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    Depicting additive manufacturing from a global perspective; Using Cloud manufacturing paradigm for integration and collaboration

    , Article Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture ; Volume 229, Issue 12 , September , 2015 , Pages 2216-2237 ; 09544054 (ISSN) Valilai, O. F ; Houshmand, M ; Sharif University of Technology
    SAGE Publications Ltd  2015
    Globalization is one of the widely considered factors in today's manufacturing industries. This paradigm may be adopted for new technologies such as additive manufacturing. Additive manufacturing has been identified as an innovative manufacturing technology in recent years. The characteristics of this manufacturing technology, especially its support for quick design to manufacturing, have dominated it as an efficient generation of manufacturing techniques for today's global manufacturing paradigm. This article discusses the requirements and necessities of additive manufacturing with respect to a globalized perspective. Considering the two major requirements studied as integration of... 

    Plasticity in polymeric honeycombs made by photo-polymerization and nozzle based 3D-printing

    , Article Polymer Testing ; Volume 63 , 2017 , Pages 163-167 ; 01429418 (ISSN) Goodarzi Hosseinabadi, H ; Bagheri, R ; Avila Gray, L ; Altstädt, V ; Drechsler, K ; Sharif University of Technology
    Study of the plastic deformation in polymeric honeycombs can pave the way for understanding the deformation localization in more complex cellular structures, which have received progressive attention in the past few years. This study compares the strain localization in deforming honeycombs made by two cost-effective 3D-printing technologies. Hexagonal honeycombs and their unit cell models were 3D-printed by both PolyJet™, using a photo-crosslinkable polymer, and fused deposition modeling (FDM) using a thermoplastic material. The state of the art digital image correlation (DIC) technique was employed as the experimental route in order to calculate the strain field during the deformation of... 

    Additive manufacturing of Ti–6Al–4V parts through laser metal deposition (LMD): Process, microstructure, and mechanical properties

    , Article Journal of Alloys and Compounds ; Volume 804 , 2019 , Pages 163-191 ; 09258388 (ISSN) Azarniya, A ; Colera, X. G ; Mirzaali, M. J ; Sovizi, S ; Bartolomeu, F ; St Weglowski, M. K ; Wits, W. W ; Yap, C. Y ; Ahn, J ; Miranda, G ; Silva, F. S ; Madaah Hosseini, H. R ; Ramakrishna, S ; Zadpoor, A. A ; Sharif University of Technology
    Elsevier Ltd  2019
    As one of the most important additive manufacturing (AM) techniques, laser metal deposition (LMD) has been extensively studied specially during the last few years. Similar to other AM techniques, the quality of LMD parts is highly dependent on the processing parameters that need to be optimized so as to obtain geometrically accurate parts as well as favorable microstructures and, thus, mechanical properties. The present review paper therefore aims to present a critical analysis and overview of the relationship between processing parameters, microstructure, and mechanical properties of LMD components made from the Ti–6Al–4V alloy. Moreover, we discuss the applications of LMD parts in the... 

    A framework for multi-objective optimisation of 3D part-build orientation with a desired angular resolution in additive manufacturing processes

    , Article Virtual and Physical Prototyping ; Volume 14, Issue 1 , 2019 , Pages 19-36 ; 17452759 (ISSN) Golmohammadi, A. H ; Khodaygan, S ; Sharif University of Technology
    Taylor and Francis Ltd  2019
    In additive manufacturing processes, the part build orientation (PBO) is one of the most important factors that can affect the characteristics of the quality product such as the amount of support structure and the surface roughness. In most previous methods, the optimal PBO cannot be determined with high precision and accuracy in 3D space. In this paper, to find the precise and accurate optimal PBO with a desired angular accuracy, a new Taguchi-based method, called the Zooming-Taguchi method, is proposed. The proposed simulation-based method can precisely find the optimal PBO in absence of the noise effects. In order to find the optimal PBO with the desired angular resolution, the zooming... 

    An efficient scanning algorithm for improving accuracy based on minimising part warping in selected laser sintering process

    , Article Virtual and Physical Prototyping ; Volume 14, Issue 1 , 2019 , Pages 59-78 ; 17452759 (ISSN) Manshoori Yeganeh, A ; Movahhedy, M. R ; Khodaygan, S ; Sharif University of Technology
    Taylor and Francis Ltd  2019
    In the selective laser sintering (SLS) method, layers of powder are scanned by a laser beam and sintered. The thermal gradients created by laser heating and the subsequent cooling of the sintered sections results in thermal stresses and part warping in the final part. Thermal gradients are dependent on the scanning algorithm, in particular, the scan vector length. In this work, an efficient scanning algorithm for the SLS process is presented with the aim to minimise the part warping in the final part due to thermally induced residual stresses, while maintaining the production time at a minimum. The proposed algorithm is implemented in a finite element simulation and scanning parameters... 

    Microengineered poly(HEMA) hydrogels for wearable contact lens biosensing

    , Article Lab on a Chip ; Volume 20, Issue 22 , 2020 , Pages 4205-4214 Chen, Y ; Zhang, S ; Cui, Q ; Ni, J ; Wang, X ; Cheng, X ; Alem, H ; Tebon, P ; Xu, C ; Guo, C ; Nasiri, R ; Moreddu, R ; Yetisen, A. K ; Ahadian, S ; Ashammakhi, N ; Emaminejad, S ; Jucaud, V ; Dokmeci, M.R ; Khademhosseini, A ; Sharif University of Technology
    Royal Society of Chemistry  2020
    Microchannels in hydrogels play an essential role in enabling a smart contact lens. However, microchannels have rarely been created in commercial hydrogel contact lenses due to their sensitivity to conventional microfabrication techniques. Here, we report the fabrication of microchannels in poly(2-hydroxyethyl methacrylate) (poly(HEMA)) hydrogels that are used in commercial contact lenses with a three-dimensional (3D) printed mold. We investigated the corresponding capillary flow behaviors in these microchannels. We observed different capillary flow regimes in these microchannels, depending on their hydration level. In particular, we found that a peristaltic pressure could reinstate flow in... 

    Ferrofluid droplet formation from a nozzle using alternating magnetic field with different magnetic coil positions

    , Article Journal of Magnetism and Magnetic Materials ; Volume 498 , 2020 Favakeh, A ; Bijarchi, M. A ; Shafii, M. B ; Sharif University of Technology
    Elsevier B.V  2020
    Ferrofluid has been used in many fields, such as microfluidics, droplet formation, and heat transfer, due to its potential to be attracted in the presence of a magnetic field. Droplet formation, itself, has many applications such as emulsions, 3D micro-printers, MEMS, and electro-sprays. In this study, the mechanism of ferrofluid droplet formation from the nozzle in the presence of an alternating magnetic field was investigated. The magnetic coil was fixed at different angles with respect to gravity and the effect of the alternating magnetic field and the angle of the magnetic coil axis with respect to gravity on the produced droplet volume, satellite droplet, and droplet formation frequency... 

    Hybrid anisotropic pentamode mechanical metamaterial produced by additive manufacturing technique

    , Article Applied Physics Letters ; Volume 117, Issue 6 , 2020 Mohammadi, K ; Movahhedy, M. R ; Shishkovsky, I ; Hedayati, R ; Sharif University of Technology
    American Institute of Physics Inc  2020
    Pentamode metamaterials are a type of extremal designer metamaterials, which are able to demonstrate extremely high rigidity in one direction and extremely high compliance in other directions. Pentamodes can, therefore, be considered as building blocks of exotic materials with any arbitrarily selected thermodynamically admissible elasticity tensor. The pentamode lattices can then be envisioned to be combined to construct intermediate extremal materials, such as quadramodes, trimodes, and bimodes. In this study, we constructed several primary types of anisotropic pentamode lattices (with midpoint positioning of 10%, 15%, 20%, 25%, 30%, 35%, and 42% of the main unit cell diagonal) and then... 

    A 3D-printed hybrid nasal cartilage with functional electronic olfaction

    , Article Advanced Science ; Volume 7, Issue 5 , 2020 Jodat, Y. A ; Kiaee, K ; Vela Jarquin, D ; De la Garza Hernández, R. L ; Wang, T ; Joshi, S ; Rezaei, Z ; de Melo, B. A. G ; Ge, D ; Mannoor, M. S ; Shin, S. R ; Sharif University of Technology
    John Wiley and Sons Inc  2020
    Advances in biomanufacturing techniques have opened the doors to recapitulate human sensory organs such as the nose and ear in vitro with adequate levels of functionality. Such advancements have enabled simultaneous targeting of two challenges in engineered sensory organs, especially the nose: i) mechanically robust reconstruction of the nasal cartilage with high precision and ii) replication of the nose functionality: odor perception. Hybrid nasal organs can be equipped with remarkable capabilities such as augmented olfactory perception. Herein, a proof-of-concept for an odor-perceptive nose-like hybrid, which is composed of a mechanically robust cartilage-like construct and a biocompatible... 

    Fabrication of porosity-graded biocompatible structures by 3D printing of Co-Cr-Mo alloy

    , Article European Powder Metallurgy Congress and Exhibition, Euro PM 2007, Toulouse, 15 October 2007 through 17 October 2007 ; Volume 3 , 2007 , Pages 255-260 ; 9781899072293 (ISBN) Dourandish, M ; Simchi, A ; Godlinski, D ; Sharif University of Technology
    European Powder Metallurgy Association (EPMA)  2007
    Manufacturing of complex-shaped bimetals utilizing two-color powder injection molding (2C-PIM) and three-dimensional printing (3DP) processes, which basically involve sintering of a powder/binder mixture, has been attracted a great interest. This article addresses sintering of biocompatible Co-Cr-Mo alloy for manufacturing stepwise porosity-graded composite structures. Such composite structures provide strength at the core and a porous layer for the tissue growth. To evaluate the process, two grades of gas atomized Co-Cr-Mo powder with an average particle size of 19 and 63 μm were used. Isothermal and nonisothermal sintering behavior of the loose powders under hydrogen and argon atmospheres... 

    Colloidal particle reaction and aggregation control in the Electrohydrodynamic 3D printing technology

    , Article International Journal of Mechanical Sciences ; Volume 195 , 2021 ; 00207403 (ISSN) Mohammadi, K ; Movahhedy, M. R ; Khodaygan, S ; Sharif University of Technology
    Elsevier Ltd  2021
    The electrohydrodynamic (EHD) 3D printing technology is an Additive Manufacturing (AM) method that can be used in the manufacture of submicron-size structures. In this process, which is based on the formation of Taylor jet from a metallic ink, the investigation of particles reaction and aggregate formation in ink during printing is of great importance. In this paper, a new Finite Element model based on particle tracing in fluids is presented that couples the different physics that govern an EHD phenomenon. Vortex flow caused by boundary shear stress was observed in the ink jet; which was more like the Marangoni phenomenon in a stationary drop. By experimentally validating the presented model... 

    Advanced steel powder for direct metal laser sintering

    , Article European Powder Metallurgy Congress and Exhibition, Euro PM 2005, Prague, 2 October 2005 through 5 October 2005 ; Volume 3 , 2005 , Pages 35-40 ; 9781899072187 (ISBN) Petzoldt, F ; Pohl, H ; Simchi, A ; Alcantara, B ; Sharif University of Technology
    European Powder Metallurgy Association (EPMA)  2005
    Recent advances in material issues for Direct Metal Laser Sintering (DMLS) process are presented. The concept is to decrease the powder particle size with the aim of enhancing the sintering kinetics and improving the surface quality of the produced parts. The outcome is particularly suitable for overcoming existing limitations with the rapid tooling, e.g. manufacturing of mould inserts for injection moulding and die casting, by the DMLS process. The powder composition was adapted near to the conventional P/M steels in order to get identical properties with a favourable price. Such novel powder material provides an opportunity to considerably reduce the product development time for P/M... 

    Direct metal laser sintering of Fe-C-Cu steel powder

    , Article European Powder Metallurgy Congress and Exhibition, Euro PM 2005, Prague, 2 October 2005 through 5 October 2005 ; Volume 3 , 2005 , Pages 41-47 ; 9781899072187 (ISBN) Simchi, A ; Petzoldt, F ; Pohl, H ; European Powder Metallurgy Association ; Sharif University of Technology
    European Powder Metallurgy Association (EPMA)  2005
    Cu-alloyed sintered steels are one of the main product groups in ferrous powder metallurgy (P/M). To expand the application of P/M technology to different sectors of industry and to create new market, it is believed that rapid prototyping and short serial production of sintered parts for functional testing is important. In the present work, rapid prototyping of sintered Fe-C-Cu steel powders by direct metal laser sintering (DMLS) process was studied. Fe, Fe-0.8%C, Fe-2%Cu, Fe-4%Cu, Fe-0.8%C-2%Cu-0.35%P powders were laser sintered in widely varying conditions. The densification and microstructural features of the sintered parts were evaluated. The results revealed that rapid prototyping of... 

    Assessment of fiber-reinforcement and foam-filling in the directional energy absorption performance of a 3D printed accordion cellular structure

    , Article Composite Structures ; Volume 297 , 2022 ; 02638223 (ISSN) Farrokhabadi, A ; Mahdi Ashrafian, M ; Behravesh, A. H ; Kaveh Hedayati, S ; Sharif University of Technology
    Elsevier Ltd  2022
    This paper presents an evaluation of two distinct techniques to improve energy absorption capability of an accordion cellular structure with close-to-zero Poisson's ratio. For this purpose, fiber-reinforcement and foam-filling methods were employed to address the material enhancement and to obtain light and tough structures with high specific energy absorption. Employing an innovated additive manufacturing based on material extrusion process, specimens of glass fiber-reinforced PLA were produced in both in-plane directions to compare with the un-reinforced counterpart. In continue, some of the 3D printed samples were strengthened by means of polyurethane foam in their hollow structure. The... 

    Microfluidic-assisted fiber production: Potentials, limitations, and prospects

    , Article Biomicrofluidics ; Volume 16, Issue 6 , 2022 ; 19321058 (ISSN) Abrishamkar, A ; Nilghaz, A ; Saadatmand, M ; Naeimirad, M ; Demello, A. J ; Sharif University of Technology
    American Institute of Physics Inc  2022
    Besides the conventional fiber production methods, microfluidics has emerged as a promising approach for the engineered spinning of fibrous materials and offers excellent potential for fiber manufacturing in a controlled and straightforward manner. This method facilitates low-speed prototype synthesis of fibers for diverse applications while providing superior control over reaction conditions, efficient use of precursor solutions, reagent mixing, and process parameters. This article reviews recent advances in microfluidic technology for the fabrication of fibrous materials with different morphologies and a variety of properties aimed at various applications. First, the basic principles, as... 

    Developing an Off-the-Shelf microfluidic droplet generation device for cell encapsulation

    , Article Industrial and Engineering Chemistry Research ; Volume 61, Issue 30 , 2022 , Pages 10689-10699 ; 08885885 (ISSN) Hassani Gangaraj, M ; Shamloo, A ; Sharif University of Technology
    American Chemical Society  2022
    Droplet microfluidics is a platform of microfluidics in which two immiscible fluids are used to generate droplets for various biomedical applications. This platform introduces several advantages in applications such as cell lysis, cell culture, co-culture, and cell encapsulation. The most important issues regarding droplet generation devices are the fabrication complexity and maintenance of these devices. In this study, a simple and easy-to-fabricate microdroplet generator is designed and fabricated to resolve these issues. Furthermore, since this device is easy to fabricate and use, it can play a key role in the fabrication of medical devices for controlling infectious diseases in poor and... 

    Design and characterization of an orthotropic accordion cellular honeycomb as one-dimensional morphing structures with enhanced properties

    , Article Journal of Sandwich Structures and Materials ; Volume 24, Issue 3 , 2022 , Pages 1726-1745 ; 10996362 (ISSN) Farrokhabadi, A ; Ashrafian, M. M ; Fotouhi, M ; Sharif University of Technology
    SAGE Publications Ltd  2022
    This study develops the governing equations and characterizes the mechanical properties of a new orthotropic accordion morphing honeycomb structure containing periodic arrays of U-type beams reinforced with glass fibers. Castigliano’s second theorem is modified to develop the analytical equations to predict the deformation behavior of a single orthotropic ply under a combined axial, bending, and shear loadings. Accordingly, the elastic properties of the orthotropic structure including elastic stiffness, shear stiffness, and in-plane Poisson’s ratios are calculated by the developed equations. The honeycomb structure is manufactured by 3D printing, and the samples are subjected to tensile... 

    Effect of laser additive manufacturing parameters on hardness and geometry of Inconel 625 parts manufactured by direct laser metal deposition

    , Article Optik ; Volume 249 , 2022 ; 00304026 (ISSN) Nankali, M ; Akbari, J ; Moradi, M ; Malekshahi Beiranvand, Z ; Sharif University of Technology
    Elsevier GmbH  2022
    This research investigates the effect of process parameters on the geometry and properties of In625 parts, manufactured by the direct laser metal deposition (DLMD) process. For this purpose, eight parts, consisting of 5 layers on top of each other, were manufactured, and the effect of laser power, laser focal plane position, and scanning speed on the height, width, and surface smoothness of each of them was investigated using design of experiment (DOE). The experimental results showed that the height of the parts manufactured by 800 W/mm and 200 W/mm of energy density is 3.69 mm and 6.12 mm, respectively. The thickness of the parts manufactured by 80 W/mm and 200 W/mm of energy density is... 

    Production and characterization of Ti6Al4V/CaP nanocomposite powder for powder-based additive manufacturing systems

    , Article Powder Technology ; Volume 386 , 2021 , Pages 319-334 ; 00325910 (ISSN) Sayedain, S. S ; Ekrami, A ; Badrossamay, M ; Sharif University of Technology
    Elsevier B.V  2021
    Ti64/CaP nanocomposite powder was fabricated and characterized for use in powder-bed 3D printing. The microstructure and phase composition, morphology, particle size distribution, sphericity, flow behavior and dispersion of the as-fabricated particles on the building plate of the 3D printer were investigated. The results confirmed a uniform distribution of nanostructured calcium phosphate particles on the surface of primary Ti64 ones. Calcium phosphate appears as an octa-calcium phosphate phase. The morphology of the particles was shown as spherical, and their sphericity was better than the as-received Ti64 particles. The particle size distribution of nanocomposite powder indicated a smaller... 

    Fabrication of a highly ordered hierarchically designed porous nanocomposite via indirect 3D printing: Mechanical properties and in vitro cell responses

    , Article Materials and Design ; Volume 88 , 2015 , Pages 924-931 ; 02641275 (ISSN) Tamjid, E ; Simchi, A ; Sharif University of Technology
    Elsevier Ltd  2015
    Design and development of biodegradable scaffolds with highly uniform and controlled internal structure that stimulate tissue regeneration are the focus of many studies. The aim of this work is to apply a modified three-dimensional (3D) printing process to fabricate polymer-matrix composites with controlled internal architecture. Computationally-designed plaster molds with various pore sizes in the range of 300-800. μm were prepared by employing 3D printing of a water-based binder. The molds were converted to ε-polycaprolactone (PCL) and PCL/bioactive glass (BG) composite scaffolds by solvent casting and freeze drying methods. Optical and electron microscopy studies revealed that the pore...