The Experts below are selected from a list of 45978 Experts worldwide ranked by ideXlab platform
Tsu-wei Chou - One of the best experts on this subject based on the ideXlab platform.
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Modeling of elastic buckling of carbon nanotubes by molecular Structural Mechanics approach
Mechanics of Materials, 2004Co-Authors: Tsu-wei ChouAbstract:This paper reports the elastic buckling behavior of carbon nanotubes. Both axial compression and bending loading conditions are considered. The modeling work employs the molecular Structural Mechanics approach for individual nanotubes and considers van der Waals interaction in multi-walled nanotubes. The effects of nanotube diameter, aspect ratio, and tube chirality on the buckling force are investigated. Computational results indicate that the buckling force in axial compression is higher than that in bending, and the buckling forces for both compression and bending decrease with the increase in nanotube aspect ratio. The trends of variation of buckling forces with nanotube diameter are similar for single-walled and double-walled carbon nanotubes. Compared to a single-walled nanotube of the same inner diameter, the double-walled carbon nanotube shows a higher axial compressive buckling load, which mainly results from the increase of cross-sectional area, but no enhancement in bending load-bearing capacity. The buckling forces of nanotubes predicted by the continuum beam or column models are significantly different from those predicted by the atomistic model.
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a Structural Mechanics approach for the analysis of carbon nanotubes
International Journal of Solids and Structures, 2003Co-Authors: Chunyu Li, Tsu-wei ChouAbstract:Abstract This paper presents a Structural Mechanics approach to modeling the deformation of carbon nanotubes. Fundamental to the proposed concept is the notion that a carbon nanotube is a geometrical frame-like structure and the primary bonds between two nearest-neighboring atoms act like load-bearing beam members, whereas an individual atom acts as the joint of the related load-bearing beam members. By establishing a linkage between Structural Mechanics and molecular Mechanics, the sectional property parameters of these beam members are obtained. The accuracy and stability of the present method is verified by its application to graphite. Computations of the elastic deformation of single-walled carbon nanotubes reveal that the Young’s moduli of carbon nanotubes vary with the tube diameter and are affected by their helicity. With increasing tube diameter, the Young’s moduli of both armchair and zigzag carbon nanotubes increase monotonically and approach the Young’s modulus of graphite. These findings are in good agreement with the existing theoretical and experimental results.
Jingyu Shi - One of the best experts on this subject based on the ideXlab platform.
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Force-chain buckling in granular media: a Structural Mechanics perspective.
Philosophical Transactions of the Royal Society A: Mathematical Physical and Engineering Sciences, 2010Co-Authors: Giles W. Hunt, Antoinette Tordesillas, Steven C. Green, Jingyu ShiAbstract:Parallels are drawn between the response of a discrete strut on a linear elastic foundation and force-chain buckling in a constrained granular medium. Both systems buckle initially into periodic shapes, with wavelengths that depend on relative resistances to lateral displacement, and curvature in the buckled shape. Under increasing end shortening, the classical Structural model evolves to a localized form extending over a finite number of contributing links. By analogy, it is conjectured that the granular model of force-chain buckling might follow much the same evolutionary route into a shear band.
Manolis Papadrakakis - One of the best experts on this subject based on the ideXlab platform.
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the mosaic of high performance domain decomposition methods for Structural Mechanics formulation interrelation and numerical efficiency of primal and dual methods
Computer Methods in Applied Mechanics and Engineering, 2003Co-Authors: Yannis Fragakis, Manolis PapadrakakisAbstract:A multitude of domain decomposition methods (DDM) for Structural Mechanics is available in the literature today. A unified framework for formulating primal and dual DDM is thus presented in this paper, aiming at providing a mathematical platform for a uniform treatment of high performance DDM in Structural Mechanics. A novel approach for developing new DDM from existing methods is also proposed and is applied to dual and primal methods. In the field of the FETI methods, this approach leads to a new category of methods derived from existing FETI variants. Furthermore, two alternative formulations of the balancing domain decomposition method are described, while interrelations between the introduced and existing methods are established. Finally, comparative numerical tests demonstrate the differences in the computational performance of the methods in question.
Martin Haskett - One of the best experts on this subject based on the ideXlab platform.
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analysis of moment redistribution in fiber reinforced polymer plated rc beams
Journal of Composites for Construction, 2010Co-Authors: Martin Haskett, Deric John Oehlers, Mohamed R AliAbstract:Ductility of RC structures has always been a classical area of concrete research. Given the complexity of the problem, the great mass of research investigating ductility, and specifically, moment redistribution and rotational capacities, has used empirical approaches to quantify moment redistribution and invariably assumed that concrete crushing is the singular mode of failure. With the advent of new reinforcement materials such as fiber reinforced polymers, these empirical approaches are not necessarily appropriate as failure modes other than concrete crushing can occur. In this paper, the empirical approaches to moment redistribution are replaced by a Structural Mechanics approach that incorporates moment rotation directly into moment redistribution. A Structural Mechanics method for determining moment and rotation at failure for any RC section with any material properties is first presented and this is followed by a Structural Mechanics model for moment redistribution; these enable the moment redistribution capacities of any RC section to be quantified. Moment redistribution capacities of various sections are analyzed and it is shown that plated sections can have significant moment redistribution capacities much of which can be used in design.
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Design for Moment Redistribution in RC Beams Retrofitted with Steel Plates
Advances in Structural Engineering, 2010Co-Authors: Martin Haskett, Deric John Oehlers, M.s. Mohamed AliAbstract:It is now common practice to retrofit reinforced concrete members by adhesively bonding steel or fibre reinforced polymer plates to their surfaces. However, tests have shown that these plated RC structures tend to have less member ductility, or rotational capacity, than the unplated structure because of premature plate debonding. In this paper, Structural Mechanics approaches are described for both: quantifying the moment rotation capacity, or member ductility, of steel plated RC flexural members; and quantifying the moment redistribution capacity from the moment rotation capacity. It is shown how the moment redistribution Structural Mechanics model can be used to design for member ductility directly and, furthermore, it is applied to both externally bonded and near surface mounted steel plates. As would be expected, it is shown that steel plating produces more ductile members than fibre reinforced polymer plating.
Mohamed R Ali - One of the best experts on this subject based on the ideXlab platform.
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analysis of moment redistribution in fiber reinforced polymer plated rc beams
Journal of Composites for Construction, 2010Co-Authors: Martin Haskett, Deric John Oehlers, Mohamed R AliAbstract:Ductility of RC structures has always been a classical area of concrete research. Given the complexity of the problem, the great mass of research investigating ductility, and specifically, moment redistribution and rotational capacities, has used empirical approaches to quantify moment redistribution and invariably assumed that concrete crushing is the singular mode of failure. With the advent of new reinforcement materials such as fiber reinforced polymers, these empirical approaches are not necessarily appropriate as failure modes other than concrete crushing can occur. In this paper, the empirical approaches to moment redistribution are replaced by a Structural Mechanics approach that incorporates moment rotation directly into moment redistribution. A Structural Mechanics method for determining moment and rotation at failure for any RC section with any material properties is first presented and this is followed by a Structural Mechanics model for moment redistribution; these enable the moment redistribution capacities of any RC section to be quantified. Moment redistribution capacities of various sections are analyzed and it is shown that plated sections can have significant moment redistribution capacities much of which can be used in design.
