The Experts below are selected from a list of 111 Experts worldwide ranked by ideXlab platform
Stefano Bennati - One of the best experts on this subject based on the ideXlab platform.
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A simple and effective Nonlinear Elastic one-dimensional Model for the structural analysis of masonry arches
Meccanica, 2018Co-Authors: Riccardo Barsotti, Stefano BennatiAbstract:In this paper the static response of a masonry arch is studied by way of a one-dimensional Nonlinear Elastic Model in which masonry is regarded as a material with bounded tensile and compressive strengths. By following an approach analogous to that followed in the theory of bending of Elastic beams, the equilibrium problem for the arch leads to a free-boundary, Nonlinear differential problem. An approximate solution to such problem can be pursued by means of an ad hoc iterative procedure, illustrated in detail herein. The results obtained in three case studies are compared with some numerical and experimental results available in the literature. In addition, the case of an actual arch undergoing spreading of the springings is considered, and the distribution and possible evolution of the cracking pattern discussed.
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explicit solutions for depressed masonry arches loaded until collapse part i a one dimensional Nonlinear Elastic Model
Meccanica, 2017Co-Authors: Danila Aita, Riccardo Barsotti, Stefano BennatiAbstract:In this paper the equilibrium problem for masonry arches is formulated in terms of a suitable set of Nonlinear ordinary differential equations. We show that by making a small number of simple hypotheses it is possible to find the explicit expressions for the displacements and rotations of the cross-sections of an in-plane loaded masonry arch. To this end, the masonry arch is schematised as a curved, one-dimensional Nonlinear Elastic beam made of a material that is by hypothesis incapable of withstanding significant tensile stresses. In this first part of the two-part paper, the one-dimensional Model and the explicit expressions for the displacements and rotations, obtained by integrating the set of differential equations, are presented. In particular, the formal expressions for displacement, stress and strain fields are illustrated in full detail for an explicit, albeit approximate, solution for a statically determinate depressed arch subjected to a uniform vertical load.
Riccardo Barsotti - One of the best experts on this subject based on the ideXlab platform.
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A simple and effective Nonlinear Elastic one-dimensional Model for the structural analysis of masonry arches
Meccanica, 2018Co-Authors: Riccardo Barsotti, Stefano BennatiAbstract:In this paper the static response of a masonry arch is studied by way of a one-dimensional Nonlinear Elastic Model in which masonry is regarded as a material with bounded tensile and compressive strengths. By following an approach analogous to that followed in the theory of bending of Elastic beams, the equilibrium problem for the arch leads to a free-boundary, Nonlinear differential problem. An approximate solution to such problem can be pursued by means of an ad hoc iterative procedure, illustrated in detail herein. The results obtained in three case studies are compared with some numerical and experimental results available in the literature. In addition, the case of an actual arch undergoing spreading of the springings is considered, and the distribution and possible evolution of the cracking pattern discussed.
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explicit solutions for depressed masonry arches loaded until collapse part i a one dimensional Nonlinear Elastic Model
Meccanica, 2017Co-Authors: Danila Aita, Riccardo Barsotti, Stefano BennatiAbstract:In this paper the equilibrium problem for masonry arches is formulated in terms of a suitable set of Nonlinear ordinary differential equations. We show that by making a small number of simple hypotheses it is possible to find the explicit expressions for the displacements and rotations of the cross-sections of an in-plane loaded masonry arch. To this end, the masonry arch is schematised as a curved, one-dimensional Nonlinear Elastic beam made of a material that is by hypothesis incapable of withstanding significant tensile stresses. In this first part of the two-part paper, the one-dimensional Model and the explicit expressions for the displacements and rotations, obtained by integrating the set of differential equations, are presented. In particular, the formal expressions for displacement, stress and strain fields are illustrated in full detail for an explicit, albeit approximate, solution for a statically determinate depressed arch subjected to a uniform vertical load.
Michael J Ryan - One of the best experts on this subject based on the ideXlab platform.
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Nonlinear Elastic Model for flexible prediction of remotely sensed multitemporal images
IEEE Geoscience and Remote Sensing Letters, 2014Co-Authors: Md Al Mamun, Xiuping Jia, Michael J RyanAbstract:While an increasing number of satellite images are collected over a regular period in order to provide regular spatiotemporal information on land-use and land-cover changes, there are very few compression schemes in remotely sensed imagery that use historical data as a reference. Just as individual images can be compressed for separate transmission by taking into account their inherent spatial and spectral redundancies, the temporal redundancy between images of the same scene can also be exploited for sequential transmission. In this letter, we propose a Nonlinear Elastic method based on the general relationship to predict adaptively the current image from a previous reference image without any loss of information. The main feature of the developed method is to find the best prediction for each pixel brightness value individually using its own conditional probabilities to the previous image, instead of applying a single linear or Nonlinear Model. A codebook is generated to record the Nonlinear point-to-point relationship. This temporal lossless compression is incorporated with spatial- and spectral-domain predictions, and the performances are compared with those of the JPEG2000 standard. The experimental results show an improved performance by more than 5%.
Danila Aita - One of the best experts on this subject based on the ideXlab platform.
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explicit solutions for depressed masonry arches loaded until collapse part i a one dimensional Nonlinear Elastic Model
Meccanica, 2017Co-Authors: Danila Aita, Riccardo Barsotti, Stefano BennatiAbstract:In this paper the equilibrium problem for masonry arches is formulated in terms of a suitable set of Nonlinear ordinary differential equations. We show that by making a small number of simple hypotheses it is possible to find the explicit expressions for the displacements and rotations of the cross-sections of an in-plane loaded masonry arch. To this end, the masonry arch is schematised as a curved, one-dimensional Nonlinear Elastic beam made of a material that is by hypothesis incapable of withstanding significant tensile stresses. In this first part of the two-part paper, the one-dimensional Model and the explicit expressions for the displacements and rotations, obtained by integrating the set of differential equations, are presented. In particular, the formal expressions for displacement, stress and strain fields are illustrated in full detail for an explicit, albeit approximate, solution for a statically determinate depressed arch subjected to a uniform vertical load.
Robert Nick Bryan - One of the best experts on this subject based on the ideXlab platform.
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Nonlinear Elastic registration of brain images with tumor pathology using a biomechanical Model mri
IEEE Transactions on Medical Imaging, 1999Co-Authors: Stelios K Kyriacou, Christos Davatzikos, S J Zinreich, Robert Nick BryanAbstract:A biomechanical Model of the brain is presented, using a finite-element formulation. Emphasis is given to the Modeling of the soft-tissue deformations induced by the growth of tumors and its application to the registration of anatomical atlases, with images from patients presenting such pathologies. First, an estimate of the anatomy prior to the tumor growth is obtained through a simulated biomechanical contraction of the tumor region. Then a normal-to-normal atlas registration to this estimated pre-tumor anatomy is applied. Finally, the deformation from the tumor-growth Model is applied to the resultant registered atlas, producing an atlas that has been deformed to fully register to the patient images. The process of tumor growth is simulated in a Nonlinear optimization framework, which is driven by anatomical features such as boundaries of brain structures. The deformation of the surrounding tissue is estimated using a Nonlinear Elastic Model of soft tissue under the boundary conditions imposed by the skull, ventricles, and the falx and tentorium. A preliminary two-dimensional (2-D) implementation is presented in this paper, and tested on both simulated and patient data. One of the long-term goals of this work is to use anatomical brain atlases to estimate the locations of important brain structures in the brain and to use these estimates in pre-surgical and radiosurgical planning systems.
