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Janbaz, S. (author), Hedayati, R. (author), Zadpoor, A.A. (author)Nature uses various activation mechanisms to program complex transformations in the shape and functionality of living organisms. Inspired by such natural events, we aimed to develop initially flat (i.e. two-dimensional) programmable materials that, when triggered by a stimulus such as temperature, could self-transform their shape into a complex...journal article 2016
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Hedayati, R. (author), Sadighi, M. (author), Mohammadi-Aghdam, M. (author), Zadpoor, A.A. (author)Honeycomb structures have found numerous applications as structural and biomedical materials due to their favourable properties such as low weight, high stiffness, and porosity. Application of additive manufacturing and 3D printing techniques allows for manufacturing of honeycombs with arbitrary shape and wall thickness, opening the way for...journal article 2016
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Hedayati, R. (author), Hosseini-Toudeshky, H (author), Sadighi, M. (author), Mohammadi-Aghdam, M. (author), Zadpoor, A.A. (author)The mechanical behavior of additively manufactured porous biomaterials has recently received increasing attention. While there is a relatively large body of data available on the static mechanical properties of such biomaterials, their fatigue behavior is not yet well-understood. That is partly because systematic study of the fatigue behavior...journal article 2016
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Zadpoor, A.A. (author), Hedayati, R. (author)Recent developments in additive manufacturing techniques have motivated an increasing number of researchers to study regular porous biomaterials that are based on repeating unit cells. The physical and mechanical properties of such porous biomaterials have therefore received increasing attention during recent years. One of the areas that have...journal article 2016
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Hedayati, R. (author), Sadighi, M. (author), Mohammadi-Aghdam, M (author), Zadpoor, A.A. (author)Honeycombs resemble the structure of a number of natural and biological materials such as cancellous bone, wood, and cork. Thick honeycomb could be also used for energy absorption applications. Moreover, studying the mechanical behavior of honeycombs under in-plane loading could help understanding the mechanical behavior of more complex 3D...journal article 2016
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Hedayati, R. (author), Sadighi, M. (author)Today, interconnected open-cell porous structures made of titanium and its alloys are replacing the prevalent solid metals used in bone substitute implants. The advent of additive manufacturing techniques has enabled manufacturing of open-cell structures with arbitrary micro-structural geometry. In this paper, rhombic dodecahedron structures...journal article 2016
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Hedayati, R. (author), Sadighi, M (author), Mohammadi-Aghdam, M (author), Zadpoor, A.A. (author)Additively manufacturing (AM) techniques make it possible to fabricate open-cell interconnected structures with precisely controllable micro-architectures. It has been shown that the morphology, pore size, and relative density of a porous structure determine its macro-scale homogenized mechanical properties and, thus, its biological performance...journal article 2017
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Hedayati, R. (author), Janbaz, S. (author), Sadighi, M. (author), Mohammadi-Aghdam, M. (author), Zadpoor, A.A. (author)Although the initial mechanical properties of additively manufactured porous biomaterials are intensively studied during the last few years, almost no information is available regarding the evolution of the mechanical properties of implant-bone complex as the tissue regeneration progresses. In this paper, we studied the effects of tissue...journal article 2017
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Hedayati, R. (author), Leeflang, M.A. (author), Zadpoor, A.A. (author)Mechanical metamaterials exhibit unusual mechanical properties that originate from their topological design. Pentamode metamaterials are particularly interesting because they could be designed to possess any thermodynamically admissible elasticity tensor. In this study, we additively manufacture the metallic pentamode metamaterials from a...journal article 2017
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Mirzaali, Mohammad J. (author), Hedayati, R. (author), Vena, P. (author), Vergani, L. (author), Strano, M. (author), Zadpoor, A.A. (author)The elastic properties of mechanical metamaterials are direct functions of their topological designs. Rational design approaches based on computational models could, therefore, be used to devise topological designs that result in the desired properties. It is of particular importance to independently tailor the elastic modulus and Poisson's...journal article 2017
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Hedayati, R. (author), Amin Yavari, S. (author), Zadpoor, A.A. (author)Additively manufactured porous titanium implants, in addition to preserving the excellent biocompatible properties of titanium, have very small stiffness values comparable to those of natural bones. Although usually loaded in compression, biomedical implants can also be under tensional, shear, and bending loads which leads to crack initiation...journal article 2017
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Hedayati, R. (author), Sadighi, M. (author), Mohammadi-Aghdam, M (author), Hosseini-Toudeshky, H (author)Additive manufacturing techniques have made it possible to create open-cell porous structures with arbitrary micro-geometrical characteristics. Since a wide range of micro-geometrical features is available for making an implant, having a comprehensive knowledge of the mechanical response of cellular structures is very useful. In this study,...journal article 2018
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Hedayati, R. (author), Mirzaali, Mohammad J. (author), Vergani, L. (author), Zadpoor, A.A. (author)Mechanical metamaterials are a sub-category of designer materials where the geometry of the material at the small-scale is rationally designed to give rise to unusual properties and functionalities. Here, we propose the concept of "action-at-a-distance" metamaterials where a specific pattern of local deformation is programmed into the fabric...journal article 2018
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Hedayati, R. (author), Ahmadi, S.M. (author), Lietaert, K. (author), Tümer, N. (author), Li, Y (author), Amin Yavari, S. (author), Zadpoor, A.A. (author)Magnesium and its alloys have the intrinsic capability of degrading over time in vivo without leaving toxic degradation products. They are therefore suitable for use as biodegradable scaffolds that are replaced by the regenerated tissues. One of the main concerns for such applications, particularly in load-bearing areas, is the sufficient...journal article 2018
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Ahmadi, S.M. (author), Hedayati, R. (author), Li, Y (author), Lietaert, K. (author), Tümer, N. (author), Fatemi, A. (author), Rans, C.D. (author), Pouran, B. (author), Weinans, Harrie (author), Zadpoor, A.A. (author)Additive manufacturing (AM) techniques enable fabrication of bone-mimicking meta-biomaterials with unprecedented combinations of topological, mechanical, and mass transport properties. The mechanical performance of AM meta-biomaterials is a direct function of their topological design. It is, however, not clear to what extent the material type...journal article 2018
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Hedayati, R. (author), Hosseini-Toudeshky, H. (author), Sadighi, M. (author), Mohammadi-Aghdam, M. (author), Zadpoor, A.A. (author)Advances in additive manufacturing (AM) techniques have enabled fabrication of highly porous titanium implants that combine the excellent biocompatibility of bulk titanium with all the benefits that a regular volume-porous structure has to offer (e.g. lower stiffness values comparable to those of bone). Clinical application of such...journal article 2018
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Hedayati, R. (author), Sadighi, M. (author)Metal foams are cellular solids that show some unique properties which cannot be found in other natural or human-made materials. While the impact characteristics of closed-cell foams under static and impact loadings appear to be well-studied in the literature, the impact behaviour of open-cell foams is not yet well-understood. In this study,...journal article 2018
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Hedayati, R. (author), Rubio Carpio, A. (author), Luesutthiviboon, S. (author), Ragni, D. (author), Avallone, F. (author), Casalino, D. (author), van der Zwaag, S. (author)Studies on porous trailing edges, manufactured with open-cell Ni-Cr-Al foams with sub-millimeter pore sizes, have shown encouraging results for the mitigation of turbulent boundary-layer trailing-edge noise. However, the achieved noise mitigation is typically dependent upon the pore geometry, which is fixed after manufacturing. In this study,...journal article 2019
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Hedayati, R. (author), Jedari Salami, S. (author), Li, Y. (author), Sadighi, M. (author), Zadpoor, A.A. (author)We study a special class of mechanical metamaterials, namely lattices, based on beams (struts) with nonuniform cross sections, of which pentamode mechanical metamaterials are a special case. Five symmetric beam types including simple cylinder, concave double cone, convex double cone, concave hyperbolic, and convex hyperbolic are considered....journal article 2019
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SoltanRezaee, Masoud (author), Bodaghi, Mahdi (author), Farrokhabadi, Amin (author), Hedayati, R. (author)The main objective of this research is to provide a general nonlinear model of adjustable piezoelectric microwires with the ability to tune the stability conditions. In order to increase the controllability and improve system characteristics, only a part of the substrate is electrostatically actuated and the piezoelectric voltage is also...journal article 2019