60 research outputs found

    FEM based investigation on thrust force and torque during Al7075-T6 drilling

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    As modern industry advances, the demand for more time and cost effective machining is rising. In order to achieve high levels of standard during machining it is necessary to employ sophisticated techniques for precise prediction of various important parameters that relate to the machining processes. Such technique is the implementation of finite element modelling (FEM) which can become a valuable tool for researchers and industry engineers alike. In this work, the 3D modelling of Al7075-T6 drilling process with solid carbide tooling is being presented. DEFORM3Dâ„¢ finite element analysis (FEA) software was utilized for simulating the drilling process based on frequently used cutting conditions; cutting speed of 100m/min and feed of 0.15mm/rev, 0.20mm/rev and 0.25mm/rev respectively. In order to approximate the complex phenomena that occur during drilling, the most critical factors were considered in the presented model such as the developed friction, heat transfer and damage interaction between the tool and the workpiece. Additionally, a validation of the generated results for thrust force and torque was performed by comparing the simulated results with experimental data. Three drilling experiments were carried out with the aid of a CNC machining center and a four component dynamometer in order to acquire the experimental values of thrust force and torque. Most of the simulations yielded results in accordance to the experimental ones with the agreement percentage reaching 95% in most cases for both the thrust force and torque, confirming the validity of the models and the accuracy of the simulated results

    Bottom-up development of nanoimprinted PLLA composite films with enhanced antibacterial properties for smart packaging applications

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    Altres ajuts: ICN2 is supported by the CERCA Program/Generalitat de Catalunya.In this work, polymer nanocomposite films based on poly(L-lactic acid) (PLLA) were reinforced with mesoporous silica nanoparticles, mesoporous cellular foam (MCF) and Santa Barbara amorphous-15 (SBA). PLLA is a biobased aliphatic polyester, that possesses excellent thermomechanical properties, and has already been commercialized for packaging applications. The aim was to utilize nanoparticles that have already been established as nanocarriers to enhance the mechanical and thermal properties of PLLA. Since the introduction of antibacterial properties has become an emerging trend in packaging applications, to achieve an effective antimicrobial activity, micro/nano 3D micropillars decorated with cone- and needle-shaped nanostructures were implemented on the surface of the films by means of thermal nanoimprint lithography (t-NIL), a novel and feasible fabrication technique with multiple industrial applications. The materials were characterized regarding their composition and crystallinity using Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD), respectively, and their thermal properties using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Their mechanical properties were examined by the nanoindentation technique, while the films' antimicrobial activity against the bacteria Escherichia coli and Staphylococcus aureus strains was tested in vitro. The results demonstrated the successful production of nanocomposite PLLA films, which exhibited improved mechanical and thermal properties compared to the pristine material, as well as notable antibacterial activity, setting new groundwork for the potential development of biobased smart packaging materials

    Beyond the walls: the design and development of the Petralona Cave virtual museum utilising 3D technologies

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    The Petralona Cave, which local inhabitants discovered by chance in 1959, is a remarkable natural and cultural landmark close to the village of Petralona, in the Chalkidiki peninsula of Greece. The site has gained global recognition for the discovery of a remarkably well-preserved Palaeolithic human skull, unearthed in 1960; it also holds archaeological and palaeontological significance. In this paper, the researchers introduce the Petralona Cave Virtual Museum: an innovative project whose mission is to increase public awareness and comprehension of the site. Our approach goes beyond mere replication of the physical museum located close to the cave; instead, the objective is to create an independent and comprehensive experience that is accessible to all visitors, irrespective of their ability to visit the site in person. Our methodology involved the documentation of the site and its history, analysis of user requirements, development of use cases to steer the design process, as well as architectural designs creation, itineraries and findings digitisation, and architectural structure finalisation. The Virtual Museum provides a well-organised frame structure that serves as an efficient gateway to the content, making navigation easy for visitors. Thanks to various presentation methods, including videos, high-quality images, interactive maps, animated content, interactive 3D models, plus searchable item libraries, among others, users are empowered to create a highly personalised navigation plan; thus the Virtual Museum experience is comparable to visiting the physical museum or cultural site. Cutting-edge digitisation techniques were employed to create highly detailed 3D models of the site. The Petralona Cave Virtual Museum is expected to offer an immersive experience, engaging diverse audiences; the interactive and educational exploration provides highly innovative access to archaeological knowledge. The visibility of the Petralona site is amplified and there is a significant contribution to knowledge dissemination about this important cultural heritage site

    Feasibility study on the vacuum infusion of composite-to-composite in-field repairs

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    OXYGEN PRESSURE REGULATOR DESIGN AND ANALYSIS THROUGH FINITE ELEMENT MODELING

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    Oxygen production centers produce oxygen in high pressure that needs to be defused. A regulator is designed and analyzed in the current paper for medical use in oxygen production centers. This study aims to design a new oxygen pressure regulator and perform an analysis using Finite Element Modeling in order to evaluate its working principle. In the design procedure,the main elements and the operating principles of a pressure regulator are taking into account. The regulator is designed and simulations take place in order to assessthe proposed design. Stress analysis results are presented for the main body of the regulator, as well as, flow analysis to determine some important flow characteristics in the inlet and outlet of the regulator

    Starch Sandstones in Building Bio-materials

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    A review of the recent literature shows that the use of more sustainable, eco-friendly recycled waste materials made from natural biopolymers is an important step of the planning process to reduce the environmental impacts of traditional building materials such as cement and concrete products. This study introduces the application of maize starch in the production of a novel biodegradable construction material. The samples prepared in this investigation were formed by heating a mixture of different proportions of starch, water and sand. The structural properties, morphology and chemical composition of materials were investigated by scanning electron microscopy (SEM) coupled with thermal gravimetric analysis (TGA). The structural characteristics and morphology of the study material to a certain extent resemble natural sandstones, the most common type of sedimentary rocks. Based on the uniaxial compressive strength classification schemes, comparing with the brittle deformation behavior of natural rocks, it can be considered that this material behaves as a polymer - matrix composite with a ductile - thermoplastic mechanical behavior

    Starch Sandstones in Building Bio-materials

    No full text
    A review of the recent literature shows that the use of more sustainable, eco-friendly recycled waste materials made from natural biopolymers is an important step of the planning process to reduce the environmental impacts of traditional building materials such as cement and concrete products. This study introduces the application of maize starch in the production of a novel biodegradable construction material. The samples prepared in this investigation were formed by heating a mixture of different proportions of starch, water and sand. The structural properties, morphology and chemical composition of materials were investigated by scanning electron microscopy (SEM) coupled with thermal gravimetric analysis (TGA). The structural characteristics and morphology of the study material to a certain extent resemble natural sandstones, the most common type of sedimentary rocks. Based on the uniaxial compressive strength classification schemes, comparing with the brittle deformation behavior of natural rocks, it can be considered that this material behaves as a polymer - matrix composite with a ductile - thermoplastic mechanical behavior
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