Littérature scientifique sur le sujet « 3D-structural model »
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Articles de revues sur le sujet "3D-structural model"
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Lamarche, Juliette, et Magdalena Scheck-Wenderoth. « 3D structural model of the Polish Basin ». Tectonophysics 397, no 1-2 (mars 2005) : 73–91. http://dx.doi.org/10.1016/j.tecto.2004.10.013.
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Arndt, Dirk, Kristian Bär, Johann-Gerhard Fritsche, Ingo Sass et Andreas Hoppe. « 3D structural model of the Federal State of Hesse (Germany) for geopotential evaluation ». Zeitschrift der Deutschen Gesellschaft für Geowissenschaften 162, no 4 (1 décembre 2011) : 353–69. http://dx.doi.org/10.1127/1860-1804/2011/0162-0353.
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Cook, Douglas, Pradeep George et Margaret Julias. « 2D/3D hybrid structural model of vocal folds ». Journal of Biomechanics 45, no 2 (janvier 2012) : 269–74. http://dx.doi.org/10.1016/j.jbiomech.2011.10.030.
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Budko, Тatiana, et Lyudmila Lavrinenko2. « Structural Analysis and 3D Timber Spatial Structure Modeling ». Building constructions. Theory and Practice, no 8 (29 novembre 2021) : 4–16. http://dx.doi.org/10.32347/2522-4182.8.2021.4-16.
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The analysis of the structural form of the multi-volume dome structure using load-bearing wooden arches is performed. The complexity of the volumes and their connecting lines, as well as the requirement to conduct a non-linear analysis of long-span wooden elements at the request of Eurocode 5 make the information model necessary. It is noted that the design using this technology is developing in the direction of taking into account all stages of the structure life cycle. Information modeling of wooden structures in the world is the most prepared for the use of BIM-technologies. This is due to the sophisticated digital technologies for the production of modern wooden structures elements. An information model was formed for designing according to the regulations of Ukraine. The Information Model was created in the SAPFIR software package for further possibility of importing the model into the LIRA-CAD software package. The necessary auxiliary steps were used to build the model. The loads on the curved surface were calculated in the PC Espri. For further development of the nodes, 3D-modeling was used with the transfer of the information model into the PC Tekla Structures as a specialized environment for the constructive section of the project.
The presented analysis of the complex dome structure using wooden arches summarizes the approaches to the development of unique forms of structures using wood. The use of information models has significantly increased the complexity of architectural design and structural model taking into account the nonlinear effects of wood. The possibility of integrating these tools for further implementation in BIM-technology is shown.
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Román-González, Sergio A., Edson Edinho Robles-Gómez, Jorge Reyes, Johanna Bernáldez, Fernando Cortés-Guzmán, Karina Martínez-Mayorga, Fernando Lazcano-Pérez, Alexei Licea et Roberto Arreguín-Espinosa. « A 3D structural model of RsXXVIA, an ω-conotoxin ». Structural Chemistry 28, no 4 (22 novembre 2016) : 901–9. http://dx.doi.org/10.1007/s11224-016-0877-8.
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Sarlikioti, V., L. F. M. Marcelis et P. H. B. de Visser. « TOWARDS A 3D STRUCTURAL TOMATO MODEL FOR CALCULATING LIGHT INTERCEPTION ». Acta Horticulturae, no 893 (avril 2011) : 721–28. http://dx.doi.org/10.17660/actahortic.2011.893.77.
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Miki, Tomohiro, et Junichiro Niwa. « Nonlinear Analysis of RC Structural Members Using 3D Lattice Model ». Journal of Advanced Concrete Technology 2, no 3 (2004) : 343–58. http://dx.doi.org/10.3151/jact.2.343.
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Pepe, Massimiliano, Domenica Costantino et Alfredo Restuccia Garofalo. « An Efficient Pipeline to Obtain 3D Model for HBIM and Structural Analysis Purposes from 3D Point Clouds ». Applied Sciences 10, no 4 (12 février 2020) : 1235. http://dx.doi.org/10.3390/app10041235.
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The aim of this work is to identify an efficient pipeline in order to build HBIM (heritage building information modelling) and create digital models to be used in structural analysis. To build accurate 3D models it is first necessary to perform a geomatics survey. This means performing a survey with active or passive sensors and, subsequently, accomplishing adequate post-processing of the data. In this way, it is possible to obtain a 3D point cloud of the structure under investigation. The next step, known as “scan-to-BIM (building information modelling)”, has led to the creation of an appropriate methodology that involved the use of Rhinoceros software and a few tools developed within this environment. Once the 3D model is obtained, the last step is the implementation of the structure in FEM (finite element method) and/or in HBIM software. In this paper, two case studies involving structures belonging to the cultural heritage (CH) environment are analysed: a historical church and a masonry bridge. In particular, for both case studies, the different phases were described involving the construction of the point cloud and, subsequently, the construction of a 3D model. This model is suitable both for structural analysis and for the parameterization of rheological and geometric information of each single element of the structure.
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Wu, Xinming. « Building 3D subsurface models conforming to seismic structural and stratigraphic features ». GEOPHYSICS 82, no 3 (1 mai 2017) : IM21—IM30. http://dx.doi.org/10.1190/geo2016-0255.1.
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Subsurface modeling from seismic and borehole data is important for reservoir prediction, geophysical exploration, and production. A reasonable model should honor borehole rock properties and conform to seismic structural and stratigraphic features. Such a subsurface model can be difficult to build in cases complicated by faults and unconformities. Automatic and semiautomatic methods have been proposed to build subsurface models from seismic and borehole data; however, seismic structural and stratigraphic features and borehole measurements are not fully used in most methods. I have developed a workflow to fully use seismic and borehole data to build subsurface models that honor borehole measurements and conform to seismic horizons, faults, unconformities, and stratigraphic features such as channels. In this workflow, I first automatically remove the faulting and folding in seismic and borehole data and map them into an unfaulted and flattened space, in which seismic reflectors and borehole measurements corresponding to the same geologic layers are horizontally aligned. I then build a subsurface model in this unfaulted and flattened space by computing a sequence of 2D horizontal interpolations of borehole data. Each horizontal interpolation is guided by the stratigraphic features apparent in the corresponding horizontal seismic slice, so that the interpolant conforms to the seismic stratigraphic features. I finally map the interpolated model back into the input space and obtain a subsurface model that honors the seismic and borehole data. I demonstrate the proposed workflow using synthetic and real examples complicated by faults and unconformities.
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Parkinson, Ian H., Danielle Forbes, Peter Sutton-Smith et Nicola L. Fazzalari. « Model-Independent 3D Descriptors of Vertebral Cancellous Bone Architecture ». Journal of Osteoporosis 2010 (2010) : 1–6. http://dx.doi.org/10.4061/2010/641578.
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High-resolution micro computed tomography has enabled measurement of bone architecture derived from 3D representations of cancellous bone. Twenty-eight vertebral bodies were obtained from four embalmed male cadavers. From 3D anaglyphs, trabecular rod thickness and length were measured and the trabecular rod Buckling index was calculated. From 3D voxel-based datasets, bone volume density, trabecular thickness, and trabecular separation were measured. Also, trabecular bone pattern factor, structural model index, connectivity density, and degree of anisotropy were calculated. Bone volume density alone explains 59% of the variability in trabecular rod Buckling index. The addition of connectivity density, trabecular separation, and structural model index, in a multiple regression statistical model, improves the explanatory power to 77%. The relationships between measures of cancellous bone architecture and a derived measure of trabecular rod strength were investigated. Morphological descriptors of cancellous bone provide a composite explanatory model of trabecular rod strength.
Thèses sur le sujet "3D-structural model"
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Turrini, Claudio. « 3D structural model of the Po Valley basin, Northern Italy ». Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066464.
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Cette thèse présente le modèle 3D du bassin de la Plaine du Pô en Italie du nord. Les six parties de la thèse conduisent le lecteur à partir du cadre géologique de base aux géométries et à la cinématique de la déformation à travers la région, ainsi qu’aux possibles applications en milieu académique ou industriel. Le modèle a intégré des données éparses et de qualité inégale, tirées exclusivement de la littérature publique. L'ensemble de données utilisées pour la création du modèle se base strictement sur des données en profondeur (i.e. dans leur dimension de profondeur). Les données sismiques disponibles ont été intentionnellement écartées pour les raisons suivantes: a) elles sont mal distribuées à travers le secteur d'étude, b) elles se rapportent à des images de basse qualité, d) leur intégration dans le modèle aurait impliqué un long et difficile travail d’évaluation du meilleur modèle de vitesse de propagation des ondes sismiques dans les sédiments, le mieux à même d’être employé pour une conversion finale temps-profondeur, la variation latérale et verticale des vitesses sismiques à l’échelle régionale étant douteuse ou, au mieux, incertaine. La méthodologie appliquée, la création de modèles et l'analyse des améliorations du modèle 3D fournissent un certain nombre de conclusions sur la géométrie, le style structural et la cinématique de la Plaine du Pô et leur contribution en terme de sismicité du bassin et de son potentiel pétrolier, avec une confirmation mutuelle des, mais aussi par, les résultats locaux et épars obtenus par d’autres auteurs. Le résultat principal du projet est d'avoir prouvé la capacité du modèle à visualiser et analyser la complexité du bassin de la Plaine du Pô dans les 3 dimensions à différentes échelles d'observation, de l’échelle crustal jusqu'au niveau des prospectsThis thesis deals with the 3D model building of the Po Valley foreland basin in northern Italy. The six parts of the thesis lead from the basic geological framework to the deformation geometries and kinematics across the region, to some of the possible model applications, for both academia and industry. The model has integrated sparse and variable quality data, exclusively taken from the public literature. The complete dataset used for the performed model building, strictly relies on depth-data (i.e. in their depth dimension). As such, the few available seismic data have been intentionally left apart because: a) they are poorly distributed across the study-area, b) they definitely refer to low quality images, d) their integration into the model would have implied a long and difficult work about the definition of the most-likely sediment velocities to be used for an ultimate time-depth conversion, uncertain and, at best, questionable. The applied methodology, the related model building and the progressing analysis of 3D model results suggest and discuss a number of conclusions about the Po Valley structural geometries-style-kinematics. From such results can be derived implications on basin seismicity and hydrocarbon potential, while confirming (thus being supported by) the local and sparse results of previous authors. The major result from the project is to have proven the model capability in rendering and analyzing the entire Po Valley basin structural complexity in 3D dimensions, from crustal to field scale. Thanks to this, the model is unique in the literature of the region
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Costa, i. Torres Meritxell. « The first 3D structural model of an eukaryotic heteromeric aminoacid transporter / Primer model estructural en 3D d’ un transportador heteromèric d’aminoàcids eucariota ». Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/81916.
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Introduction
Heteromeric amino acid transporters (HATs) are composed of a heavy subunit (rBAT or 4F2hc) and a light subunit (b0 + AT, ASC1, LAT1, LAT2, y + LAT1, y + LAT2 and xCT), joined by a disulfide bridge (Chillaron et al. 2001). rBAT and 4F2hc are type II membrane glycoproteins (N-terminal cytoplasmic). Both have a single transmembrane segment, an N-terminal intracellular tail and an extracellular domain (ectodomain). As far as we know, the role of the heavy subunit is facilitating the transit of the light subunit to the plasma membrane. The light subunits are polytopic proteins unglycosylated, with 12 transmembrane segments, and the N-and C-terminal intracellular. The light subunit is the catalytically active subunit which confers specificity to the heterodimer on the transport system (Reig et al. 2002): LAT1 and LAT2 for system L , y+LAT1 and y+LAT2 for system y + L, asc for system ASC1; xCT for system Xc -, and b0+at for system b0, + (Chillaron et al. 2001).
Results
Overexpression of these human proteins was carried out with the methylotrophic yeast Pichia pastoris (strain KM71H) as expression system (based on Long et al. 2005). The main objective was to generate enough protein in a high level of purity to study the structure and check their function by transport assays. The different subunits, light and heavy, were cloned into the expression vector pPICZ (Invitrogen). To facilitate the purification of the different proteins, a cluster of 10 histidines was introduced by PCR at the N-terminus of the heavy subunits and a StrepTagII (IBA) at the N-terminus of the light subunits. 4F2hc is a glycoprotein with 4 possible targets for glycosylation. The glycosylations confer heterogeneity to protein, thus glycosylation targets were eliminated by directed mutagenesis. From all these human heavy and light subunits and heterodimers, only 4F2hc for the heavy subunits, LAT2 for the light subunits, and the heterodimer 4F2hc/LAT2 were overexpressed and extracted from the yeast membrane in enough amounts to continue with the purification step. The light subunit LAT2 was successfully purified but when the stability was analysed by size exclusion chromatography showed a clear profile of aggregation, concluding further studies. In contrast, the heavy subunit 4F2hc was stable after the exclusion chromatography for two days. The heterodimer 4F2hc/LAT2 proved to be stable after gel filtration analysis during one day. Thus, the heterodimer was significantly more stable than the light subunit alone, which allowed us to make an important statement. The catalytic subunit LAT2 needed their heavy subunit (i.e. 4F2hc) to increase the stability. This statement contrasted with the results for the heterodimer rBAT/b0+AT, in which was the heavy subunit rBAT the one who needed its light subunit b0+AT to a correct folding during its biogenesis (Bartoccioni et al. 2008; Rius et al. 2011).
Functional studies with human heterodimer 4F2hc/LAT2 were set up to check the role of 4F2hc in the transport. Firstly the functionality of the heterodimer 4F2hc/LAT2 and the light subunit LAT2 in the living cell was checked successfully, meaning a correct folding at expression level. The apparent KM in both cases was the same, remaining unanswered the role of the heavy subunit 4F2hc in the transport function. Next, reconstitution in liposomes was carried out successfully for 4F2hc/LAT2 but not for LAT2, due to the high aggregation tendency. 4F2hc/LAT2 showed the typical overshoot for an amino acid transporter.
To carry out the structural studies and due to the difficulty to maintain a stable soluble heterodimer, it was decided to carry out the technique of Single particle -negative staining (SP-NS) in the laboratory of Prof. Fotiadis in the University of Bern (Switzerland). The 3D model technique based on transmission electron microscopy (TEM) is relatively new and has been imposed for mammalian membrane proteins, allowing structural analysis with relatively small concentration of protein. The pure heterodimer was stained in a grid with uranyl formate at 0.75% (two drops optimized for 1 second, washing with water twice). This sample was analysed by transmission electron microscopy (TEM). Different images of projections in different orientations for 4F2hc/LAT2 were kept in a library of 11,000 picks. The refinement of the whole library allowed the 3D reconstruction of this protein by Mr. Meury. The model showed two asymmetric particles, one smaller, in which the crystal of the human ectodomain 4F2hc (Fort et al. 2007) fitted pretty well, and other bigger, which showed a black hole. Thus, the smaller particle was recognized as the heavy subunit, located on top of the light subunit. The resolution was 19 amstrongs, which was in the normal range for this method (from 16 amstrongs to 25 amstrongs).
Discussion
It was observed that the heavy subunit was located on top of the light subunit LAT2, and not in contact with the cell membrane as was firstly though. The size for the heavy subunit coincided with the existing 3D crystals of the human ectodomain which can fit quite accurately, always assuming the presence of the transmembrane segment in the 3D model. By contrast, the light subunit did not fit with the crystal structure of the prokaryotic homolog AdiC in the APA family (APC superfamily) (Gao et al. 2009) (Kowalczyk et al. 2011) due to the large amount of detergent surrounding this highly hydrophobic subunit in SP-NS method. In spite of that, when the size was compared with AdiC and Stet (a prokaryotic homolog in the LAT family with 30% of homology) studied in the same SP-NS method (Casagrande et al. 2009) the light subunit LAT2 coincided in size with its homologs, demonstrating that the increased volume was due to the detergent effect. Supporting the 4F2hc/LAT2 model, interaction studies with integrins (Feral et al 2005; Feral et al. 2007) and other membrane proteins involved in cell growth (ICAMI; Liu et al. 2003) and / or overexpressed in tumours (CD147/MCT1; Xu et al. 2005) suggest an effect in the transport function through the heavy subunit 4F2hc, which may be explained with an orientation on top of the light subunit and interaction by the external loops.
New Evidences: Recently, the 4F2hc/LAT2 heterodimer model in which the heavy subunit is located on top of the light subunit has been corroborated by cross-linking experiments by Miss Helena Alvarez in our laboratory. This fact, allow us to imagine how interactions between both subunits will carry out also when the disulphide bridge is missing. Analyzing the external loops in AdiC atomic structure (the closest paradigm with LATs at present) is found that the external loop 3 and the external loop 4 are the longest (around 25 residues). These loops are even longer in LAT2, which make possible the interaction between both subunits being the separation of 16 amstrongs in the 3D model. Both loops have important roles in the transport cycle based in LeuT fold. The external loop 3 has an important movement in the transition from outward-open conformation to occluded-outward conformation due to the tilt of 40o of the transmembrane 6. The external loop 4, moves down to lid the substrate pathway during the transition from occluded-outward conformation to the occluded-inward conformation.
Our new 3D model of a human heteromeric aminoacid transporter offers the opportunity to study new aspects about the role of the heavy subunit in the holotransporter. If the external loops join 4F2hc and LAT2 modulating the transport function in presence of other transmembrane proteins, or if 4F2hc only acts as a bollard of a multiproteic complex, rest to be studied in the future.Els transportadors heteromèrics d'aminoàcids (HATS) de metazous estan formats per una subunitat pesada (4F2hc o rBAT) (N-glicoproteïna amb 1 segment transmembrana i un gran ectodomini en el seu extrem C-terminal), i una subunitat lleugera (d'entre 10) unides covalentment per un pont disulfur, fent aquests transportadors únics entre els metazous. En humans, 6 subunitats lleugeres es troben formant heterodímers amb 4F2hc (LAT1, LAT2, y+ LAT1, y + LAT2, XCT i asc1) i una (b0, + AT) amb rBAT. Els HATs tenen incidència en la salut, ja que mutacions en qualsevol de les subunitats ocasionen aminoacidúries (cistinúria, lisinúria amb intolerància a proteïnes), són receptors virals o estan sobre expressats en cèl • lules tumorals. El nostre grup va determinar l'estructura de l'ectodomini de 4F2hc a 2.1 Å (Fort J et al. 2007), i recentment ha resolt l'estructura d'un homòleg procariota (AdiC d' E. coli, amb ~17% d´homologia) de les subunitats lleugeres a 3.0 Å de resolució (Kowalczyk et al. 2011). Per contra no hi ha informació estructural sobre els holo-transportadors HAT. El present treball ens mostra el primer model estructural a 19 Å d'un transportador HAT humà, el transportador 4F2hc/LAT2. La importància de 4F2hc, a part de tenir un paper important en immunologia, es troba en la seva sobreexpressió en cèl•lules tumorals, el que la converteix en una important diana per a tractaments i desenvolupament de vacunes contra el càncer. El model ens mostra com en aquest transportador, l´ectodomini de 4F2hc està situat sobre LAT2, suggerint interacció amb els bucles extracel•lulars del transportador i nos sols interacció a través del pont disulfur del segment transmembrana com es pensava anteriorment. Aquesta nova topologia explica la necessitat i la importància de que l'ectodomini de 4F2hc formi part de l´heterodímer 4F2hc/LAT2 i presenta un escenari estructural per al paper "chaperone-like" de 4F2hc sobre les subunitats lleugeres.
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Álvarez, Marimón Mª Elena. « Structural studies of Heteromeric Amino acid Transporters (HATs) : Validation of the first 3D structural model of a HAT (human 4F2hc/LAT2) and identification of new HAT targets for 3D‐crystallization ». Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/284082.
Texte intégralRésumé :
Heteromeric amino acid transporters (HATs) mediate the transport of amino acids through the plasma membrane. They are composed of two subunits (a heavy and a light one) linked by a conserved disulfide bridge. Genetic defects in the genes coding these HATs may affect its functionality or expression, leading to inherited aminoacidurias. Thus, solving the structure of the Eukaryotic HATs has become of great importance. However structural information about interactions between the heavy and light subunits of HATs is scarce.
In this work, human 4F2hc/L-type amino acid transporter 2 (LAT2) first low resolution 3D model obtained by single particle negative-staining transmission electron microscopy (TEM) was validated. In order to assess the interaction between both subunits of the heterodimer, crosslinking experiments between cysteine residues in both moieties was tried. Namely, two chemical spacers of different length (10.5 and 14.3 Å) were tested and crosslinking was observed for those mutants with pairing positions between 8 and 17.5 Å. Indeed, specific residues that crosslinked 4F2hc and LAT2 nearly completely (>80%). As a result of the positive results (as compared to the appropriate controls) the idea that 4F2hc-ED almost completely covers the extracellular surface of the transporter subunit LAT2 is reasonable. Moreover, further varied evidences (TEM, SPA and docking experiments) were in line with the obtained results, revealing that the extracellular domain of 4F2hc interacts with LAT2, almost completely covering the extracellular face of the transporter. The interaction of 4F2hc with LAT2 gives insights into the structural bases for light subunit recognition and the stabilizing role of the ancillary protein in HATs. In addition, it has been demonstrated that the ectodomain of 4F2hc suffices the stabilization of the light subunit.
The second goal of the thesis was to find a suitable HAT candidate to perform crystallization trials and posterior structure elucidation, since human 4F2h/LAT2 was not stable enough for this aim. Until now, only the human 4F2hc ectodomain atomic structure has been solved (Fort et al., 2007), and some low sequence amino acid identity prokaryotic homologues of LATs.
In order to identify putative good eukaryotic light subunits for 3D crystallization the adopted GFP‐based Saccharomyces cerevisiae protocol for our transporters resulted successful since it allowed to find three putative good candidate eukaryotic light subunits for 3D crystallization studies. GFP technology allowed quick expression screening, membrane protein-detergent solubilization screening and finally another screening step including assessment of the stability by ultracentrifugation dispersity sedimentation.
Once the candidates selected in the best conditions, further purification was required (size exclusion chromatography) before attempting crystallization. In this sense, further efforts were delivered in order to try to enhance the stability (and minimize aggregation). Thus, addition of lipids in the solubilization step and during protein purification was used to mimic the protein membrane environment and reduce the aggregation. Really interesting is the stabilizing effect that cholesterol has on almost all light subunits tested. This is in concordance with the fact that 4F2hc has been found located in lipid rafts where membrane are rich in cholesterol. Removal of reactive cysteine and generation of truncated versions of the protein in the C and N terminal were introduced to increase the crystallization probability. This work ended with the finding of 3 good candidates for crystallization screenings, and the best candidate was optimized in terms of stability and protein flexibility for crystallization studies. Just preliminary crystallization trials were done.Los transportadores heteroméricos de aminoácidos (HAT) median el transporte de aminoácidos a través de la membrana plasmática. Representan el único ejemplo de transportadores de solutos formado por dos subunidades distintas unidas por un puente disulfuro. Debido a su gran relevancia en fisiología (asociados a aminoacidurias, infección por virus, cáncer,…) el estudio de su estructura-función resulta clave. Debido a su naturaleza, son proteínas difíciles de cristalizar, de las que sólo se conoce la estructura atómica del ectodominio de 4F2hc humano. En este escenario la tesis se centró en la validación del primer modelo 3D a baja resolución de un HAT humano (4F2hc/LAT2), mediante experimentos de crosslinking entre subunidades, e identificación de nuevos candidatos para cristalización 3D. Para ello se seleccionaron 24 subunidades ligeras de distintas especies eucariotas y se testaron en un proceso de selección para determinar el/los mejores candidatos. El primer objetivo de la tesis concluyó con la determinación de residuos concretos en 4F2hc y LAT2 cercanos a una distancia de 3-14 Å mediante la utilización de crosslinkings de cisteínas. Finalmente, tres líneas distintas: el modelo 3D obtenido por microscopía electrónica de transmisión y tinción negativa de partículas individuales (en colaboración con Dr. Fotiadis), los experimentos de crosslinking, y el docking generado en colaboración con Dr. Fdz-Recio, demostraron que 4F2hc-ED cubre, casi completamente, la superficie extracelular de LAT2. Además, se demostró que el ectodominio de 4F2hc es suficiente para estabilizar LAT2. Como resultados del segundo objetivo, tres subunidades ligeras fueron seleccionadas, tras adaptar el protocolo desarrollado por Drew et al.,2008, como mejores candidatas para estudios de cristalización 3D. Posteriormente, distintas estrategias se siguieron para mejorar la estabilidad de la mejor candidata: eliminación de la cisteína reactiva, adición de lípidos a la muestra, cambio de sistema de expresión para aumentar su expresión a células de insecto Sf9. Además, se generaron mutantes delecionados en N y C terminal para reducir su flexibilidad y aumentar la probabilidad de cristalización. Se concluyó en encontrar un buen candidato para estudios de cristalización.
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Rumpler, Romain. « Efficient finite element approach for structural-acoustic applicationns including 3D modelling of sound absorbing porous materials ». Phd thesis, Conservatoire national des arts et metiers - CNAM, 2012. http://tel.archives-ouvertes.fr/tel-00726915.
Texte intégralRésumé :
In the context of interior noise reduction, the present work aims at proposing Finite Element (FE) solution strategies for interior structural-acoustic applications including 3D modelling of homogeneous and isotropic poroelastic materials, under timeharmonic excitations, and in the low frequency range. A model based on the Biot-Allard theory is used for the poroelastic materials, which is known to be very costly in terms of computational resources. Reduced models offer the possibility to enhance the resolution of such complex problems. However, their applicability to porous materials remained to be demonstrated.First, this thesis presents FE resolutions of poro-elasto-acoustic coupled problems using modal-based approaches both for the acoustic and porous domains. The original modal approach proposed for porous media, together with a dedicated mode selection and truncation procedure, are validated on 1D to 3D applications.In a second part, modal-reduced models are combined with a Padé approximants reconstruction scheme in order to further improve the efficiency.A concluding chapter presents a comparison and a combination of the proposed methods on a 3D academic application, showing promising performances. Conclusions are then drawn to provide indications for future research and tests to be conducted in order to further enhance the methodologies proposed in this thesis.
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Rumpler, Romain. « Efficient Finite Element Approach for Structural-Acoustic Applications including 3D modelling of Sound Absorbing Porous Materials ». Doctoral thesis, KTH, MWL Numerisk akustik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-90335.
Texte intégralRésumé :
In the context of interior noise reduction, the present work aims at proposing Finite Element (FE) solution strategies for interior structural-acoustic applications including 3D modelling of homogeneous and isotropic poroelastic materials, under timeharmonic excitations, and in the low frequency range. A model based on the Biot-Allard theory is used for the poroelastic materials, which is known to be very costly in terms of computational resources. Reduced models offer the possibility to enhance the resolution of such complex problems. However, their applicability to porous materials remained to be demonstrated.First, this thesis presents FE resolutions of poro-elasto-acoustic coupled problems using modal-based approaches both for the acoustic and porous domains. The original modal approach proposed for porous media, together with a dedicated mode selection and truncation procedure, are validated on 1D to 3D applications.In a second part, modal-reduced models are combined with a Padé approximants reconstruction scheme in order to further improve the efficiency.A concluding chapter presents a comparison and a combination of the proposed methods on a 3D academic application, showing promising performances. Conclusions are then drawn to provide indications for future research and tests to be conducted in order to further enhance the methodologies proposed in this thesis.Dans le contexte de lutte contre les nuisances sonores, cette thèse porte sur le développement de méthodes de résolution efficaces par éléments finis, pour des problèmes de vibroacoustique interne avec interfaces dissipatives, dans le domaine des basses fréquences. L’étude se limite à l’utilisation de solutions passives telles que l’intégration de matériaux poreux homogènes et isotropes, modélisés par une approche fondée sur la théorie de Biot-Allard. Ces modèles étant coûteux en terme de résolution, un des objectifs de cette thèse est de proposer une approche modale pour la réduction du problème poroélastique, bien que l’adéquation d’une telle approche avec le comportement dynamique des matériaux poreux soit à démontrer.Dans un premier temps, la résolution de problèmes couplés élasto-poro-acoustiques par sous-structuration dynamique des domaines acoustiques et poreux est établie. L’approche modale originale proposée pour les milieux poroélastiques, ainsi qu’une procédure de sélection des modes significatifs, sont validées sur des exemples 1D à 3D.Une deuxième partie présente une méthode combinant l’utilisation des modèles réduits précédemment établis avec une procédure d’approximation de solution par approximants de Padé. Il est montré qu’une telle combinaison offre la possibilité d’accroître les performances de la résolution (allocation mémoire et ressources en temps de calcul).Un chapitre dédié aux applications permet d’évaluer et comparer les approches sur un problème académique 3D, mettant en valeur leurs performances encourageantes. Afin d’améliorer les méthodes établies dans cette thèse, des perspectives à ces travaux de recherche sont apportées en conclusion.
QC 20120224
FP6 Marie-Curie Smart Structures
FP7 Marie-Curie Mid-Frequency
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Vidal, Royo Oskar. « 3D Reconstruction and Modelling of the Sierras Exteriores Aragonesas (Southern Pyrenees, Spain). Structural Evolution of the Pico del Águila anticline ». Doctoral thesis, Universitat de Barcelona, 2010. http://hdl.handle.net/10803/39077.
Texte intégralRésumé :
This Thesis reports on the integration of different modelling techniques to construct a unified and better constrained conceptual model of structural evolution of the Pico del Águila anticline (External Sierras, Southern Pyrenees, Spain). The structure is a well-known example of detachment fold, which exhibits a N-S structural trend, parallel to the direction of tectonic transport in the Southern Pyrenees. Based on field observations of an unevenly distributed Triassic décollement, analogue modelling show how to generate orogen-perpendicular structures which may result in transverse anticlines. Numerical models investigate the effect of a complex mechanical stratigraphy, characterized by an interlayering of competent and incompetent layers, plus syn-kinematic sedimentation in the fold growth. Based on field data and seismic interpretations, a 3D reconstruction and sequential geomechanical restoration of the Pico del Águila anticline reports the coexistence of multiple folding mechanisms occurring simultaneously in different units and structural domains of the fold, leading to a complex strain pattern that can not be assessed by simplistic kinematic 2D approaches. By integrating the presented models with the previous data in the region, we discuss about the benefits and drawbacks of each modelling technique and present an integrated model of structural evolution for the Pico del Águila anticline. This brings a better comprehension of the structure as well as the processes that drove the evolution of the N-S detachment anticlines in the External Sierras of the Southern Pyrenees.L’anticlinal del Pico del Águila és un conegut exemple de plec de desenganxament amb sedimentació marina a fluvio-deltaica associada, amb una tendència estructural N-S, paral•lela a la direcció de transport tectònic dels Pirineus Meridionals. Basat en observacions de camp que indiquen una distribució heterogènia del nivell de desenganxament Triàsic, els models analògics mostren el procés de generació d’estructures perpendiculars al sistema orogènic que poden donar lloc als anticlinals N-S descrits a les Sierras Exteriores Aragonesas. Els models numèrics investiguen l’efecte d’una estratigrafia mecànica complexa, caracteritzada per una intercalació d’unitats competents i incomptetents (amb marcades diferències en el grau de competència, per tant) i de la sedimentació sin-cinemàtica en el creixement i evolució de l’anticlinal. Basat en dades de camp i interpretacions de perfils sísmics s’ha portat a terme una reconstrucció i restitució geomecànica tridimensional de l’anticlinal del Pico del Águila. D’aquestes se’n deriva la coexistència de de múltiples mecanismes de plegament actuant simultàniament en diferents unitats i dominis estructurals, la qual implica al seu torn un patró i distribució de la deformació que no poden ser avaluats mitjançant aproximacions o tècniques de modelització cinemàtiques o/i bidimensionals. S’integren també els resultats obtinguts a partir de les esmentades tècniques de modelització amb les dades i coneixements previs de la regió, es discuteixen els beneficis, desavantatges i limitacions de cadascuna d’aquestes tècniques de modelització, i es presenta un model integrat d’evolució estructural del Pico del Águila. Aquest anàlisi crític dels resultats i aquest esforç d’integració porten sense dubte cap a una millor comprensió de l’estructura i dels processos que menaren l’evolució dels plecs de desenganxament N-S de les Sierras Exteriores Aragonesas dels Pirineus Meridionals.
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Preuksakarn, Chakkrit. « Reconstructing plant architecture from 3D laser scanner data ». Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20116/document.
Texte intégralRésumé :
Les modèles virtuels de plantes sont visuellement de plus en plus réalistes dans les applications infographiques. Cependant, dans le contexte de la biologie et l'agronomie, l'acquisition de modèles précis de plantes réelles reste un problème majeur pour la construction de modèles quantitatifs du développement des plantes.Récemment, des scanners laser 3D permettent d'acquérir des images 3D avec pour chaque pixel une profondeur correspondant à la distance entre le scanner et la surface de l'objet visé. Cependant, une plante est généralement un ensemble important de petites surfaces sur lesquelles les méthodes classiques de reconstruction échouent. Dans cette thèse, nous présentons une méthode pour reconstruire des modèles virtuels de plantes à partir de scans laser. Mesurer des plantes avec un scanner laser produit des données avec différents niveaux de précision. Les scans sont généralement denses sur la surface des branches principales mais recouvrent avec peu de points les branches fines. Le cœur de notre méthode est de créer itérativement un squelette de la structure de la plante en fonction de la densité locale de points. Pour cela, une méthode localement adaptative a été développée qui combine une phase de contraction et un algorithme de suivi de points.Nous présentons également une procédure d'évaluation quantitative pour comparer nos reconstructions avec des structures reconstruites par des experts de plantes réelles. Pour cela, nous explorons d'abord l'utilisation d'une distance d'édition entre arborescence. Finalement, nous formalisons la comparaison sous forme d'un problème d'assignation pour trouver le meilleur appariement entre deux structures et quantifier leurs différencesIn the last decade, very realistic rendering of plant architectures have been produced in computer graphics applications. However, in the context of biology and agronomy, acquisition of accurate models of real plants is still a tedious task and a major bottleneck for the construction of quantitative models of plant development. Recently, 3D laser scanners made it possible to acquire 3D images on which each pixel has an associate depth corresponding to the distance between the scanner and the pinpointed surface of the object. Standard geometrical reconstructions fail on plants structures as they usually contain a complex set of discontinuous or branching surfaces distributed in space with varying orientations. In this thesis, we present a method for reconstructing virtual models of plants from laser scanning of real-world vegetation. Measuring plants with laser scanners produces data with different levels of precision. Points set are usually dense on the surface of the main branches, but only sparsely cover thin branches. The core of our method is to iteratively create the skeletal structure of the plant according to local density of point set. This is achieved thanks to a method that locally adapts to the levels of precision of the data by combining a contraction phase and a local point tracking algorithm. In addition, we present a quantitative evaluation procedure to compare our reconstructions against expertised structures of real plants. For this, we first explore the use of an edit distance between tree graphs. Alternatively, we formalize the comparison as an assignment problem to find the best matching between the two structures and quantify their differences
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Cocchi, Luca <1978>. « Magnetic structural evidences of the 41(st) parallel zone (Tyrrhenian Sea) inferred from potential field data : the 3D model of the discontinuity ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/453/1/Tesi_Cocchi_XIX_ciclo.pdf.
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Cocchi, Luca <1978>. « Magnetic structural evidences of the 41(st) parallel zone (Tyrrhenian Sea) inferred from potential field data : the 3D model of the discontinuity ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/453/.
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Varun. « A Simplified Model for Lateral Response of Caisson Foundations ». Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14016.
Texte intégralRésumé :
Caisson or pier foundations are encountered as part of the foundation system of tall structures such as bridges, transmission towers, heliostats, etc, and correspond to rigid blocks of length-to-diameter (D/B) ratio on the order of D/B = 2-6. As a result of their geometry and stiffness characteristics, the mechanisms of load transfer from the superstructure to the surrounding soil and their kinematic response to seismic wave propagation are governed by a complex stress distribution at the pier-soil interface, which cannot be adequately represented by means of simplified Winkler models for shallow foundations or flexible piles. Continuum model solutions, such as 3D finite elements (FE) cannot be employed frequently in practice for the design of non-critical facilities due to the cost and effort associated with these analyses. The objective of this work is to develop a Winkler-type model for the analysis of transversely-loaded caissons, which approximately accounts for all the main soil resistance mechanisms mobilized, while retaining the advantages of simplified methodologies for design at intermediate levels of target accuracy. Investigation of the governing load-transfer mechanisms and development of complex spring functions is formulated on the basis of 3D FE simulations. Initially, the soil-structure stiffness matrix is computed by subjecting the pier to transverse static and dynamic loading at the top, and numerically estimating the response. Complex frequency-dependent functions are next developed for the spring constants by equating the stiffness matrix terms to the analytical expressions developed for the four-spring model. Sensitivity analyses are conducted for optimization of the truncated numerical domain size, finite element size and far-field dynamic boundary conditions to avoid spurious wave reflections. Simulations are next conducted to evaluate the transient response of the foundation subjected to vertically propagating shear waves, and results are compared to the response predicted by means of the 4-spring model. Finally, the applicability of the method is assessed for soil profiles with depth-varying properties. While the methodology developed is applicable for linear elastic media with no material damping, the expressions of complex spring functions may be extended to include hysteretic damping, nonlinear soil behavior and soil-foundation interface separation, as shown in the conclusions.
Livres sur le sujet "3D-structural model"
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Benschop, Yvonne, Charlotte Holgersson, Marieke van den Brink et Anna Wahl. Future Challenges for Practices of Diversity Management in Organizations. Sous la direction de Regine Bendl, Inge Bleijenbergh, Elina Henttonen et Albert J. Mills. Oxford University Press, 2016. http://dx.doi.org/10.1093/oxfordhb/9780199679805.013.24.
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In this chapter, we zoom in on a set of diversity practices that prevail in organizations: training, mentoring, and networks. These practices meet scholarly critique for their lack of transformation. They are often seen as targeting ‘the Other’ employees to get them at par with majority employees, leaving the current system intact. However, it can be questioned whether values, practices and routines indeed remain intact in the organizations that engage in diversity training, mentoring, and networks. The aim of this chapter is to come to a better assessment of the transformative potential of these popular diversity practices. The notion of transformative potential means the potential for diversity practices to diminish inequalities by changing organizational work practices, norms, routines and interactions. We use the so-called 3D model that provides a systematic way of assessing diversity practices. We find that training, mentoring and networking can denote so many different things that it is as incorrect to dismiss any single of these interventions, as it is to praise them in general. We conclude that a multi-dimensional power perspective challenging structural discrimination and addressing conflicting interests is key to any diversity practice that strives for transformative change.
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Cao, Gang, et Lance DeLong. Physics of Spin-Orbit-Coupled Oxides. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780199602025.001.0001.
Texte intégralRésumé :
Prior to 2010, most research on the physics and chemistry of transition metal oxides was dominated by compounds of the 3d-transition elements such as Cr, Mn, Fe, Co, Ni, and Cu. These materials exhibited novel, important phenomena that include giant magnetoresistance in manganites, as well as high-temperature superconductivity in doped La2CuO4 and related cuprates. The discovery in 1994 of an exotic superconducting state in Sr2RuO4 shifted some interest toward ruthenates. Moreover, the realization in 2008 that a novel variant of the classic Mott metal-insulator transition was at play in Sr2IrO4 provided the impetus for a burgeoning group of studies of the influence of strong spin-orbit interactions in “heavy” (4d- and 5d-) transition-element oxides. This book reviews recent experimental and theoretical evidence that the physical and structural properties of 4d- and 5d-oxides are decisively influenced by strong spin-orbit interactions that compete or collaborate with comparable Coulomb, magnetic exchange, and crystalline electric field interactions. The combined effect leads to unusual ground states and magnetic frustration that are unique to this class of materials. Novel couplings between the orbital/lattice and spin degrees of freedom, which lead to unusual types of magnetic order and other exotic phenomena, challenge current theoretical models. Of particular interest are recent investigations of iridates and ruthenates focusing on strong spin-orbit interactions that couple the lattice and spin degrees of freedom.
Chapitres de livres sur le sujet "3D-structural model"
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Jianxin, Xu, Zhou Jingtao, Li Jianfeng et Dong Siyang. « 3D-Model-Based Integrated Capp System for Aircraft Structural Parts ». Dans Advances in Intelligent and Soft Computing, 15–25. Berlin, Heidelberg : Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-10430-5_2.
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Zhu, Kewei, et Bing Li. « Research on the Integration Technology of Structural Performance Evaluation and 3D Design for Spatial Steel Structure Bridges ». Dans Advances in Frontier Research on Engineering Structures, 9–19. Singapore : Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-8657-4_2.
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AbstractWith the increase of steel structure bridges, the design of steel structure bridges begin to evolve in the direction of high quality, high precision, and short design period. In order to improve the design quality and efficiency of spatial steel structure bridges, the integration technology of structural performance evaluation and 3D design of spatial steel structure bridges is studied. Firstly, the 3D design is carried out based on the rapid design method, and then the finite element simulation is conducted by software to analyze its structural performance and optimize the 3D design model. The research results link the rapid design and structural analysis software systematically, so as to realize the integrated design of spatial irregular bridge components with BIM and FEM technology.
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Costantino, Domenica, Massimiliano Pepe, Marcello Carrieri et Alfredo Restuccia Garofalo. « A Procedure to Obtain a 3D Model in Bim and Structural Analysis Software ». Dans R3 in Geomatics : Research, Results and Review, 157–69. Cham : Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-62800-0_13.
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Fujisawa, Yasuo, et Nobuyoshi Yabuki. « Cooperative Information Sharing between a 3D Model and Structural Analysis Software for Railway Viaducts ». Dans Lecture Notes in Computer Science, 203–6. Berlin, Heidelberg : Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-32609-7_28.
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Becker, Thomas, Sven Weisbrich, Cheng-Chieh Wu et Frank Neitzel. « Advances in Structural Monitoring by an Integrated Analysis of Sensor Measurements and 3D Building Model ». Dans Lecture Notes in Geoinformation and Cartography, 141–56. Cham : Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-12181-9_9.
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Beltrán-Fernández, J. A., L. H. Hernández-Gómez, G. Urriolagoitia-Calderón, A. González-Rebatú, G. Urriolagoitia-Sosa, M. M. Galán Vera et E. Escalante-Rodríguez. « Assessment of the Structural Integrity of C3–C5 Cervical Porcine Vertebrae Model Based on 2D Classic CAD, 3D Scanner and 3D Computed Tomography ». Dans Analysis and Design of Biological Materials and Structures, 3–17. Berlin, Heidelberg : Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-22131-6_1.
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de Brevern, Alexandre G. « 3D Structural Models of Transmembrane Proteins ». Dans Methods in Molecular Biology, 387–401. Totowa, NJ : Humana Press, 2010. http://dx.doi.org/10.1007/978-1-60761-762-4_20.
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Rüd, Sophie, Hilmar Müller, Helmut Fleischer et Christoph Stephan. « Development of a Verification Procedure of Partial Loading on Existing Solid Hydraulic Structures - Probabilistic Assessment for 3D Material Variations ». Dans Lecture Notes in Civil Engineering, 372–83. Singapore : Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-6138-0_33.
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AbstractOne of the challenges in assessing the load-bearing capacity of existing solid hydraulic structures is the formal verification of concentrated loads for plain concrete. Due to the age bandwidth of such structures in Germany, this applies to hundreds of cases and especially to older structures of rammed concrete. Typical examples of components subjected to partial loads are found at weir pillars: e.g. support niches of inspection closures. Although they cannot be formally verified using the current regulations, the BAW Code of Practice “Evaluation of the load bearing capacity of existing solid hydraulic structures” (TbW) allows more detailed investigation methods to be applied, e.g. the use of non-linear probabilistic calculations. The principle research motivations are a higher loading capacity by numerical simulations with a more realistic material model compared to the usual linear calculations and a higher loading capacity by reproducing a “natural” bandwidth of material characteristics in these simulations. The aim of the current research project is the development and standardisation of the numerical simulations for such a verification procedure and its underlying safety concept by a classification of structural markers. As a result, the necessity of complex reinforcements for such structures could be assessed. The paper introduces the research concept and addresses the investigation steps regarding measured and generic 3D material distributions and FEM representation specifics as the material model. Furthermore, the preparation of the stochastic analysis is introduced by a demonstration model: The resulting hundreds to thousands of simulations of individual cases enable the stochastic analysis of metamodels to deduce general probabilistic results. Prospectively, the demonstration model will be transferred to further component measures and compressive strength classes.
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Condemine, Cyril, Loic Grau, Yves Masson et Sebastien Aubry. « Live Digital Twin for Hydraulic Structures Fatigue Estimation ». Dans Lecture Notes in Civil Engineering, 494–505. Singapore : Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-6138-0_43.
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AbstractMaintaining hydraulic structures such as dams, penstocks, or water lock gates in operating conditions and optimizing their maintenance costs are key issues for energy production or river navigation. The ultimate objective is to know the real state of fatigue and damage of the structure and identify any related anomalies. In this paper, we introduce a digital twin, for fatigue evaluation merging measured data obtained with an embedded sensor network and a 3D numerical model that converts in real time measured data into fatigue. After 3 years of R&D collaboration between CNR and Morphosense in the maintenance of navigation lock gates or dam gates, this presentation exposes how the proposed Live Digital Twin solution contributes to fatigue evaluation and more generally to global structural monitoring in dealing with fundamental issues of hydraulic structures: risk assessment, maintenance in operating conditions and maintenance costs optimization. After a context and state of the art introduction, the second part will detail the system overview. In the third part, the monitoring system will be addressed.
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Kulah, S., U. Aridogan et I. Basdogan. « Investigation of an Active Structural Acoustic Control System on a Complex 3D Structure ». Dans Topics in Modal Analysis, Volume 7, 715–21. New York, NY : Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-6585-0_68.
Texte intégralActes de conférences sur le sujet "3D-structural model"
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Li, Chengcheng, et Jinxian Qi. « Structural Analysis of 3D Printing Model ». Dans 2017 7th International Conference on Mechatronics, Computer and Education Informationization (MCEI 2017). Paris, France : Atlantis Press, 2017. http://dx.doi.org/10.2991/mcei-17.2017.63.
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Miorelli, Federico, Randall L. Mackie, Fabien Gilbert et Wolfgang Soyer. « Foothills structural model de-risking with 3D magnetotellurics ». Dans SEG Technical Program Expanded Abstracts 2019. Society of Exploration Geophysicists, 2019. http://dx.doi.org/10.1190/segam2019-3198037.1.
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Fanfani, Marco, et Carlo Colombo. « Structural Change Detection by Direct 3D Model Comparison ». Dans 14th International Conference on Computer Vision Theory and Applications. SCITEPRESS - Science and Technology Publications, 2019. http://dx.doi.org/10.5220/0007260607600767.
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Hu, Chunhua, Dong Yang, Pingping Li et Ting Yun. « 3D Dynamic Visualization of Single Poplar Combined Growth Model with Structural Model ». Dans 2016 International Conference on Intelligent Control and Computer Application (ICCA 2016). Paris, France : Atlantis Press, 2016. http://dx.doi.org/10.2991/icca-16.2016.20.
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Black, Jonathan, Lynnane George et Eric Swenson. « Measuring and Modeling 3D Mode Shapes of FalconSAT-5 Structural Engineering Model ». Dans 49th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference
16th AIAA/ASME/AHS Adaptive Structures Conference
10t. Reston, Virigina : American Institute of Aeronautics and Astronautics, 2008. http://dx.doi.org/10.2514/6.2008-1851.
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Bérard, T., J. Desroches, Y. Yang, X. Weng et K. Olson. « High-Resolution 3D Structural Geomechanics Modeling for Hydraulic Fracturing ». Dans SPE Hydraulic Fracturing Technology Conference. SPE, 2015. http://dx.doi.org/10.2118/spe-173362-ms.
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Abstract Three-dimensional (3D) geomechanical models built at reservoir scale lack resolution at the well sector scale (e.g., hydraulic fracture scale), at least laterally. One-dimensional (1D) geomechanical models, on the other hand, have log resolution along the wellbore but no penetration away from it—along the fracture length for instance. Combining borehole structural geology based on image data and finite elements (FE) geomechanics, we constructed and calibrated a 3D, high-resolution geomechanical model, including subseismic faults and natural fractures, over a 1,500- × 5,200- × 300-ft3 sector around a vertical pilot and a 3,700-ft lateral in the Fayetteville shale play. Compared to a 1D approach, we obtained a properly equilibrated stress field in 3D space, in which the effect of the structure, combined with that of material anisotropy and heterogeneity, are accounted for. These effects were observed to be significant on the stress field, both laterally and local to the faults and natural fractures. The model was used to derive and map in 3D space a series of geomechanically based attributes potentially indicative of hydraulic fracturing performance and risks, including stress barriers, fracture geometry attributes, near-well tortuosity, and the level of stress anisotropy. An interesting match was observed between some of the derived attributes and fracturing data—near-wellbore pressure drop and overall ease and difficulty to place a treatment—encouraging their use for perforation and stage placement or placement of the next nearby lateral. The model was also used to simulate hydraulic fracturing, taking advantage of such a 3D structural and geomechanical representation. It was shown that the structure and heterogeneity captured by the model had a significant impact on hydraulic fracture final geometry.
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Kumar, Goldy, et Vadim Shapiro. « Reduced Material Model of Composite Laminates for 3D Finite Element Analysis ». Dans ASME 2014 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/detc2014-35230.
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Laminate composites are widely used in automotive, aerospace, medical, and increasingly in consumer industries, due to their reduced weight, superior structural properties and cost-effectiveness. However, structural analysis of complex laminate structures remains challenging. 2D finite element methods based on plate and shell theories may be accurate and efficient, but they generally do not apply to the whole structure, and require identification and preprocessing (dimensional reduction) of the regions where the underlying assumptions hold. Differences in and limitations of theories for thin/thick plates and shells further complicate modeling and simulation of composites. Fully automated structural analysis using 3D elements with sufficiently high order basis functions is possible in principle, but is rarely practiced due to the significant increase in computational integration cost in the presence of a large number of laminate plies. We propose to replace the actual layup of the laminate structure by a simplified material model, allowing for a substantial reduction of the computational cost of 3D FEA. The reduced model, under the usual assumptions made in lamination theory, has the same constitutive relationship as the corresponding 2D plate model of the original laminate, but requires only a small fraction of computational integration costs in 3D FEA. We describe implementation of 3D FEA using the reduced material model in a meshfree system using second order B-spline basis functions. Finally, we demonstrate its validity by showing agreement between computed and known results for standard problems.
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Scarselli, Gennaro, Francesco Nicassio, Pierandrea Vergallo et Raffaele Vitolo. « Finite difference 3D model for structural health monitoring of single lap joints ». Dans Nondestructive Characterization and Monitoring of Advanced Materials, Aerospace, Civil Infrastructure, and Transportation XVI, sous la direction de Peter J. Shull, Tzuyang Yu, Andrew L. Gyekenyesi et H. Felix Wu. SPIE, 2022. http://dx.doi.org/10.1117/12.2616220.
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PENG, XIN, GAOFENG SU, ZHIQIANG CHEN et RAJA SENGUPTA. « STRUCTURAL DAMAGE DETECTION, LOCALIZATION, AND QUANTIFICATION VIA UAV-BASED 3D IMAGING ». Dans Structural Health Monitoring 2021. Destech Publications, Inc., 2022. http://dx.doi.org/10.12783/shm2021/36235.
Texte intégralRésumé :
Visual damage inspection for civil structures is a labor-intensive and timeconsuming task. We propose an autonomous UAV-based pipeline for crack and spalling detection, localization, and quantification. Through fusing 3-dimensional (3D) reconstruction and 2D damage detection after performing UAV-based imaging for an engineering structure, the process generates a damage-annotated 3D information model with rich metadata, including the size and type of damage and its location relative to the structure. The pipeline is composed of four steps: image acquisition via UAV, 3D scene reconstruction, crack/spalling detection and extraction using a deep neural network, and 3D damage localization and quantification. To validate this process, UAV images from three full-scale concrete columns are processed, and results are evaluated in this paper. The results demonstrate that the proposed pipeline can provide accurate and informative 3D condition mapping for civil structures. The authors envision that by employing this UAV-based automatic process, structural damage inspection can be conducted much frequently and rapidly with a significantly low cost.
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Zhao, Chengbi, Ming Ma et Owen Hughes. « Applying Strip Theory Based Linear Seakeeping Loads to 3D Full Ship Finite Element Models ». Dans ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-10124.
Texte intégralRésumé :
Panel based hydrodynamic analyses are well suited for transferring seakeeping loads to 3D FEM structural models. However, 3D panel based hydrodynamic analyses are computationally expensive. For monohull ships, methods based on strip theory have been successfully used in industry for many years. They are computationally efficient, and they provide good prediction for motions and hull girder loads. However, many strip theory methods provide only hull girder sectional forces and moments, such as vertical bending moment and vertical shear force, which are difficult to apply to 3D finite element structural models. For the few codes which do output panel pressure, transferring the pressure map from a hydrodynamic model to the corresponding 3D finite element model often results in an unbalanced structural model because of the pressure interpolation discrepancy. To obtain equilibrium of an imbalanced structural model, a common practice is to use the “inertia relief” approach to rebalance the model. However, this type of balancing causes a change in the hull girder load distribution, which in turn could cause inaccuracies in an extreme load analysis (ELA) and a spectral fatigue analysis (SFA). This paper presents a method of applying strip theory based linear seakeeping pressure loads to balance 3D finite element models without using inertia relief. The velocity potential of strip sections is first calculated based on hydrodynamic strip theories. The velocity potential of a finite element panel is obtained from the interpolation of the velocity potential of the strip sections. The potential derivative along x-direction is computed using the approach proposed by Salvesen, Tuck and Faltinsen. The hydrodynamic forces and moments are computed using direct panel pressure integration from the finite element structural panel. For forces and moments which cannot be directly converted from pressure, such as hydrostatic restoring force and diffraction force, element nodal forces are generated using Quadratic Programing. The equations of motions are then formulated based on the finite element wetted panels. The method results in a perfectly balanced structural model.
Rapports d'organisations sur le sujet "3D-structural model"
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Logan, C., D. R. Sharpe et H. A. J. Russell. Regional 3D structural model of the Oak Ridges Moraine and Greater Toronto area, southern Ontario : version 1.0. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2002. http://dx.doi.org/10.4095/213493.
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de Kemp, E. A., H. A. J. Russell, B. Brodaric, D. B. Snyder, M. J. Hillier, M. St-Onge, C. Harrison et al. Initiating transformative geoscience practice at the Geological Survey of Canada : Canada in 3D. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/331097.
Texte intégralRésumé :
Application of 3D technologies to the wide range of Geosciences knowledge domains is well underway. These have been operationalized in workflows of the hydrocarbon sector for a half-century, and now in mining for over two decades. In Geosciences, algorithms, structured workflows and data integration strategies can support compelling Earth models, however challenges remain to meet the standards of geological plausibility required for most geoscientific studies. There is also missing links in the institutional information infrastructure supporting operational multi-scale 3D data and model development. Canada in 3D (C3D) is a vision and road map for transforming the Geological Survey of Canada's (GSC) work practice by leveraging emerging 3D technologies. Primarily the transformation from 2D geological mapping, to a well-structured 3D modelling practice that is both data-driven and knowledge-driven. It is tempting to imagine that advanced 3D computational methods, coupled with Artificial Intelligence and Big Data tools will automate the bulk of this process. To effectively apply these methods there is a need, however, for data to be in a well-organized, classified, georeferenced (3D) format embedded with key information, such as spatial-temporal relations, and earth process knowledge. Another key challenge for C3D is the relative infancy of 3D geoscience technologies for geological inference and 3D modelling using sparse and heterogeneous regional geoscience information, while preserving the insights and expertise of geoscientists maintaining scientific integrity of digital products. In most geological surveys, there remains considerable educational and operational challenges to achieve this balance of digital automation and expert knowledge. Emerging from the last two decades of research are more efficient workflows, transitioning from cumbersome, explicit (manual) to reproducible implicit semi-automated methods. They are characterized by integrated and iterative, forward and reverse geophysical modelling, coupled with stratigraphic and structural approaches. The full impact of research and development with these 3D tools, geophysical-geological integration and simulation approaches is perhaps unpredictable, but the expectation is that they will produce predictive, instructive models of Canada's geology that will be used to educate, prioritize and influence sustainable policy for stewarding our natural resources. On the horizon are 3D geological modelling methods spanning the gulf between local and frontier or green-fields, as well as deep crustal characterization. These are key components of mineral systems understanding, integrated and coupled hydrological modelling and energy transition applications, e.g. carbon sequestration, in-situ hydrogen mining, and geothermal exploration. Presented are some case study examples at a range of scales from our efforts in C3D.
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Ravazdezh, Faezeh, Julio A. Ramirez et Ghadir Haikal. Improved Live Load Distribution Factors for Use in Load Rating of Older Slab and T-Beam Reinforced Concrete Bridges. Purdue University, 2021. http://dx.doi.org/10.5703/1288284317303.
Texte intégralRésumé :
This report describes a methodology for demand estimate through the improvement of load distribution factors in reinforced concrete flat-slab and T-beam bridges. The proposed distribution factors are supported on three-dimensional (3D) Finite Element (FE) analysis tools. The Conventional Load Rating (CLR) method currently in use by INDOT relies on a two-dimensional (2D) analysis based on beam theory. This approach may overestimate bridge demand as the result of neglecting the presence of parapets and sidewalks present in these bridges. The 3D behavior of a bridge and its response could be better modeled through a 3D computational model by including the participation of all elements. This research aims to investigate the potential effect of railings, parapets, sidewalks, and end-diaphragms on demand evaluation for purposes of rating reinforced concrete flat-slab and T-beam bridges using 3D finite element analysis. The project goal is to improve the current lateral load distribution factor by addressing the limitations resulting from the 2D analysis and ignoring the contribution of non-structural components. Through a parametric study of the slab and T-beam bridges in Indiana, the impact of selected parameters on demand estimates was estimated, and modifications to the current load distribution factors in AASHTO were proposed.
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Pellerin, Jeanne, Bruno Lévy et Guillaume Caumon. Topological control for isotropic remeshing of nonmanifold surfaces with varying resolution : application to 3D structural models. Cogeo@oeaw-giscience, septembre 2011. http://dx.doi.org/10.5242/iamg.2011.0158.
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Huang, Haohang, Erol Tutumluer, Jiayi Luo, Kelin Ding, Issam Qamhia et John Hart. 3D Image Analysis Using Deep Learning for Size and Shape Characterization of Stockpile Riprap Aggregates—Phase 2. Illinois Center for Transportation, septembre 2022. http://dx.doi.org/10.36501/0197-9191/22-017.
Texte intégralRésumé :
Riprap rock and aggregates are extensively used in structural, transportation, geotechnical, and hydraulic engineering applications. Field determination of morphological properties of aggregates such as size and shape can greatly facilitate the quality assurance/quality control (QA/QC) process for proper aggregate material selection and engineering use. Many aggregate imaging approaches have been developed to characterize the size and morphology of individual aggregates by computer vision. However, 3D field characterization of aggregate particle morphology is challenging both during the quarry production process and at construction sites, particularly for aggregates in stockpile form. This research study presents a 3D reconstruction-segmentation-completion approach based on deep learning techniques by combining three developed research components: field 3D reconstruction procedures, 3D stockpile instance segmentation, and 3D shape completion. The approach was designed to reconstruct aggregate stockpiles from multi-view images, segment the stockpile into individual instances, and predict the unseen side of each instance (particle) based on the partial visible shapes. Based on the dataset constructed from individual aggregate models, a state-of-the-art 3D instance segmentation network and a 3D shape completion network were implemented and trained, respectively. The application of the integrated approach was demonstrated on re-engineered stockpiles and field stockpiles. The validation of results using ground-truth measurements showed satisfactory algorithm performance in capturing and predicting the unseen sides of aggregates. The algorithms are integrated into a software application with a user-friendly graphical user interface. Based on the findings of this study, this stockpile aggregate analysis approach is envisioned to provide efficient field evaluation of aggregate stockpiles by offering convenient and reliable solutions for on-site QA/QC tasks of riprap rock and aggregate stockpiles.
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Kirchhoff, Helmut, et Ziv Reich. Protection of the photosynthetic apparatus during desiccation in resurrection plants. United States Department of Agriculture, février 2014. http://dx.doi.org/10.32747/2014.7699861.bard.
Texte intégralRésumé :
In this project, we studied the photosynthetic apparatus during dehydration and rehydration of the homoiochlorophyllous resurrection plant Craterostigmapumilum (retains most of the photosynthetic components during desiccation). Resurrection plants have the remarkable capability to withstand desiccation, being able to revive after prolonged severe water deficit in a few days upon rehydration. Homoiochlorophyllous resurrection plants are very efficient in protecting the photosynthetic machinery against damage by reactive oxygen production under drought. The main purpose of this BARD project was to unravel these largely unknown protection strategies for C. pumilum. In detail, the specific objectives were: (1) To determine the distribution and local organization of photosynthetic protein complexes and formation of inverted hexagonal phases within the thylakoid membranes at different dehydration/rehydration states. (2) To determine the 3D structure and characterize the geometry, topology, and mechanics of the thylakoid network at the different states. (3) Generation of molecular models for thylakoids at the different states and study the implications for diffusion within the thylakoid lumen. (4) Characterization of inter-system electron transport, quantum efficiencies, photosystem antenna sizes and distribution, NPQ, and photoinhibition at different hydration states. (5) Measuring the partition of photosynthetic reducing equivalents between the Calvin cycle, photorespiration, and the water-water cycle. At the beginning of the project, we decided to use C. pumilum instead of C. wilmsii because the former species was available from our collaborator Dr. Farrant. In addition to the original two dehydration states (40 relative water content=RWC and 5% RWC), we characterized a third state (15-20%) because some interesting changes occurs at this RWC. Furthermore, it was not possible to detect D1 protein levels by Western blot analysis because antibodies against other higher plants failed to detect D1 in C. pumilum. We developed growth conditions that allow reproducible generation of different dehydration and rehydration states for C. pumilum. Furthermore, advanced spectroscopy and microscopy for C. pumilum were established to obtain a detailed picture of structural and functional changes of the photosynthetic apparatus in different hydrated states. Main findings of our study are: 1. Anthocyan accumulation during desiccation alleviates the light pressure within the leaves (Fig. 1). 2. During desiccation, stomatal closure leads to drastic reductions in CO2 fixation and photorespiration. We could not identify alternative electron sinks as a solution to reduce ROS production. 3. On the supramolecular level, semicrystalline protein arrays were identified in thylakoid membranes in the desiccated state (see Fig. 3). On the electron transport level, a specific series of shut downs occur (summarized in Fig. 2). The main events include: Early shutdown of the ATPase activity, cessation of electron transport between cyt. bf complex and PSI (can reduce ROS formation at PSI); at higher dehydration levels uncoupling of LHCII from PSII and cessation of electron flow from PSII accompanied by crystal formation. The later could severe as a swift PSII reservoir during rehydration. The specific order of events in the course of dehydration and rehydration discovered in this project is indicative for regulated structural transitions specifically realized in resurrection plants. This detailed knowledge can serve as an interesting starting point for rationale genetic engineering of drought-tolerant crops.
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A SIMPLE METHOD FOR A RELIABLE MODELLING OF THE NONLINEAR BEHAVIOUR OF BOLTED CONNECTIONS IN STEEL LATTICE TOWERS. The Hong Kong Institute of Steel Construction, mars 2022. http://dx.doi.org/10.18057/ijasc.2022.18.1.6.
Texte intégralRésumé :
The behaviour of bolted connections in steel lattice transmission line towers affects their load-bearing capacity and failure mode. Bolted connections are commonly modelled as pinned or fixed joints, but their behaviour lies between these two extremes and evolves in a nonlinear manner. Accordingly, an accurate finite element modelling of the structural response of complete steel lattice towers requires the consideration of various nonlinear phenomena involved in bolted connexions, such as bolt slippage. In this study, a practical method is proposed for the modelling of the nonlinear response of steel lattice tower connections involving one or multiple bolts. First, the local load-deformation behaviour of single-bolt lap connections is evaluated analytically depending on various geometric and material parameters and construction details. Then, the predicted nonlinear behaviour for a given configuration serves as an input to a 2D/3D numerical model of the entire assembly of plates in which the bolted joints are represented as discrete elements. For comparison purposes, an extensive experimental study comprising forty-four tests were conducted on steel plates assembled with one or two bolts. This approach is also extended to simulate the behaviour of assemblies including four bolts and the obtained results are checked against experimental datasets from the literature. The obtained results show that the proposed method can predict accurately the response of a variety of multi-bolt connections. A potential application of the strategy developed in this paper could be in the numerical modelling of full-scale steel lattice towers, particularly for a reliable estimation of the displacements.
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SIMPLIFIED MODELLING OF NOVEL NON-WELDED JOINTS FOR MODULAR STEEL BUILDINGS. The Hong Kong Institute of Steel Construction, décembre 2021. http://dx.doi.org/10.18057/ijasc.2021.17.4.10.
Texte intégralRésumé :
Prefabricated modular steel (PFMS) construction is a more efficient and safe method of constructing a high-quality building with less waste material and labour dependency than traditional steel construction. It is indeed critical to have a precise and valuable intermodular joining system that allows for efficient load transfer, safe handling, and optimal use of modular units' strength. Thus, the purpose of this study was to develop joints using tension bolts and solid tenons welded into the gusset plate (GP). These joints ensured rigid and secure connectivity in both horizontal and vertical directions for the modular units. Using the three-dimensional (3D) finite element (FE) analysis software ABAQUS, the study investigated the nonlinear lateral structural performance of the joint and two-storey modular steel building (MSB). The solid element FE models of joints were then simplified by introducing connectors and beam elements to enhance computational efficiency. Numerous parameters indicated that column tenons were important in determining the joint's structural performance. Moreover, with a standard deviation (SD) of 0.025, the developed connectors and beam element models accurately predicted the structural behaviour of the joints. As a result of their simplification, these joints demonstrated effective load distribution, seismic performance, and ductility while reducing computational time, effort, and complexity. The validity of the FE analysis was then determined by comparing the results to the thirteen joint bending tests performed in the reference.
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SEISMIC PERFORMANCE OF SPATIAL STEEL BEAM-COLUMN CONNECTIONS. The Hong Kong Institute of Steel Construction, août 2022. http://dx.doi.org/10.18057/icass2020.p.125.
Texte intégralRésumé :
This paper presents a finite element analysis for spatial beam-column connections in steel frame to better understand the structural behavior of spatial connections. After the simulation and validation of experimental results, a total of 7 refined 3D models, including beam-to-column connections at different positions in the steel frame, were created and analyzed cyclically through the nonlinear finite element program ABAQUS to investigate the spatial coupling effect. The momentrotation relationships and TI index distribution across the width of beam flanges, were discussed in detail to elucidate the mechanical performance interaction between strong-axis and weak-axis connections. Results showed that there is obvious interaction between two beams in strong-axis or weak-axis connections, and the plane exterior connections has better hysteresis performance. While the interaction of strong-axis connection and weak-axis connection slightly affected each other’s hysteresis performance, and thus the coupling effect of spatial connections is not evident.