7 research outputs found
Failure mechanics of fused filament fabricated nylon/carbon reinforced composites
No full textThis work focuses on understanding the failure mechanisms of nylon-reinforced chopped carbon fiber (Onyx) composite and its reinforcement with carbon fiber printed using different infill patterns, i.e., solid fill, honeycomb, and triangular via fused filament fabrication (FFF) to enhance the sustainable manufacturing processes. The solid fill with carbon fiber reinforcement showcased a maximum tensile strength and flexural strength of ~ 300 MPa and ~ 22 MPa which were more than twice that of non-reinforced composites with fiber pull-out and layer debonding as predominant failure mechanisms. On the other hand, non-reinforced samples indicated matrix debonding as predominant failure behavior. The solid fill samples illustrated a lower failure mechanism owing to their higher bonding between each layer with limited voids whereas honeycomb and triangular samples failed faster due to the high number of voids limiting their bonding behavior. Furthermore, the load transfer capacity of honeycomb and triangular infill composites was limited due to reduced adhesion between the layers. Although the mechanical properties of onyx-based composites do not make them suitable for structural applications, the fused filament fabrication approach makes onyx a potential material for internal non-loading structures with complex geometries
A comparative analysis of mechanical and surface properties of FCC lattice in FFF and MJF based additive manufacturing
No full textModelling Heat Transfer in an Extruder for Recycling Plastics into Filaments for use in Additive Manufacturing
No full textGlobal production of plastic increased by 500% over the last 30 years and it is expected to continue to grow to 850 million tons/year by 2050. Plastic use results in a substantial environmental burden due to both land and water pollution as plastics take 10 to 450 years to decompose in landfills. This has resulted in increased calls for innovative ways to recycle plastics, one of which is a decentralised solution where wasted plastics are recycled into filaments for 3D printing. This has been identified as a promising solution, especially for low-income communities in the global south where waste management infrastructure is inadequate. However, studies have highlighted the need for more research and development in the extruder design and operation, especially in terms of optimising temperature distribution and the cooling rate in order to prevent poor filament quality and inconsistent filament diameter. This paper describes the modelling of the temperature distribution and cooling rate of an extruder. The innovation is that the extruder is designed to be built and operated in low-income settings of the global south using locally available materials and skills. The aim of the work is to develop a mathematical model for evaluating the thermal distribution in the extruder as well as optimise the cooling rate conditions. The model is useful for optimising the operating conditions such as ambient temperature, extrusion temperature, extrusion speed, cooling rate and spooling mechanism
Optimizing tibia implants : comparative study of lattice designs and material performance under gait cycles
No full textThis study advances orthopaedic implant design by examining the impact of lattice structures on gait cycles and integrating biomimicry principles for superior patient outcomes. Using Finite Element Analysis (FEA), three lattice designs; Face Centred Cubic (FCC), Body Centred Cubic (BCC), and a hybrid Face-Body Centred Cubic (FBCC) were evaluated with materials including Ni-Ti Shape Memory Alloy, TNTZ Alloy, and AZ91D Alloy for its suitability in orthopaedic implants. AZ91D emerged as the optimal material based on compression analysis, offering the best balance of strength and weight. Tibia bone implants made from AZ91D were tested under various gait cycle conditions, including loading-level knee bending, 20% bending, and 30% bending, where the FBCC structure outperformed others due to its enhanced load transfer capabilities. Porosity effects were analysed by varying strut diameters between 0.3 mm and 0.6 mm, resulting in a 40% stiffness difference compared to natural bone, affirming its suitability for biomimetic applications. This innovative approach achieves an ∼86% weight reduction compared to titanium-based implants, significantly enhancing comfort, reducing physical strain, and improving mobility for amputees. By leveraging advanced topology optimisation and material science, this research provides valuable insights into lightweight and high-performance orthopaedic implant development
Experimental and numerical analysis of 3D-printed pure PLA and ceramic-reinforced PLA multilayered composites
No full textFused Deposition Modeling (FDM) is a remarkable manufacturing method that helps us to produce such complex structures without the need for extra components or parts as required by most other manufacturing processes. This research article has focused on 3D-printed multi-layered polymer composite materials for various kinds of biomedical applications. In this research investigation, polylactic acid (PLA) is considered an alternative to the existing material in biomedical applications. In addition, for further improvement of the mechanical performance of PLA composite structures, ceramic-reinforced PLA (CRPLA) filament materials have been utilized to be multilayered with pure PLA materials. Ceramic particles have proved to enhance the mechanical and thermal properties of polymer composites. The tensile, compression, and flexural strength of 3D-printed pure PLA, ceramic composite, and multilayered laminates were evaluated experimentally, which was validated by FE simulation analysis. The results concluded that the tensile, flexural, and compressive strengths of multilayered 3D-printed composite laminates were increased by 28.9%, 5.9%, and 16.3%, respectively, compared with pure PLA-printed laminates. Scanning electron microscopy (SEM) has been utilized to investigate the fractography analysis of multilayered composite laminates. Moreover, thermal characterization has been done by using differential scanning calorimetry (DSC) analysis.</p
A review of current challenges and prospects of magnesium and its alloy for bone implant applications
No full textMedical application materials must meet multiple requirements, and the designed implant must mimic the bone structure in shape and support the formation of bone tissue (osteogenesis). Magnesium (Mg) alloys, as a “smart” biodegradable material and as “the green engineering material in the twenty-first century”, have become an outstanding bone implant material due to their natural degradability, smart biocompatibility, and desirable mechanical properties. Magnesium is recognised as the next generation of orthopaedic appliances and bioresorbable scaffolds. At the same time, improving the mechanical properties and corrosion resistance of magnesium alloys is an urgent challenge to promote the application of magnesium alloys. Nevertheless, the excessively quick deterioration rate generally results in premature mechanical integrity disintegration and local hydrogen build-up, resulting in restricted clinical bone restoration applicability. The condition of Mg bone implants is thoroughly examined in this study. The relevant approaches to boost the corrosion resistance, including purification, alloying treatment, surface coating, and Mg-based metal matrix composite, are comprehensively revealed. These characteristics are reviewed to assess the progress of contemporary Mg-based biocomposites and alloys for biomedical applications. The fabricating techniques for Mg bone implants also are thoroughly investigated. Notably, laser-based additive manufacturing fabricates customised forms and complicated porous structures based on its distinctive additive manufacturing conception. Because of its high laser energy density and strong controllability, it is capable of fast heating and cooling, allowing it to modify the microstructure and performance. This review paper aims to provide more insight on the present challenges and continued research on Mg bone implants, highlighting some of the most important characteristics, challenges, and strategies for improving Mg bone implants.</p
A review of current challenges and prospects of magnesium and its alloy for bone implant applications
No full textThe file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Medical application materials must meet multiple requirements, and the designed implant must mimic the bone structure in shape and support the formation of bone tissue (osteogenesis). Magnesium (Mg) alloys, as a “smart” biodegradable material and as "the green engineering material in the 21st century", have become an outstanding bone implant material due to their natural degradability, smart biocompatibility, and desirable mechanical properties. Magnesium is recognized as the next generation of orthopaedic appliances and bioresorbable scaffolds. At the same time, improving the mechanical properties and corrosion resistance of magnesium alloys is an urgent challenge to promote the application of magnesium alloys. Regardless, the excessively quick deterioration rate generally results in premature mechanical integrity disintegration and local hydrogen build-up, resulting in restricted clinical bone restoration applicability. The condition of Mg bone implants is thoroughly examined in this study. The relevant approaches to boost the corrosion resistance, including purification, alloying treatment, surface coating, and Mg-based metal matrix composite, are comprehensively revealed. These characteristics are reviewed in order to assess the progress of contemporary Mg-based biocomposites and alloys for biomedical applications. The fabricating techniques for Mg bone implants also are thoroughly investigated. Notably, laser-based additive manufacturing fabricates customised forms and complicated porous structures based on its distinctive additive manufacturing conception. Because of its high laser energy density and strong controllability, it is capable of fast heating and cooling, allowing it to modify the microstructure and performance. This review paper aims to provide more insight on the present challenges and continued research on Mg bone implants, highlighting some of the most important characteristics, challenges, and strategies for improving Mg bone implants
