength of the corrugated fiber board by aligning a process through runnability.
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    Development and Characterization of Hybrid Flax -Banana Fiber Reinforced Epoxy Composite for Ceiling Fan Blade Application
    (Addis Ababa University, 2023) Zodiac Simeneh; Desalegn Wogaso (PhD)
    A fan blade is the major component of fans, it used for ventilation systems, cooling systems, refrigeration, boilers, and dust collection purposes. The materials used to fabricate ceiling fan blades are fabricated steel, cast or forged aluminum, plastic, fiberglass, or other exotic materials. The present work aims to develop and characterize the mechanical and water absorption properties of hybrid flax-banana fiber reinforced epoxy composite. In addition it examined the suitability of the composite material for ceiling fan blade application. The composite manufacturing process includes fibers extraction, fibers surface treatment, fibers property test, composite plate’s fabrication, composite specimen's mechanical and water absorption tests. Based on the experimental test result, the static structural analysis is performed to analyze the induced stress and deformation on the ceiling fan propellers. The fibers are extracted through water retting and manual extraction methods. The flax and banana fibers are treated with 5% and 3% of NaOH solution to increase the interfacial bonding between the fiber and matrix materials. The fibers are hybridized manually with 1:1, 3:1, and 1:3 fibers ratio. The composite plates are fabricated with eleven sub- composition of 60/40%, 70/30%, and 80/20% resin to fiber volume fraction. The tensile, flexural, impact, and water absorption property tests are conducted using ASTM D3039, ASTM D790, ASTM D6110, and ASTM D570-99 standards. The ceiling fan blade geometry and static structural analysis performed using Catia.V5 and Ansy’s 19.2 software. Overall, the experimental test results shows that 70/15/15% volume fraction exhibits the highest tensile strength of 68.9MPa and flexural strength of 169.14 MPa respectively. The highest impact strength result was observed on 60/20/20%volume fraction. The highest water penetration resistance was observed on 80/15/5%. Overall, the experimental test results shows 70/15/15% volume fraction has the highest tensile strength of 68.9MPa and flexural strength of 169.14 MPa. On the other hand, the highest impact strength result 10.83J is observed on 60/20/20%. In a water absorption test result, the least water absorption property is obtained on 80/15/5%. In addition, 70/15/15% has presented the second lowest water absorption property. Based on the structural analysis, HFBFREC exhibited the lower Von-misses stress of 2.4MPa and 0.9mm deformation.
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    Development And Characterization of Mechanical Properties of Al6063 Alloy Reinforced Fly Ash And E-Glass Fiber Composite
    (Addis Ababa University, 2021-07) Abebayehu Mulugeta; Mesfin Gizaw (PhD); Gezae Abera (Mr.) Co-Advisor
    Currently, one of the key concerns in automotive engineering is the weight minimization of a part without any reduction in load carrying capacity and stiffness. The present investigation deals with investigating the hardness, compression, and flexural properties of Al6063/ E-glass fiber/ Fly ash Composite as a possible replacement to the existing steel outer door panel of the Toyota Hiace four-wheel vehicle. In this study ten composite specimens were prepared as per ASTM standards size by machining operations to conduct flexural, hardness, and compression tests. Comparing the ten composites the result showed the composite with 7% of E-Glass fiber/ 6% fly ash had the maximum mechanical property of hardness and compression strength with the value of 116.73HRB and 850.31MPa respectively. And maximum flexural strength was found with composite 5% of E-Glass fiber/ 9% fly ash with the value of 340.1MPa. In this study, a volume fraction of 5% E-Glass fiber with 9% Fly ash was selected as a composite for the outer door panel because for all mechanical properties listed above it shows a better result. Then this paper effort to attain, designing less deformed and stressed than that of the existing Toyota Hiace vehicle steel outer door panel. The solid modeling of the outer door panel was done on SOLIDWORK 2017 and analyzed using ANSYSR18.1 workbench software. From transient structural analysis, it is seen that weight reduction of the outer door panel is obtained up 66.24% in the case of the composite than structural steel, and the equivalent stress-induced and deformation in the Al6063/E-Glass fiber/ fly ash composite outer door panel is 66.24 % and 26.3 % respectively less than the current steel outer door panel. Lastly, based on this result, the study concludes that the recently designed Al6063/E-Glass Fiber/ Fly ash composite outer door panel has a better presentation than that of the conventional steel outer door panel of the Toyota Hiace Van vehicle.
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    Optimization of Cutting Parameters for Milling Enset Fiber Reinforced Epoxy Composite
    (Addis Ababa University, 2022-04) Abebe Muluye; Mesfin Gizaw (PhD)
    Machining of composite materials is accompanied by fiber pullouts, fiber breakages, delamination of laminates, matrix burnings, which degrades quality and performance of the product. These challenges able to be reduced with controlled or optimized machining parameters. This study investigates the optimization of cutting parameters for end milling of enset fiber reinforced epoxy composite materials. Spindle speed, feed rate and depth of cuts were considered as an input parameter, and surface roughness and material removal were considered as quality responses. Specimens were fabricated from 30% weight fraction of enset fiber and epoxy resins with 1.5% of MEKP hardeners by using hand layup processing techniques. The fibers were extracted from Endiber Woreda, Gurage Zone, South Region, Ethiopia. The compressive, flexural and impact strength tests were performed based on ASTM standards. The test results demonstrate that, enset fiber reinforced epoxy composites have the average compressive, flexural and impact strengths of 23.2 MPa, 89.36 MPa and 114.59 KJ/m2 respectively. The milling operations have been performed on CNC milling machines at different cutting parameter levels by using 10 mm diameter HSS end mill cutters. The experimental runs were designed based on Taguchi L9 (33) orthogonal arrays. The influence of cutting parameters is determined by the analysis of variance (ANOVA) and optimization is performed by coupling grey relational analysis with principal component analysis. The results of ANOVA revealed that depth of cut has greater contributions (49.47%) followed by spindle speed (43.50 %) and feed rate (4.39 %) respectively on the gray relational grades (GRG). The optimum values of surface roughness and material removal rate simultaneously were obtained at lower spindle speed (1000) rpm, higher feed rate (300) mm/min and medium depth of cut (1.5) mm.
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    Development And Characterization of Al6061/Sic/Bagasse Fly Ash/Aloe Vera Ash Hybrid Composite as An Alternative Material for Drum Break Application
    (Addis Ababa University, 2023-07) Endashaw Getnet; Getasew Ashagire (PhD)
    Composite materials, which have low densities, are used for automotive body parts and structural functions, leading to high strength-to-weight ratios and high stiffness-to-weight ratios compared to other conventional materials. Most engineering applications nowadays in industry, such as, aerospace, automotive body parts, propellers, and manufacturing turbine blades, require better mechanical properties of material. To meet these requirements, metal matrix composite offers certain top mechanical properties such as higher transverse strength and stiffness, superior shear strength, wear resistance and compressive strength, and superior high temperature performance than other polymer and ceramic composites characteristics. This work aims to develop and evaluate Al matrix composites with better performance using low-cost reinforcements from industrial wastes and agricultural products. Fabrication and experimental study of mechanical properties of aluminum matrix (Al6061/SiC) composites the weight % of reinforcement was evaluated and compared. Al6061 matrix hybrid composites were prepared by stir casting at 700 °C and at 600 rpm of stir rotation. The parameters were used to develop the Al6061/SiC bagasse fly-ash and aloe-vera ash hybrid composite are chemical composition of reinforcements, weighted requirements for matrix and reinforcements, powder mixing, and stirring the slurry at 600 rpm for 10 minutes. Compression strength testing (ASTM Standard E9), wear resistance of samples using (ASTM G99 standards, and impact strength testing (ASTM E-23) had been conducted to characterize the developed composite. The results showed that the compression strength slightly increased with bagasse ash and aloe vera ash content. The maximum compression strength achieved in sample 6 (Al6061-10% SiC, 9% bagasse ash, and 11% Aloe vera ash) is 376.3 MP, and the average value is 376.3 MP. A low average value of wear (in microns) has been found in sample 6 (Al6061-10 %SiC-9% bagasse ash - 11 % Aloe vera ash), and the value is gained at 64.8 microns, this shows more wear resistance in the composite sample as compared to other samples. The impact test result shows that samples gives better energy absorbed which is 4.79J. Therefore, industrial waste, bagasse ash and agricultural product like alovera can enhance mechanical properties which mean hybrid composites had better properties than single-reinforced composites. Therefore, Al 6061/SiC with bagasse and alovera ash composite is suitable for applications where less density with high yield strength and hardness are predominantly required for drum brake application.
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    Analytical and Numerical Modelling of Failure in Aluminum Matrix Composite for Connecting Rod Application
    (Addis Ababa University, 2022-06) Ephrem Yemane; Desalegn Wogaso (PhD)
    The failures in composites are due to failure in their matrix, re-enforcement parts, or both. Failure in the composite structure could cause pin failure, stress failure, fatigue failure, hydro lock as well as overheating of the connecting rod. Thus, the implementation of analysis and predicting tools is preferred to prevent failures. The objective of this thesis work is to predict and analyze the failure possibilities in automobile connecting rods. The connecting rods are made of an aluminum matrix with silicon carbide reinforcements which were modeled by varying the volume fraction of re-enforcements in the form of laminates and particulates. The laminate reinforced aluminum matrix composites were modeled by varying laminate orientation while the particulate reinforced ones were modeled by varying the composite aspect ratio. The connecting rod models passed through available failure criteria like Tsai-Hill or Tsai-Wu and Von-Mises stress values. Both models were analyzed using ABAQUS software. Additionally, the particulate reinforced composites were analyzed using representative volume element /RVE/ on DIGIMAT software. The results showed that the material properties of AA6061-SiC composites increased with an increasing reinforcement volume fraction by the reduction in thickness of the bulky connecting rod. Failure in the connecting rod was predicted to occur in stress-concentrated areas located at corners where the SiC reinforcements are found, as well as, areas of load application and the middle cross-section of the connecting rod. The particulate reinforced models were preferred than the laminate reinforced ones because they sustained higher load gradients prone to less failure. The aluminum MMC’S with a five percent SiC reinforcement volume fraction in particulate form, as well as, twenty percent volume fraction SiC in laminate form with 0o or 90o orientation were found suitable for automobile connecting rod application based on the parameters provided by the author.
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    Fabrication and Investigation of the effect of Machining Parameters on the Performance of Machining Al-TiB2 Composites
    (Addis Ababa University, 2023-01) Nobel Kassahun; Henok Zewdu (Mr.)
    Aluminum-based metal matrix composite materials are mostly used to design automobile parts and aircraft structures due to their lightweight and high strength. In this study, the stir casting method was used for the fabrication because it is the most effective method for manufacturing metal matrix composites due to its more effective and fairly uniform distribution. Machining of metal matrix composites was difficult in the turning process. This study investigates optimum cutting parameters for turning Al 6061- 10% TiB2 composite materials. The mechanical properties of Al-10% TiB2 composite were analyzed using the following tests: tensile test, hardness, and impact test. Al 6061- 10% TiB2 has a mechanical property i.e. tensile test the maximum result from the specimens was 242MPa but the average was (208MPa), hardness test by Rockwell hardness test the average result was (74.9HRH), and finally the Impact result was (311.67KJ/m2). The study considered the cutting parameters which are the cutting speed, depth of cut, and feed rate as input, surface roughness and material removal rate are the responses by using coated carbide tool on a CNC lathe machine. The effect of cutting parameters on Surface roughness and material removal rate were studied and analyzed. Experiments were conducted based on the Taguchi design of Experiments with orthogonal array L9, and the optimization of the results works with Analysis of Variance (ANOVA). The optimum responses of MRR and surface roughness were obtained at high cutting speed 1500rpm, high depth of cut 1.5mm, and medium feed rate 100mm/min.