The Experts below are selected from a list of 113703 Experts worldwide ranked by ideXlab platform
I Calio - One of the best experts on this subject based on the ideXlab platform.
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closed form solution based genetic algorithm software application to multiple cracks detection on beam structures by Static Tests
Applied Soft Computing, 2018Co-Authors: A Greco, Alessandro Pluchino, F Cannizzaro, S Caddemi, I CalioAbstract:Abstract In this paper a procedure for the Static identification and reconstruction of concentrated damage distribution in beam-like structures, implemented in a dedicated software, is presented. The proposed damage identification strategy relies on the solution of an optimisation problem, by means of a genetic algorithm, which exploits the closed form solution based on the distribution theory of multi-cracked beams subjected to Static loads. Precisely, the adoption of the closed-form solution allows a straightforward evolution of an initial random population of chromosomes, representing different damage distributions along the beam axis, towards the fittest and selected as the sought solution. This method allows the identification of the position and intensity of an arbitrary number of cracks and is limited only by the amount of data experimentally measured. The proposed procedure, which has the great advantage of being robust and very fast, has been implemented in the powerful agent based software environment NetLogo, and is here presented and validated with reference to several benchmark cases of single and multi-cracked beams considering different load scenarios and boundary conditions. Sensitivity analyses to assess the influence of instrumental errors are also included in the study.
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closed form solution based genetic algorithm software application to multiple cracks detection on beam structures by Static Tests
arXiv: Computational Engineering Finance and Science, 2017Co-Authors: A Greco, Alessandro Pluchino, F Cannizzaro, S Caddemi, I CalioAbstract:In this paper a procedure for the Static identification and reconstruction of concentrated damage distribution in beam-like structures, implemented in a dedicated software, is presented. The proposed damage identification strategy relies on the solution of an optimisation problem, by means of a genetic algorithm, which exploits the closed form solution based on the distribution theory of multi-cracked beams subjected to Static loads. Precisely, the adoption of the latter closed-form solution allows a straightforward evolution of an initial random population of chromosomes, representing different damage distributions along the beam axis, towards the fittest and selected as the sought solution. This method allows the identification of the position and intensity of an arbitrary number of cracks and is limited only by the amount of data experimentally measured. The proposed procedure, which has the great advantage of being robust and very fast, has been implemented in the powerful agent based software environment NetLogo, and is here presented and validated with reference to several benchmark cases of single and multi-cracked beams considering different load scenarios and boundary conditions. Sensitivity analyses to assess the influence of instrumental errors are also included in the study.
A Greco - One of the best experts on this subject based on the ideXlab platform.
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closed form solution based genetic algorithm software application to multiple cracks detection on beam structures by Static Tests
Applied Soft Computing, 2018Co-Authors: A Greco, Alessandro Pluchino, F Cannizzaro, S Caddemi, I CalioAbstract:Abstract In this paper a procedure for the Static identification and reconstruction of concentrated damage distribution in beam-like structures, implemented in a dedicated software, is presented. The proposed damage identification strategy relies on the solution of an optimisation problem, by means of a genetic algorithm, which exploits the closed form solution based on the distribution theory of multi-cracked beams subjected to Static loads. Precisely, the adoption of the closed-form solution allows a straightforward evolution of an initial random population of chromosomes, representing different damage distributions along the beam axis, towards the fittest and selected as the sought solution. This method allows the identification of the position and intensity of an arbitrary number of cracks and is limited only by the amount of data experimentally measured. The proposed procedure, which has the great advantage of being robust and very fast, has been implemented in the powerful agent based software environment NetLogo, and is here presented and validated with reference to several benchmark cases of single and multi-cracked beams considering different load scenarios and boundary conditions. Sensitivity analyses to assess the influence of instrumental errors are also included in the study.
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closed form solution based genetic algorithm software application to multiple cracks detection on beam structures by Static Tests
arXiv: Computational Engineering Finance and Science, 2017Co-Authors: A Greco, Alessandro Pluchino, F Cannizzaro, S Caddemi, I CalioAbstract:In this paper a procedure for the Static identification and reconstruction of concentrated damage distribution in beam-like structures, implemented in a dedicated software, is presented. The proposed damage identification strategy relies on the solution of an optimisation problem, by means of a genetic algorithm, which exploits the closed form solution based on the distribution theory of multi-cracked beams subjected to Static loads. Precisely, the adoption of the latter closed-form solution allows a straightforward evolution of an initial random population of chromosomes, representing different damage distributions along the beam axis, towards the fittest and selected as the sought solution. This method allows the identification of the position and intensity of an arbitrary number of cracks and is limited only by the amount of data experimentally measured. The proposed procedure, which has the great advantage of being robust and very fast, has been implemented in the powerful agent based software environment NetLogo, and is here presented and validated with reference to several benchmark cases of single and multi-cracked beams considering different load scenarios and boundary conditions. Sensitivity analyses to assess the influence of instrumental errors are also included in the study.
Odd Sture Hopperstad - One of the best experts on this subject based on the ideXlab platform.
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low velocity impact behaviour and failure of stiffened steel plates
Marine Structures, 2017Co-Authors: Gaute Gruben, Odd Sture Hopperstad, S Solvernes, T Berstad, David Morin, Magnus LangsethAbstract:Abstract The behaviour and failure of stiffened steel plates subjected to transverse loading by an indenter is studied in this paper. Low-velocity dynamic and quasi-Static Tests of stiffened plates with geometry adopted from a typical external deck area on an offshore platform were conducted. The results show that the quasi-Static Tests provide a good reference for impact loading situations, although they displayed a larger displacement at fracture. Finite element simulations of the steel panel Tests were performed, using the elastic-viscoplastic J2 flow theory and a one-parameter fracture criterion. A relatively fine spatial discretization in the load application area was needed to capture accurately the onset of fracture. In order to locally refine the mesh, a method for automatic mesh refinement based on damage driven h-adaptivity was implemented and evaluated against results obtained with fixed meshes of various element sizes.
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low velocity impact on high strength steel sheets an experimental and numerical study
International Journal of Impact Engineering, 2016Co-Authors: Gaute Gruben, M Langseth, Egil Fagerholt, Odd Sture HopperstadAbstract:Abstract Low-velocity impact Tests were performed on dual-phase and martensitic steel sheets and compared with corresponding quasi-Static Tests. The geometry and loading condition of the specimens were similar to formability Tests, and the average strain rates before failure were in the range 80–210 s − 1 for the low-velocity Tests and 0.002-0.005 s − 1 for the quasi-Static Tests. For both loading rates, the sheets failed under pre-dominant membrane loading, and by varying the specimen geometry, the stress states prior to failure ranged from uniaxial tension to equi-biaxial tension. Thus, the most important stress states occurring during an impact event in a thin-walled structure are covered. The experiments were complemented by nonlinear finite element simulations, where higher-order solid elements and a refined mesh were applied to capture the failure of the sheets. The materials were modelled using the Hershey high-exponent yield function combined with the associated flow rule and isotropic hardening. Quasi-Static tensile and shear Tests and tensile Tests at elevated strain rates were performed to calibrate the constitutive relation. The results in terms of force-displacement curves and strain histories at critical positions in the specimens were similar for low-velocity and quasi-Static loading, independent of material and specimen geometry. This indicates that the quasi-Static test gives a good description of the sheet behaviour under low-velocity impact loading. The numerical simulations were found to be in good agreement with the experimental results, and strengthened the experimental finding that all the sheet-impact Tests, except the martensitic steel sheet in a state close to equi-biaxial tension, displayed local necking before final fracture.
Gaute Gruben - One of the best experts on this subject based on the ideXlab platform.
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low velocity impact behaviour and failure of stiffened steel plates
Marine Structures, 2017Co-Authors: Gaute Gruben, Odd Sture Hopperstad, S Solvernes, T Berstad, David Morin, Magnus LangsethAbstract:Abstract The behaviour and failure of stiffened steel plates subjected to transverse loading by an indenter is studied in this paper. Low-velocity dynamic and quasi-Static Tests of stiffened plates with geometry adopted from a typical external deck area on an offshore platform were conducted. The results show that the quasi-Static Tests provide a good reference for impact loading situations, although they displayed a larger displacement at fracture. Finite element simulations of the steel panel Tests were performed, using the elastic-viscoplastic J2 flow theory and a one-parameter fracture criterion. A relatively fine spatial discretization in the load application area was needed to capture accurately the onset of fracture. In order to locally refine the mesh, a method for automatic mesh refinement based on damage driven h-adaptivity was implemented and evaluated against results obtained with fixed meshes of various element sizes.
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low velocity impact on high strength steel sheets an experimental and numerical study
International Journal of Impact Engineering, 2016Co-Authors: Gaute Gruben, M Langseth, Egil Fagerholt, Odd Sture HopperstadAbstract:Abstract Low-velocity impact Tests were performed on dual-phase and martensitic steel sheets and compared with corresponding quasi-Static Tests. The geometry and loading condition of the specimens were similar to formability Tests, and the average strain rates before failure were in the range 80–210 s − 1 for the low-velocity Tests and 0.002-0.005 s − 1 for the quasi-Static Tests. For both loading rates, the sheets failed under pre-dominant membrane loading, and by varying the specimen geometry, the stress states prior to failure ranged from uniaxial tension to equi-biaxial tension. Thus, the most important stress states occurring during an impact event in a thin-walled structure are covered. The experiments were complemented by nonlinear finite element simulations, where higher-order solid elements and a refined mesh were applied to capture the failure of the sheets. The materials were modelled using the Hershey high-exponent yield function combined with the associated flow rule and isotropic hardening. Quasi-Static tensile and shear Tests and tensile Tests at elevated strain rates were performed to calibrate the constitutive relation. The results in terms of force-displacement curves and strain histories at critical positions in the specimens were similar for low-velocity and quasi-Static loading, independent of material and specimen geometry. This indicates that the quasi-Static test gives a good description of the sheet behaviour under low-velocity impact loading. The numerical simulations were found to be in good agreement with the experimental results, and strengthened the experimental finding that all the sheet-impact Tests, except the martensitic steel sheet in a state close to equi-biaxial tension, displayed local necking before final fracture.
Alessandro Pluchino - One of the best experts on this subject based on the ideXlab platform.
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closed form solution based genetic algorithm software application to multiple cracks detection on beam structures by Static Tests
Applied Soft Computing, 2018Co-Authors: A Greco, Alessandro Pluchino, F Cannizzaro, S Caddemi, I CalioAbstract:Abstract In this paper a procedure for the Static identification and reconstruction of concentrated damage distribution in beam-like structures, implemented in a dedicated software, is presented. The proposed damage identification strategy relies on the solution of an optimisation problem, by means of a genetic algorithm, which exploits the closed form solution based on the distribution theory of multi-cracked beams subjected to Static loads. Precisely, the adoption of the closed-form solution allows a straightforward evolution of an initial random population of chromosomes, representing different damage distributions along the beam axis, towards the fittest and selected as the sought solution. This method allows the identification of the position and intensity of an arbitrary number of cracks and is limited only by the amount of data experimentally measured. The proposed procedure, which has the great advantage of being robust and very fast, has been implemented in the powerful agent based software environment NetLogo, and is here presented and validated with reference to several benchmark cases of single and multi-cracked beams considering different load scenarios and boundary conditions. Sensitivity analyses to assess the influence of instrumental errors are also included in the study.
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closed form solution based genetic algorithm software application to multiple cracks detection on beam structures by Static Tests
arXiv: Computational Engineering Finance and Science, 2017Co-Authors: A Greco, Alessandro Pluchino, F Cannizzaro, S Caddemi, I CalioAbstract:In this paper a procedure for the Static identification and reconstruction of concentrated damage distribution in beam-like structures, implemented in a dedicated software, is presented. The proposed damage identification strategy relies on the solution of an optimisation problem, by means of a genetic algorithm, which exploits the closed form solution based on the distribution theory of multi-cracked beams subjected to Static loads. Precisely, the adoption of the latter closed-form solution allows a straightforward evolution of an initial random population of chromosomes, representing different damage distributions along the beam axis, towards the fittest and selected as the sought solution. This method allows the identification of the position and intensity of an arbitrary number of cracks and is limited only by the amount of data experimentally measured. The proposed procedure, which has the great advantage of being robust and very fast, has been implemented in the powerful agent based software environment NetLogo, and is here presented and validated with reference to several benchmark cases of single and multi-cracked beams considering different load scenarios and boundary conditions. Sensitivity analyses to assess the influence of instrumental errors are also included in the study.
