Saudi Cultural Missions Theses & Dissertations
Permanent URI for this communityhttps://drepo.sdl.edu.sa/handle/20.500.14154/10
Browse
7 results
Search Results
Item Restricted 3D reconstruction of human organs (non-biology nature) using CAD software and 3D printers(University of Dundee, 2024-08) Almohammadi, Anas; Wei, ChengThree-Dimensional (3D) printing is an evolving field, it can be used in various fields including healthcare field, which can be used for different purposes such as in pre-planning operations to help doctors plan the complex surgeries and see the entire area of interest, or it can be used to support the doctors when explaining to their patients the problem they are having, also it can be used in teaching anatomy classes, and other purposes. The 3D printing or also called (Additive Manufacturing) is a technique which produces a physical three-dimensional model by printing two-dimensional images of the required model one layer at a time and put on top of each other. It is used in medicine field by putting layers of medical images of the interior organs of the body acquired using medical imaging modalities such as computed tomography (CT) or magnetic resonance imaging (MRI). Then, the acquired images are segmented either manually or automatically to form a final virtual 3D model. Afterwards, the virtual 3D model is printed using specific materials which depend on the organ desired to be printed. This project will talk about the different types of medical images and which type is more suitable in printing. In addition, it will cover the common methods of segmentations and how to choose the appropriate materials. With the printers available in the university this project will cover the whole cycle from the scanning images to the physical 3D model. The aim of this project is printing a 3D model of the heart by using CT images of an anonymous patient from Ninewells hospital which can be used for the education purposes. The CT scans have been used in a segmentation software "InVesalius" which is an open-source software. "Meshmixer" is then used to smooth the model and get rid of irregularities and sharp edges. Finally, the model is printed in a 3D printer for educational purposes.8 0Item Restricted Environmental Life Cycle Assessment (LCA) of Centralised vs Distributed Aerospace Manufacturing(Cranfield University, 2024-09) Almegbel, Abdulaziz; Haddad, YousefThis thesis investigates the environmental impacts of manufacturing aeronautical turbine blades using two different techniques: traditional Investment Casting (IC) and Electron Beam Melting (EBM) in both centralized (CM-EBM) and distributed (DM-EBM) settings. Through a comprehensive Life Cycle Assessment (LCA), the study examines each phase of the blade's life cycle, from material extraction and processing to end-of-life recycling, offering insights into Global Warming Potential (GWP) and material efficiency. Findings reveal that although EBM scenarios have higher energy consumption and GWP during production, their lower buy-to-fly ratio indicates better material efficiency compared to IC. Furthermore, when the use phase is included, EBM scenarios demonstrate up to 85% lower total GWP than IC, due to the lower density of titanium alloy blades, which reduces aircraft weight and fuel consumption over their lifespan. The research highlights the importance of evaluating the entire product life cycle for sustainable aerospace manufacturing and suggests further exploration into optimizing EBM processes and hybrid manufacturing models to balance energy costs with long-term environmental benefits.13 0Item Restricted A Decision Framework to Select Manufacturing Method Based on Part Complexity (Additive or Subtractive)(Western Michigan University, 2024-08) Alblawi, Trad Mutair; Burns, JamesAt the end of the twentieth century, the industrial sector introduced a new manufacturing method known as additive manufacturing, alongside traditional methods such as subtractive, joining, dividing, and transformative manufacturing. Recently, additive manufacturing technology has become increasingly competitive among these traditional methods due to its unique characteristics and the rapid development of its applications and features. The goal of the current study was to develop a method that enables users to make informed decisions regarding the most appropriate manufacturing method (i.e., additive or subtractive) for producing specific parts. The selection of the appropriate manufacturing method is complex and often relies on subjective judgment or experience, which can lead to suboptimal decisions. This study used part complexity as a basis for determining the most suitable manufacturing method for a specific part. Initially, the study identified factors that affect machining time from the literature, such as pocket internal small radius corners, thin walls, and 3D form surfaces. Actual manufacturing time, which is a reliable indicator of overall machining difficulty, was used along with the identified factors to develop a model that can predict part complexity using multiple regression with 54 parts as training data. The model was successfully validated by applying it to 31 parts as test data. Subsequently, the study developed a decision model that used the part complexity model and shape volume as factors to decide between additive and subtractive methods. The results show that these factors are critical in making the decision. The study also tested how production volume impacts the decision and found that it significantly shifts the choice between these technologies.22 0Item Restricted Automated Process Planning for Five-Axis Additive Manufacturing(Oregon State University, 2024-06-14) Alonayni, Ghazi Mohammed H; Campbell, Matthew I.Five-axis additive manufacturing provides a higher surface quality and needs less support than conventional three-axis machines. Automating the planning process for five-axis additive manufacturing could revolutionize manufacturing processes across industries. However, the increase in complexity creates challenges in automating the process planning. Thus, investigating new approaches to automate process planning could increase its adaptation as an innovative method for creating intricate 3D parts with high surface quality and minimal support. This thesis presents three methods to automate the process planning by analyzing the printing parts. The first method optimized the build orientation based on three objectives: support volume, surface quality, and print stability. The Pareto frontier solves the multi-objective optimization, finding the non-dominated orientations. The second proposed method is developing a new slicing technique using quadric surface fitting. The method is designed to fit sample points, solving the least squares problem with the Levenberg-Marquardt algorithm. Additionally, the surface orientation of a printing part is considered in the optimization. The optimization starts from a flat plane and changes as the printing layers progress to follow a part’s curvature. The result of this optimization is a list oflayers that are derived from the fitted quadric surfaces. In the last method, we developed an approach to optimize the placement of printing parts in a multi-part process. The presented method uses a part’s convex hull of a contacting layer with the build print to generate search candidates. We solve a multi-objective optimization, which maximizes the number of parts and surface quality and minimizes support. The outcomes of the third research are the non-dominated candidates. The proposed methods are applied to different 3D parts that vary in complexity. The proposed methods automate the process planning for five-axis additive manufacturing.29 0Item Restricted INVESTIGATION OF MEDIUM AND HIGH STRENGTH ALUMINUM ALLOY VIA DIRECT LASER METAL DEPOSITION(Wayne State University, 2024-03-06) Alrehaili, Husam; Wu, Xin; Almubarak, YaraAluminum (Al), for its excellent strength-to-weight ratio, offers lightweight material replacement in many automotive, aerospace, and other industrial applications. The demand for additive manufacturing AM-specific Al alloys is expected to overtake the demand for Die-Cast alloys and different types of alloys within the next five years. However, the processing of medium and high strength Al alloys by additive manufacturing (AM) has been limited due to challenges inherited within the AM process and alloy chemistry. As a result, in the 2020 annual Aluminum Association report, only 22 Al alloys are registered for AM compared to 560 wrought Al alloys. The conventional alloy design and development cycles require extensive iterations and resources during the initial stage, which are deemed to be inefficient. This research employed Laser Metal Deposition (LMD) as a versatile technique for alloy development. A new high-throughput alloy design and development methodology using LMD was presented and used for more efficient full-cycle data collection, feedback, and analysis. In addition, this methodology was used to investigate the microstructure evolution during the high cooling rate caused by the rapid solidification during AM. A new fundamental understanding of the effect of rapid solidification on the non-equilibrium phase transformation was revealed for hypo-eutectic binary Al-xSi alloys using the newly proposed high-throughput alloy design and development methodology. It was found that the volume fraction of the Al-Si eutectic phase during the non-equilibrium solidification decreased compared to the calculated equilibrium phase, resulting in a shift of the eutectic point in the phase diagram. The eutectic point in the non-equilibrium Al-Si phase diagram is estimated to be around Al-24.8 wt. %Si compared to Al-12.6 wt. %Si wt.% in the equilibrium phase diagram. In addition, the size and morphology of Si particles observed in the microstructures varied based on the location of the microstructures. In the second part of this dissertation, the microstructural evolution, and mechanical properties of an alloy from the ternary Al-Mg-Si (Cu), Al6000’s series, alloy system that is widely used in automotive applications was studied in detail. Two deposition strategies, hatch and circular patterns, were investigated to identify the effect of deposition strategy on crack formation. The cracking in Al6000’s series processed by the LMD process was successfully mitigated for the first time for AA6111 using a circular pattern deposition strategy. This strategy offered a more consistent cooling rate, resulting in less residual stresses accumulating in the material upon solidification. Furthermore, a comprehensive comparative study for AA6111 was conducted for AM fabricated samples and the conventional Direct Chill (DC) Casting component during a multi-stage rolling and heat treatment procedure. From the thermodynamic simulation, the non-equilibrium phase diagram for the AM processed AA6111 suggested that the freezing range of the alloy is extended by 100 oC compared to the equilibrium phase diagram of DC cast material. In addition, a secondary intermetallic phase rich in Fe, Si, and Mn was predicted for both AM and DC cast material, which was confirmed from the observation during the microstructure evolution study. This intermetallic phase contributes to the solid solution's strengthening of the AA6111. However, the size and morphology of these particles vary from one material to the other during the rolling and heat treatment procedure. The mechanical properties of AM AA6111 were similar to DC cast in rolled condition. The DC cast material showed around 10% more than AM regarding yield and ultimate tensile strength of 226.7 and 270.6 MPa, respectively. The AM AA6111 yield and ultimate tensile strength were 204.4 and 249.3 MPa, respectively. The discrepancy in the mechanical properties of Am and DC cast AA6111 is believed to be due to the difference in the Fe and Mn concentration between DC and AM compositions. This variation led to a lower concentration of intermetallic phases in the AM sample. Overall, the proposed high-throughput alloy design and development methodology using LMD allowed for more insight into the behavior and overall performance of the materials. A new fundamental knowledge of the effect of the AM process was revealed and studied from the manufacturing process and alloy chemistry perspectives.28 0Item Restricted Heat-Assisted Additive Manufacturing and Post-Heat Treatment of Inconel Supper Alloy: Investigating the Microstructure and Mechanical Properties(Saudi Digital Library, 2023) Almotari, Abdalmageed; Qattawi, AlaRecently, additive manufacturing (AM) has gained attention in the global manufacturing industry. The advantages are derived from the fact that it is a powder-based manufacturing process. The AM process enables the fabrication of complex parts that can be manufactured at a lower cost. This approach allows on-demand production, minimal structural limitations, and custom design. Many industries are concerned about the reliability and durability of AM metallic parts. The properties of the materials are not entirely known, and imperfections resulting from the production process are frequently detected, which lowers the performance of the material. Consequently, many studies have been conducted on the microstructures and mechanical properties of materials produced by AM. With recent advances in AM over the past decade and the introduction of high lasers and higher-quality raw materials, AM can produce functioning components with high mechanical performance. The manufacturing and post-fabrication processing conditions, in addition to post-heat treatments, strongly influence the microstructure and mechanical characteristics of additively manufactured components. Metal components are affected by the manufacturing orientation, such as the laser power, laser scanning speed, and powder layer thickness. Anisotropic mechanical behaviors, such as tensile strength and stiffness in additively manufactured components, are caused by the directed fabrication method and thermal history, which provide a microstructure different from that anticipated in traditional production. In addition, additively manufactured components are unpredictable because of imperfections generated by the unmelted powder or entrapped gases during manufacturing. This dissertation investigates the influence of various processing factors on the microstructure and mechanical behavior of additively manufactured components. In addition, a better understanding of how modified heat treatment and building process parameters affect the mechanical behavior and microstructure and how to account for them when designing products may lead to more durable and reliable components. The layer-by-layer manufacturing approach intrinsic to AM permits a heat input. Therefore, the thermal gradient and solidification rates vary throughout the process, resulting in changing solidification conditions and thus various solidification microstructures. The processing parameters used during fabrication and post-processing significantly affect the microstructure and mechanical performance of the additively manufactured parts. The first objective of this investigation was to study the influence of different processing variables using heat-assisted AM on the microstructure and mechanical performance of IN718 additively manufactured components. The second objective of this study was to optimize the post-heat treatments for IN 718 materials fabricated by AM. The third objective is to model the combined effect of heat-assisted AM and post-heat treatments on the precipitates δ, γ', and γ'' using Neural Network.30 0Item Restricted DESIGN FOR ADDITIVE MANUFACTURING POST-PROCESSING: DEVELOPING GUIDELINES AND BEST PRACTICES FOR DIGITAL MANUFACTURING CHAINS(Saudi Digital Library, 2023-09-29) Alsalman, Ahmed; Tammas-Williams, SamAdditive manufacturing, a transformative paradigm within modern manufacturing, holds the promise of intricate, efficient, and cost-effective production processes. This dissertation embarks on an in-depth exploration of additive manufacturing, addressing its multifaceted dimensions, challenges, and potential. The overarching objective is to synthesize pragmatic guidelines that optimize additive manufacturing practices from design to post-processing. The research commences with a comprehensive literature review that surveys the landscape of additive manufacturing, revealing gaps in understanding and knowledge. It proceeds to a series of experimental investigations, including case studies, designed to illuminate the complexities and advantages inherent in additive manufacturing. Guided by a mixed-method approach, the study delves into topics ranging from design considerations to post-processing methodologies, leveraging insights from industry collaboration. The culmination of this research is the formulation of comprehensive guidelines that navigate additive manufacturing's intricacies. These guidelines encompass design principles, printer selection, material utilization, and post-processing efficiency. While not universally exhaustive, they serve as robust decision-making tools, bridging the gap between theoretical knowledge and practical application. Contributions of this study extend to various industries, offering insights that foster additive manufacturing's effective integration. By addressing challenges specific to Design for Additive Manufacturing (DfAM) and Design for Additive Post-Processing (DfAPP), industries can navigate the complexities of additive manufacturing with greater precision. The guidelines proposed herein advocate a proactive approach, optimizing manufacturing practices for efficiency, cost-effectiveness, and product quality enhancement. Despite its contributions, this research acknowledges inherent limitations, including experimental constraints and the evolving nature of technology. Thus, future research avenues beckon, from advanced post-processing techniques to tailored guidelines for specific industries. As the additive manufacturing landscape evolves, ongoing research endeavors will be critical to ensuring that guidelines remain adaptive and effective. In essence, this dissertation encapsulates a journey through additive manufacturing's landscape, resulting in a set of guidelines that empower industries to leverage this transformative technology. As the manufacturing realm evolves into a digital era, characterized by precision and innovation, the guidelines proposed here stand as an essential compass, guiding industries toward optimal additive manufacturing practices.30 0