Author
Ivan Giorgio
Other affiliations: Aeronáutica, Sapienza University of Rome
Bio: Ivan Giorgio is an academic researcher from University of L'Aquila. The author has contributed to research in topics: Finite element method & Dissipation. The author has an hindex of 39, co-authored 96 publications receiving 4266 citations. Previous affiliations of Ivan Giorgio include Aeronáutica & Sapienza University of Rome.
Papers
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TL;DR: In this article, the authors considered a discrete spring model for extensible beams and proposed a heuristic homogenization technique of the kind first used by Piola to formulate a continuum fully nonlinear beam model.
Abstract: The aim of this paper is to find a computationally efficient and predictive model for the class of systems that we call ‘pantographic structures’. The interest in these materials was increased by the possibilities opened by the diffusion of technology of three-dimensional printing. They can be regarded, once choosing a suitable length scale, as families of beams (also called fibres) interconnected to each other by pivots and undergoing large displacements and large deformations. There are, however, relatively few ‘ready-to-use’ results in the literature of nonlinear beam theory. In this paper, we consider a discrete spring model for extensible beams and propose a heuristic homogenization technique of the kind first used by Piola to formulate a continuum fully nonlinear beam model. The homogenized energy which we obtain has some peculiar and interesting features which we start to describe by solving numerically some exemplary deformation problems. Furthermore, we consider pantographic structures, find the corresponding homogenized second gradient deformation energies and study some planar problems. Numerical solutions for these two-dimensional problems are obtained via minimization of energy and are compared with some experimental measurements, in which elongation phenomena cannot be neglected.
333 citations
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University of L'Aquila1, University of the South, Toulon-Var2, Medical University of Warsaw3, Warsaw University of Technology4, University of California, Berkeley5, Sapienza University of Rome6, University of Sassari7, Roma Tre University8, University of Lyon9, Gdańsk University of Technology10, University of Kansas11, University of Catania12, University of Cagliari13, University of La Rochelle14, University of Lorraine15, Technical University of Berlin16, University of Paris17, Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institut18, Université Paris-Saclay19
TL;DR: P pantographic metamaterials undergo very large deformations while remaining in the elastic regime, are very tough in resisting to damage phenomena, and exhibit robust macroscopic mechanical behavior with respect to minor changes in their microstructure and micromechanical properties.
Abstract: In this paper, we account for the research efforts that have been started, for some among us, already since 2003, and aimed to the design of a class of exotic architectured, optimized (meta) materials. At the first stage of these efforts, as it often happens, the research was based on the results of mathematical investigations. The problem to be solved was stated as follows: determine the material (micro)structure governed by those equations that specify a desired behavior. Addressing this problem has led to the synthesis of second gradient materials. In the second stage, it has been necessary to develop numerical integration schemes and the corresponding codes for solving, in physically relevant cases, the chosen equations. Finally, it has been necessary to physically construct the theoretically synthesized microstructures. This has been possible by means of the recent developments in rapid prototyping technologies, which allow for the fabrication of some complex (micro)structures considered, up to now, to be simply some mathematical dreams. We show here a panorama of the results of our efforts (1) in designing pantographic metamaterials, (2) in exploiting the modern technology of rapid prototyping, and (3) in the mechanical testing of many real prototypes. Among the key findings that have been obtained, there are the following ones: pantographic metamaterials (1) undergo very large deformations while remaining in the elastic regime, (2) are very tough in resisting to damage phenomena, (3) exhibit robust macroscopic mechanical behavior with respect to minor changes in their microstructure and micromechanical properties, (4) have superior strength to weight ratio, (5) have predictable damage behavior, and (6) possess physical properties that are critically dictated by their geometry at the microlevel.
264 citations
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University of the South, Toulon-Var1, University of Paris2, University of L'Aquila3, Sapienza University of Rome4, Université Paris-Saclay5, Warsaw University of Technology6, University of Catania7, University of Stuttgart8, Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institut9, University of Sassari10, University of Kansas11, University of Paris-Sud12, Arts et Métiers ParisTech13, Royal Institute of Technology14, University of Siegen15, Katholieke Universiteit Leuven16, University of California, Berkeley17, Institution of Engineers, Sri Lanka18, Technical University of Berlin19, University of Glasgow20, King Abdulaziz University21
TL;DR: An organic scheme of the whole process of design, fabrication, experiments, models, models and image analyses of pantographic metamaterials is presented.
Abstract: In the last decade, the exotic properties of pantographic metamaterials have been investigated and different mathematical models (both discrete or continuous) have been introduced. In a previous publication, a large part of the already existing literature about pantographic metamaterials has been presented. In this paper, we give some details about the next generation of research in this field. We present an organic scheme of the whole process of design, fabrication, experiments, models and image analyses.
208 citations
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TL;DR: In this article, the authors focus on the design of wave-guides aimed to control wave propagation in micro-structured continua, with particular attention to piezoelectromechanical structures, having a strong coupling between macroscopic motion and some internal degrees of freedom.
199 citations
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TL;DR: In this paper, it was shown that the linearized homogenized model for a pantographic lattice must necessarily be a second gradient continuum, as defined in Germain (1973).
188 citations
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TL;DR: A comprehensive review of the main 3D printing methods, materials and their development in trending applications was carried out in this paper, where the revolutionary applications of AM in biomedical, aerospace, buildings and protective structures were discussed.
Abstract: Freedom of design, mass customisation, waste minimisation and the ability to manufacture complex structures, as well as fast prototyping, are the main benefits of additive manufacturing (AM) or 3D printing. A comprehensive review of the main 3D printing methods, materials and their development in trending applications was carried out. In particular, the revolutionary applications of AM in biomedical, aerospace, buildings and protective structures were discussed. The current state of materials development, including metal alloys, polymer composites, ceramics and concrete, was presented. In addition, this paper discussed the main processing challenges with void formation, anisotropic behaviour, the limitation of computer design and layer-by-layer appearance. Overall, this paper gives an overview of 3D printing, including a survey on its benefits and drawbacks as a benchmark for future research and development.
4,159 citations
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TL;DR: In this article, a clear classification of mechanical metamaterials have been established based on the fundamental material mechanics, which can be divided into strong-lightweight (E/ρ), pattern transformation with tunable stiffness, negative compressibility (−4G/3), and strong light-weight (S/ρ).
554 citations
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TL;DR: Gabrio Piola's scientific papers have been underestimated in mathematical physics literature as mentioned in this paper, but a careful reading of them proves that they are original, deep and far-reaching, and even even...
Abstract: Gabrio Piola’s scientific papers have been underestimated in mathematical physics literature. Indeed, a careful reading of them proves that they are original, deep and far-reaching. Actually, even ...
362 citations