Academic literature on the topic 'Deformations of D-Structures'
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Journal articles on the topic "Deformations of D-Structures"
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Hassan, S. F. "O(d,d;R) deformations of complex structures and extended worldsheet supersymmetry." Nuclear Physics B 454, no. 1-2 (1995): 86–102. http://dx.doi.org/10.1016/0550-3213(95)00384-5.
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Cingolani, Matteo, Gioia Fusaro, Giulia Fratoni, and Massimo Garai. "Influence of thermal deformations on sound absorption of three-dimensional printed metamaterials." Journal of the Acoustical Society of America 151, no. 6 (2022): 3770–79. http://dx.doi.org/10.1121/10.0011552.
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Acoustic metamaterials (AMMs) are designed with complex geometrical shapes to obtain unconventional sound-absorbing performances. As additive manufacturing is particularly suited to print complex structures in a more straightforward and controllable way, AMMs often exploit three-dimensional (3-D) printing techniques. However, when exposed to different temperature conditions, such structures can be affected by geometrical deformations, especially when they are polymer-based. This can cause a mismatch between the experimental data and the expected theoretical performance; therefore, it is important to take thermal effects into account. The present paper investigates the influence of thermal deformations on the sound absorption of three geometries: a coplanar spiral tube, a system with double coiled resonators, and a neck-embedded resonator. Measurements were performed on each 3-D printed specimen in the impedance tube after the samples had been placed in a climate chamber to modify the temperature settings (T = 10–50 °C). Numerical models, validated on the measurements, were employed to quantify the geometrical deformation of AMM structures through a multiphysics approach, highlighting the effects of thermal stress on the acoustic behavior. The main outcomes prove that the frequency shifts of sound absorption peaks depend on temperature configurations and follow exponential regressions, in accordance with previous literature on polymeric materials.
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AKTAY, Şirin. "D-Homothetic Deformations and Almost Paracontact Metric Manifolds." Fundamentals of Contemporary Mathematical Sciences 5, no. 1 (2023): 1–14. http://dx.doi.org/10.54974/fcmathsci.1240849.
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In this study, we determine some of the classes of almost paracontact metric structures which are invariant under D-homothetic deformations. We write the Riemannian curvature tensor, the Ricci tensor and the scalar curvature when the characteristic vector field is Killing. In addition, we give examples.
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KAPUSTIN, ANTON. "TOPOLOGICAL STRINGS ON NONCOMMUTATIVE MANIFOLDS." International Journal of Geometric Methods in Modern Physics 01, no. 01n02 (2004): 49–81. http://dx.doi.org/10.1142/s0219887804000034.
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We identify a deformation of the N=2 supersymmetric sigma model on a Calabi–Yau manifold X which has the same effect on B-branes as a noncommutative deformation of X. We show that for hyperkähler X such deformations allow one to interpolate continuously between the A-model and the B-model. For generic values of the noncommutativity and the B-field, properties of the topologically twisted sigma-models can be described in terms of generalized complex structures introduced by N. Hitchin. For example, we show that the path integral for the deformed sigma-model is localized on generalized holomorphic maps, whereas for the A-model and the B-model it is localized on holomorphic and constant maps, respectively. The geometry of topological D-branes is also best described using generalized complex structures. We also derive a constraint on the Chern character of topological D-branes, which includes A-branes and B-branes as special cases.
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Eriksen, Eivind. "Computing Noncommutative Deformations of Presheaves and Sheaves of Modules." Canadian Journal of Mathematics 62, no. 3 (2010): 520–42. http://dx.doi.org/10.4153/cjm-2010-015-6.
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AbstractWe describe a noncommutative deformation theory for presheaves and sheaves of modules that generalizes the commutative deformation theory of these global algebraic structures and the noncommutative deformation theory of modules over algebras due to Laudal.In the first part of the paper, we describe a noncommutative deformation functor for presheaves of modules on a small category and an obstruction theory for this functor in terms of global Hochschild cohomology. An important feature of this obstruction theory is that it can be computed in concrete terms in many interesting cases.In the last part of the paper, we describe a noncommutative deformation functor for quasi-coherent sheaves of modules on a ringed space (X,𝒜). We show that for any good A-affine open cover U of X, the forgetful functor QCoh𝒜 → PreSh(U,𝒜) induces an isomorphism of noncommutative deformation functors.Applications. We consider noncommutative deformations of quasi-coherent 𝒜-modules on X when (X,𝒜) = (X,𝒪X) is a scheme or (X,𝒜) = (X,𝒟) is a D-scheme in the sense of Beilinson and Bernstein. In these cases, we may use any open affine cover of X closed under finite intersections to compute noncommutative deformations in concrete terms using presheaf methods. We compute the noncommutative deformations of the left 𝒟X-module 𝒟X when X is an elliptic curve as an example.
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Correa, Francisco, and Olaf Lechtenfeld. "Algebraic integrability of PT -deformed Calogero models." Journal of Physics: Conference Series 2038, no. 1 (2021): 012007. http://dx.doi.org/10.1088/1742-6596/2038/1/012007.
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Abstract We review some recents developments of the algebraic structures and spectral properties of non-Hermitian deformations of Calogero models. The behavior of such extensions is illustrated by the A 2 trigonometric and the D 3 angular Calogero models. Features like intertwining operators and conserved charges are discussed in terms of Dunkl operators. Hidden symmetries coming from the so-called algebraic integrability for integral values of the coupling are addressed together with a physical regularization of their action on the states by virtue of a PT -symmetry deformation.
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Yuge, K., N. Iwai, and N. Kikuchi. "Optimization of 2-D structures subjected to nonlinear deformations using the homogenization method." Structural Optimization 17, no. 4 (1999): 286–99. http://dx.doi.org/10.1007/bf01207005.
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He, Kuan, Youfeng Zou, Zhigang Han, and Jilei Huang. "Time-Series InSAR Technology for Monitoring and Analyzing Surface Deformations in Mining Areas Affected by Fault Disturbances." Remote Sensing 16, no. 24 (2024): 4811. https://doi.org/10.3390/rs16244811.
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Faults, as unique geological structures, disrupt the mechanical connections between rock masses. During coal mining, faults in the overlying strata can disturb the original stress balance, leading to fault activation and altering the typical subsidence patterns. This can result in abnormal ground deformation and significant damage to surface structures, posing a serious geological hazard in mining areas. This study examines the influence of a known fault (F13 fault) on ground subsidence in the Wannian Mine of the Fengfeng Mining Area. We utilized 12 Sentinel-1A images and applied SBAS-InSAR, StaMPS-InSAR, and DS-InSAR time-series InSAR methods, alongside the D-InSAR method, to investigate surface deformations caused by the F13 fault. The monitoring accuracy of these methods was evaluated using leveling measurements from 28 surface movement observation stations. In addition, the density of effective monitoring points and the relative strengths and limitations of the three time-series methods were compared. The findings indicate that, in low deformation areas, DS-InSAR has a monitoring accuracy of 7.7 mm, StaMPS-InSAR has a monitoring accuracy of 16.4 mm, and SBAS-InSAR has an accuracy of 19.3 mm.
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Shaw, Amit, and D. Roy. "Improved Procedures for Static and Dynamic Analyses of Wrinkled Membranes." Journal of Applied Mechanics 74, no. 3 (2006): 590–94. http://dx.doi.org/10.1115/1.2338057.
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An analysis of large deformations of flexible membrane structures within the tension field theory is considered. A modification of the finite element procedure by Roddeman et al. (Roddeman, D. G., Drukker, J., Oomens, C. W. J., Janssen, J. D., 1987, ASME J. Appl. Mech. 54, pp. 884–892) is proposed to study the wrinkling behavior of a membrane element. The state of stress in the element is determined through a modified deformation gradient corresponding to a fictive nonwrinkled surface. The new model uses a continuously modified deformation gradient to capture the location orientation of wrinkles more precisely. It is argued that the fictive nonwrinkled surface may be looked upon as an everywhere-taut surface in the limit as the minor (tensile) principal stresses over the wrinkled portions go to zero. Accordingly, the modified deformation gradient is thought of as the limit of a sequence of everywhere-differentiable tensors. Under dynamic excitations, the governing equations are weakly projected to arrive at a system of nonlinear ordinary differential equations that is solved using different integration schemes. It is concluded that implicit integrators work much better than explicit ones in the present context.
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Vilfayeau, Jerome, David Crépin, François Boussu, Damien Soulat, and Philippe Boisse. "Numerical Modelling of the Weaving Process for Textile Composite." Key Engineering Materials 554-557 (June 2013): 472–77. http://dx.doi.org/10.4028/www.scientific.net/kem.554-557.472.
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Due to advancements made in 3D weaving process [1] and, in order to develop 3D textile structure as reinforcement of composite material for aeronautic application, a good prediction of the geometry and the mechanical properties of the 3D woven unit cell is required. Due to the complexity of these textile architectures, realistic geometric representations [2] of fabrics are often difficult to obtain especially for 3D woven fabrics, but these descriptions are necessary to define meshes for finite element computation [3]. At present, existing tools which model and define, early at a mesoscopic scale [4], the architecture of 3D fabrics don’t take into account the influence of the manufacturing process on the shape modification of the textile structure. Some numerical model exists for the braiding process [5] and the knitting process [6], but not yet for the weaving process. During the manufacturing process, fibres are subjected to significant deformations due to loads from the component of the loom or from the friction with the others fibres. These significant deformations lead to mechanical strength losses of the fabric. A numerical model of the different steps of the weaving process could predict these significant deformations and their influence on the geometry of the textile architecture. Thus, the objective of the NUMTISS project is to develop a numerical model of the deformation of the yarn during the weaving process. For the numerical modelling of the weaving process developed in finite element method, we considered all loom elements like rigid solid, and we will make the assumption that yarns are transverse isotropic elastic materials. Simulations of the process for a plain weave, a twill 2-2 and a satin 8 fabric have already been performed, as well as the simulation of orthogonal warp interlock structures. Then, to understand the kinematic motions of weaving process, the tracking of some strategic elements on the industrial weaving loom (reed, heddles, rapier,..) have been carried out. The tracking obtained from the video of the high speed camera will help us to define the numerical model of the weaving kinematic closer to reality. Correlations between numerical results and specific structures in glass fibres produced on the loom will be presented. The influence of each step of the manufacturing process on the characteristics of the textile structure could be analyzed [1]X. Chen, L. W. Taylor, L. J.Tsai. ”An overview on fabrication of three-dimensional woven textile preforms for composites”. Textile Research Journal, 2011, 81(9) 932–944 [2] SV Lomov, G Perie, DS Ivanov, I Verpoest and D Marsal. “Modeling three-dimensional fabrics and three-dimensional reinforced composites: challenges and solutions”. Textile Research Journal, 2011, 81(1) 28–41 [3] E. De Luycker, F. Morestin, P. Boisse, D. Marsal. « Simulation of 3D interlock composite performing”. Composite Structures, Volume 88, Issue 4, May 2009, Pages 615-623. [4] M. Ansar, W. Xinwei, Z. Chouwei. “Modeling strategies of 3D woven composites: A review”. Composite Structures 93 (2011) 1947–1963. [5] A. K. Pickett, J. Sirtautas, et A. Erber. « Braiding simulation and prediction of mechanical properties”. Applied Composite Materials, 2009. [6] M. Duhovic, D. Bhattacharyya. “Simulating the deformation mechanisms of knitted fabric composites”. Composites Part A : Applied Science and Manufacturing, 2006.
Dissertations / Theses on the topic "Deformations of D-Structures"
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ROSSI, FEDERICO ALBERTO. "D-Complex Structures on Manifolds: Cohomological properties and deformations." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2013. http://hdl.handle.net/10281/41976.
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In questa tesi studiamo alcune proprietà delle "Varietà Doppie" o D-Varietà. In particolare studiamo la teoria delle deformazioni di D-Strutture e di D-Strutture CR, e troviamo una condizione che è equivalente alla classica condizione di Maurer-Cartan che descrive l'integrabilità di deformazioni di D-Strutture. Successivamente prestiamo attenzione alla coomologia delle D-Varietà, provando che una versione D-complessa del del-delbar-Lemma non può essere vera per D-varietà compatte. Inoltre sono stabilite alcune proprietà di sottogruppi speciali della coomologia di de-Rham, ottenute studiando il loro comportamento sotto l'azione di deformazioni. Infine, un risultato riguardante le sottovarietà Lagrangiane minimali dovuto ad Harvey e Lawson riguardante le varietà D-Kahler Ricci-Piatte è generalizzato a una classe di varietà simplettiche quasi D-complesse.<br>We study some properties of Double Manifold, or D-Manifolds. In particular, we study of deformations of D-structures and of CR D-structures, and we found a condition which is equivalent to the classical Maurer-Cartan equation describing the integrability of the deformations. We also focus on the cohomological properties of D-Manifold, showing that a del-delbar-Lemma can not hold for any compact D-Manifold. We also state some properties of special subgroups of de-Rham cohomology, studing also their behaviour under small deformations. Finally, a result by Harvey and Lawson about the minimal Lagrangian Submanifold of a D-Kahler Ricci-flat manifold is generalized to the case of a special almost D-complex symplectic manifold.
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Recio, Molina Juan Antonio. "Hydraulic stability of geotextile sand containers for coastal structures effect of deformations and stability formulae." Clausthal-Zellerfeld Papierflieger, 2007. http://d-nb.info/987276026/04.
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Bassa, Bruno. "Contribution à l’étude d’éléments finis de type coque sans degrés de liberté en rotation ou à formulation solide pour des simulations numériques de l’emboutissage et du retour élastique." Thesis, Lyon, INSA, 2011. http://www.theses.fr/2011ISAL0113/document.
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La thèse présente une méthodologie pour construire des éléments finis de type « solide-coque » avec intégration réduite en vue des applications à la simulation de la mise en forme tel que l’emboutissage des tôles où ces éléments finis doivent présenter de bonnes aptitudes à modéliser la flexion mais également les situations de laminage de la tôle. A partir des éléments volumiques à 8 nœuds et 3 degrés de liberté par nœud (les 3 composantes du déplacement), un neuvième nœud est rajouté au centre de l’élément. Ce neuvième nœud n’est pourvu que d’un seul degré de liberté, le déplacement le long de la direction de l’épaisseur. Cette direction privilégiée a un nombre de points d’intégration supérieur ou égal à 3 mais l’intégration est réduite au centre de l’élément diminuant très sensiblement les temps CPU par rapport à une intégration complète. Un soin particulier a été pris pour contrôler tous les modes à énergie nulle dus à l’intégration réduite. Ce nœud supplémentaire permet une distribution linéaire de la déformation normale. Avec les lois de comportement complètement 3D ces nouveaux éléments solide-coque donnent des résultats similaires en flexion à ceux obtenus avec des éléments coques et état plan de contrainte. Le neuvième nœud joue le rôle d’un paramètre supplémentaire pour l’interpolation quadratique du déplacement dans la direction de l’épaisseur. Ce degré de liberté a une signification physique et un effort équivalent à une pression normale peut être prescrit. Dans les situations de pression normale et dans le cas du contact, la contrainte normale obtenue est physique ce qui n’est pas le cas de nombreux éléments solide-coque de la littérature. Le pincement ou le laminage des tôles est correctement modélisé. Pour valider ces éléments, un module d’emboutissage en U avec passage et laminage de la bande de tôle sur des rouleaux a été construit au laboratoire. La comparaison entre les efforts d’emboutissage calculés et mesurés est très bonne ainsi que la géométrie des bandes de tôle obtenue après retour élastique<br>This thesis presents a methodology for developing under-integrated “solid-shell” finite elements for sheet forming simulations like deep drawing where these elements must offer a bending capability and sheet thinning conditions as well. Starting from 8-node elements endowing three degrees of freedom per node (three displacement components), a ninth node is added at the centre of the element. This extra node has just one degree of freedom: a displacement along the ‘thickness’ direction. Several integration points are distributed along this privileged direction (5 points, generally) but the in-plane reduced integration at the centre of the element decreases CPU costs compared to a full integration. A special care has been taken to control all zero-energy modes due to the reduced integration. This additional node allows a linear distribution of the normal strain. With fully-3D constitutive laws, these new solid-shell elements give similar bending results as those obtained with shell elements and a plane stress state hypothesis. This ninth node acts as an additional parameter for the quadratic interpolation of the displacement in the ‘thickness’ direction. The corresponding degree of freedom has a physical meaning and a force, equivalent to a normal pressure for instance, may be prescribed. In situations of a normal pressure and in the case of contact, the obtained normal stress is physically defined, which is not the case for many solid-shell elements found in the literature. The pinching (or the thinning) of sheets is properly modelled. To validate these elements, an apparatus for U-drawing tests with ironing or thinning on strip sheets has been built in the laboratory. The comparison between numerical and experimental punch force during sheet forming is pretty good as well as the geometry of blank after springback
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Rollenske, Sönke [Verfasser]. "Nilmanifolds : complex structures, geometry and deformations / Sönke Rollenske." 2007. http://d-nb.info/985385464/34.
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Stelzig, Philipp Emanuel [Verfasser]. "Homogenization of many-body structures subject to large deformations and noninterpenetration / Philipp Emanuel Stelzig." 2009. http://d-nb.info/1000121763/34.
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Recio, Molina Juan Antonio [Verfasser]. "Hydraulic stability of geotextile sand containers for coastal structures : effect of deformations and stability formulae / von Juan Antonio Recio Molina." 2008. http://d-nb.info/987929720/34.
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Yi-HsuanLi and 李怡萱. "R ＆ D of Gradient Structure Design Effects on Plastic Deformation of Ti-6Al-4V Porous Materials." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/xen4cc.
Full textBooks on the topic "Deformations of D-Structures"
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Rozenblyum, Nick, and Dennis Gaitsgory. Study in Derived Algebraic Geometry : Volume II: Deformations, Lie Theory and Formal Geometry. American Mathematical Society, 2020.
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Study in Derived Algebraic Geometry : Volume II: Deformations, Lie Theory and Formal Geometry. American Mathematical Society, 2017.
Find full textBook chapters on the topic "Deformations of D-Structures"
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Oral S.Ü., Çetin K.O., Erol O., İnci G., and Delice M. "Performance assessment of Izmirspor metro station." In Proceedings of the 15th European Conference on Soil Mechanics and Geotechnical Engineering. IOS Press, 2011. https://doi.org/10.3233/978-1-60750-801-4-1541.
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Within the scope of this manuscript, 3-D finite element assessments performed for Izmir-Turkey Metro Project, &Idot;zmirspor Station will be presented with field ground deformation monitoring data for comparison purposes. Metro Tunnels were constructed using the New Austrian Method (NATM) and excavation of Izmirspor station structure was performed by cut and cover. The Station judged to be very critical and difficult to execute due to its relatively shallow depth, proximity to residential structures and complex geometry consisting of elevator tunnels, shafts, station tunnels and inclined stair tunnels. For the purpose of monitoring the performance of existing structures, a detailed monitoring program was executed including but not limited to topographical surveys, inclinometer and extensometer measurements. Predictions of the numerical assessment are judged to be consistent with monitored ground deformations. No significant structural performance problems were encountered at existing structures due to executed underground metro station construction. This is most part due to carefully tailored excavation and construction support sequences along with relatively competent nature of foundation rock/soil.
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Tanaka, Yoshiyuki, Volker Klemann, and Zdeněk Martinec. "An Estimate of the Effect of 3D Heterogeneous Density Distribution on Coseismic Deformation Using a Spectral Finite-Element Approach." In International Association of Geodesy Symposia. Springer Berlin Heidelberg, 2023. http://dx.doi.org/10.1007/1345_2023_236.
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AbstractThe advancement of the Global Geodetic Observing System (GGOS) has enabled monitoring of mass transport and solid-Earth deformation processes with unprecedented accuracy. Coseismic deformation is modelled as an elastic response of the solid Earth to an internal dislocation. Self-gravitating spherical Earth models can be employed in modelling regional to global scale deformations. Recent seismic tomography and high-pressure/high-temperature experiments have revealed finer-scale lateral heterogeneities in the elasticity and density structures within the Earth, which motivates us to quantify the effects of such finer structures on coseismic deformation. To achieve this, fully numerical approaches including the Finite Element Method (FEM) have often been used. In our previous study, we presented a spectral FEM, combined with an iterative perturbation method, to consider lateral heterogeneities in the bulk and shear moduli for surface loading. The distinct feature of this approach is that the deformation of the entire sphere is modelled in the spectral domain with finite elements dependent only on the radial coordinate. By this, self-gravitation can be treated without special treatments employed when using an ordinary FEM. In this study, we extend the formulation so that it can deal with lateral heterogeneities in density in the case of coseismic deformation. We apply this approach to a longer-wavelength vertical deformation due to a large earthquake. The result shows that the deformation for a laterally heterogeneous density distribution is suppressed mainly where the density is larger, which is consistent with the fact that self-gravitation reduces longer-wavelength deformations for 1-D models. The effect on the vertical displacement is relatively small, but the effect on the gravity change could amount to the same order of magnitude of a given heterogeneity if the horizontal scale of the heterogeneity is large enough.
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Mannacio, Francesco, Fabrizio Di Marzo, Marco Gaiotti, Massimo Guzzo, Cesare Mario Rizzo, and Marco Venturini. "Shock Characterization of Fiberglass Composite Laminates: Numerical and Experimental Comparison." In Progress in Marine Science and Technology. IOS Press, 2022. http://dx.doi.org/10.3233/pmst220048.
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When subjected to a no contact underwater explosions (UNDEX), naval composite structures show highly nonlinear deformations. In this paper, fiberglass composite laminates are characterized dynamically. Experimentally, modal analyses are carried out to determine the modal parameters of the specimens, while dedicated shock tests are performed using the MIL S 901 D Medium Weight Shock Machine to measure their shock deformations. Numerically, finite element model is built up, running both modal and implicit dynamic analyses to predict the structural response of different E-Glass laminates. In the end, results obtained by calculations are compared with experimental data, validating the model.
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Klokočník, Jaroslav, Aleš Bezděk, and Jan Kostelecký. "Gravity field aspects for identification of cosmic impact structures on Earth." In In the Footsteps of Warren B. Hamilton: New Ideas in Earth Science. Geological Society of America, 2022. http://dx.doi.org/10.1130/2021.2553(21).
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ABSTRACT We studied the following proven as well as hypothetical impact craters (among others), and some of the relevant results are reviewed in this chapter: (1) a hypothetical impact structure in Saginaw Bay, Great Lakes, Michigan; (2) a putative impact crater basin under the ice of Antarctica in Wilkes Land; (3) two recently discovered subglacial impact craters in Greenland; (4) a possible huge impact crater in Kotuykanskaya in a remote area of Siberia near the proven impact crater Popigai; and (5) a hypothetical impact object Burckle on the bottom of the Indian Ocean. They were tested using the gravity data derived from the recent gravity field model EIGEN 6C4 (with ground resolution of ~9 km). Our method is novel; we introduce gravity aspects (descriptors) to augment traditional gravity anomalies. The following gravity aspects were used: (a) gravity disturbances/anomalies, (b) second derivatives of the disturbing potential (the Marussi tensor), (c) two of three gravity invariants, (d) their specific ratio (known as 2D factor), (e) strike angles, and (f) virtual deformations. These gravity aspects are sensitive in various ways to the underground density contrasts. They describe the underground structures (not only the craters) more carefully and in more detail than the traditional gravity anomalies could do alone. Our results support geological evidence of the impact craters found by others in many cases or suggest new impact places for further study.
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Ogawa, Yujiro, and Shin’ichi Mori. "Gravitational sliding or tectonic thrusting?: Examples and field recognition in the Miura-Boso subduction zone prism." In Plate Tectonics, Ophiolites, and Societal Significance of Geology: A Celebration of the Career of Eldridge Moores. Geological Society of America, 2021. http://dx.doi.org/10.1130/2021.2552(10).
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ABSTRACT Discrimination between gravity slides and tectonic fold-and-thrust belts in the geologic record has long been a challenge, as both have similar layer shortening structures resulting from single bed duplication by thrust faults of outcrop to map scales. Outcrops on uplifted benches within the Miocene to Pliocene Misaki accretionary unit of Miura-Boso accretionary prism, Miura Peninsula, central Japan, preserve good examples of various types of bedding duplication and duplex structures with multiple styles of folds. These provide a foundation for discussion of the processes, mechanisms, and tectonic implications of structure formation in shallow parts of accretionary prisms. Careful observation of 2-D or 3-D and time dimensions of attitudes allows discrimination between formative processes. The structures of gravitational slide origin develop under semi-lithified conditions existing before the sediments are incorporated into the prism at the shallow surfaces of the outward, or on the inward slopes of the trench. They are constrained within the intraformational horizons above bedding-parallel detachment faults and are unconformably covered with the superjacent beds, or are intruded by diapiric, sedimentary sill or dike intrusions associated with liquefaction or fluidization under ductile conditions. The directions of vergence are variable. On the other hand, layer shortening structure formed by tectonic deformation within the accretionary prism are characterized by more constant styles and attitudes, and by strong shear features with cataclastic textures. In these structures, the fault surfaces are oblique to the bedding, and the beds are systematically duplicated (i.e., lacking random styles of slump folds), and they are commonly associated with fault-propagation folds. Gravitational slide bodies may be further deformed at deeper levels in the prism by tectonism. Such deformed rocks with both processes constitute the whole accretionary prism at depth, and later may be deformed, exhumed to shallow levels, and exposed at the surface of the trench slope, where they may experience further deformation. These observations are not only applicable in time and space to large-scale thrust-and-fold belts of accretionary prism orogens, but to small-scale examples. If we know the total 3-D geometry of geologic bodies, including the time and scale of deformational stages, we can discriminate between gravitational slide and tectonic formation of each fold-and-thrust belt at the various scales of occurrence.
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Lin Wei-te and Robb Richard A. "Patient Specific Physics-based Model for Interactive Visualization of Cardiac Dynamics." In Studies in Health Technology and Informatics. IOS Press, 2000. https://doi.org/10.3233/978-1-60750-914-1-182.
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Cardiac disorders result mainly from defects in cardiac structure or failure to generate and regulate electrical impulses. Knowledge of the structure, motion patterns, local deformation, and associated electrical activation patterns of the heart is necessary for precise diagnosis and treatment. Electrical and mechanical performance of the heart is strongly influenced by the anisotropic nature of myocardial tissue. Diffusion-encoded MR imaging provides in vivo myocardial fiber track information that can be used for precise simulation of cardiac conduction and contraction. We propose a method that incorporates such fiber track information with a physics-based deformable model to realistically simulate cardiac contraction and subsequent relaxation. The simulation aims to reproduce the myocardial deformation during the heartbeat. The system allows interactive visualization of dynamic 3-D heart structures during the cardiac cycle. In procedures such as catheter ablation, the interactive 4-D model provides updated anatomy and physiology of the patient&apos;s heart simultaneously, and can be used to guide the procedure for efficient targeting of the treatment regions.
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Hosseinzadeh, Saeed, and Kristjan Tabri. "Numerical Investigation of Hydroelastic Response of a Three-Dimensional Deformable Hydrofoil." In Progress in Marine Science and Technology. IOS Press, 2020. http://dx.doi.org/10.3233/pmst200029.
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The present study is concerned with the numerical simulation of Fluid-Structure Interaction (FSI) on a deformable three-dimensional hydrofoil in a turbulent flow. The aim of this work is to develop a strongly coupled two-way fluid-structure interaction methodology with a sufficiently high spatial accuracy to examine the effect of turbulent and cavitating flow on the hydroelastic response of a flexible hydrofoil. A 3-D cantilevered hydrofoil with two degrees-of-freedom is considered to simulate the plunging and pitching motion at the foil tip due to bending and twisting deformation. The defined problem is numerically investigated by coupled Finite Volume Method (FVM) and Finite Element Method (FEM) under a two-way coupling method. In order to find a better understanding of the dynamic FSI response and stability of flexible lifting bodies, the fluid flow is modeled in the different turbulence models and cavitation conditions. The flow-induced deformation and elastic response of both rigid and flexible hydrofoils at various angles of attack are studied. The effect of three-dimension body, pressure coefficient at different locations of the hydrofoil, leading-edge and trailing-edge deformation are presented and the results show that because of elastic deformation, the angle of attack increases and it lead to higher lift and drag coefficients. In addition, the deformations are generally limited by stall condition and because of unsteady vortex shedding, the post-stall condition should be considered in FSI simulation of deformable hydrofoil. To evaluate the accuracy of the numerical model, the present results are compared and validated against published experimental data and showed good agreement.
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Cameron B.M. and Robb R.A. "Patient Specific Dynamic Geometric Models From Sequential Volumetric Time Series Image Data." In Studies in Health Technology and Informatics. IOS Press, 2004. https://doi.org/10.3233/978-1-60750-942-4-40.
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Generating patient specific dynamic models is complicated by the complexity of the motion intrinsic and extrinsic to the anatomic structures being modeled. Using a physics-based sequentially deforming algorithm, an anatomically accurate dynamic four-dimensional model can be created from a sequence of 3-D volumetric time series data sets [1]. While such algorithms may accurately track the cyclic non-linear motion of the heart, they generally fail to accurately track extrinsic structural and non-cyclic motion. To accurately model these motions, we have modified a physics-based deformation algorithm to use a meta-surface defining the temporal and spatial maxima of the anatomic structure as the base reference surface. A mass-spring physics-based deformable model, which can expand or shrink with the local intrinsic motion, is applied to the metasurface, deforming this base reference surface to the volumetric data at each time point. As the meta-surface encompasses the temporal maxima of the structure, any extrinsic motion is inherently encoded into the base reference surface and allows the computation of the time point surfaces to be performed in parallel. The resultant 4-D model can be interactively transformed and viewed from different angles, showing the spatial and temporal motion of the anatomic structure. Using texture maps and per-vertex coloring, additional data such as physiological and/or biomechanical variables (e.g., mapping electrical activation sequences onto contracting myocardial surfaces) can be associated with the dynamic model, producing a 5-D model. For acquisition systems that may capture only limited time series data (e.g., only images at end-diastole/end-systole or inhalation/exhalation), this algorithm can provide useful interpolated surfaces between the time points. Such models help minimize the number of time points required to usefully depict the motion of anatomic structures for quantitative assessment of regional dynamics.
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Tsutsumi Yohei, Otani J., Mukunoki T., Chevalier B., Takano D., and Hazarika H. "Direct shear behavior of sand and tire chips using X-ray CT and DEM simulation." In Deformation Characteristics of Geomaterials. IOS Press, 2011. https://doi.org/10.3233/978-1-60750-822-9-746.
Full textAbstract:
One cost effective application of mixed sand with tire chips is to use them behind retaining structures as reducing earth pressure and to use its highly permeable nature of this type of materials as an agent for reducing liquefaction induced deformation. However, the precise mechanical properties of tire chips and mixed sand with tire chips have not been clarified yet. The objective of this paper is to investigate the shear behavior of tire chips and mixed sand with tire chips. First of all, the direct shear test which is one of the typical tests to obtain strength and deformation characteristic of granular materials was conducted for tire chips, sand and mixed sand with tire chips. Using X-ray CT, three dimensional behaviors of the materials were investigated without any destructions. In order to discuss the deformation and strain from the CT images, one of the common techniques on image analysis called Particle Image Velocimetry (PIV) was used. Here, the distributions of the displacement vectors, shear strain and volumetric strain were measured in each shear displacement level. These direct shear behaviors were also simulated using 3-D Discrete Element Method (DEM) and compared to the experimental results. Finally, the mechanical properties such as deformation and failure in the materials of tire chips and mixed sand with tire chips were precisely discussed based on all the results.
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Chen, Chuanmin, Fuyu Wang, and Weijie Yang. "First Principles Study of Different Atomic Exposure Terminals for Cu Adsorption on the Attapulgite (200) Surface." In Advances in Transdisciplinary Engineering. IOS Press, 2023. http://dx.doi.org/10.3233/atde230323.
Full textAbstract:
The geometric structure, electronic structure, and charge transfer of transition metal Cu atoms adsorbed on different adsorption sites on three different termination surfaces (Mg/Al-O, Si1-O, and Si2-O) of Attapulgite (ATP) (200) slab were systematically studied by density functional theory (DFT) calculation method. The calculated results show that the adsorption energy of Cu adsorbed on the O atom Hcp site of the ATP (200) Mg/Al-O termination surface has the smallest adsorption energy and the most stable adsorption structure; the calculations and analysis of the density of states reveal that the strong p-d orbital hybridization occurs between Cu-O at the best adsorption site on the termination surface of ATP (200) Mg/Al-O, which makes the surface adsorption system very stable; through the calculation and analysis of Bader charge and deformation charge density, it is found that there is a significant charge transfer between the Cu atom and the adjacent O atom, and an open electron-poor region is formed above the Cu atom, which improves the ability of the ATP (200) surface to accept electrons. The calculated results are in good agreement with the experiments and effectively reveal the microscopic mechanism of the Cu-loaded modified ATP catalyst.
Conference papers on the topic "Deformations of D-Structures"
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Swaisgood, Logan, and Anubhav Datta. "Towards a 3-D Fluid-Structure Interface for Helicopter Rotors." In Vertical Flight Society 81st Annual Forum and Technology Display. The Vertical Flight Society, 2025. https://doi.org/10.4050/f-0081-2025-242.
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The emergence of three-dimensional Computational Structural Dynamics for helicopter rotors warrants the development of a higher fidelity fluid-structure interface that can replace the one-dimensional sectional airload interface commonly used for coupled analysis with Computational Fluid Dynamics. Three methods of progressively higher fidelity are examined for imposing airloads onto the structure. These are defined as level-III, II, and I, based on fluid stresses, patch forces, and sectional airloads (baseline), respectively. A model problem investigating a 3-D cylindrical shell with large deformations near the boundaries is used to verify the methods. The patch force interface (level-II) approaches the stress interface (level-III) when the mesh is highly refined. Level-I (baseline) produces no solution at all (or zero solution). Level-II is then applied to a UH-60A-like rotor and compared with level-I. Only a forced response was carried out, not a full-fledged trim solution. For this practical problem, severe mismatches of the fluid and structural meshes required a special algorithm to impose the patch forces onto the structure. The key conclusion was that a higher fidelity interface is indeed feasible for rotors, and level-II appears to be the most convenient. Even though axial (bending) stresses showed approximately 5% difference from the baseline airloads interface, the errors in shear stresses were dramatic, rising to 100% and higher inside the main load bearing parts of the rotor across its mid-span.
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Garg, Ajay. "2-D Finite Element Analysis of Engineering Components." In ASME 1995 15th International Computers in Engineering Conference and the ASME 1995 9th Annual Engineering Database Symposium collocated with the ASME 1995 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1995. http://dx.doi.org/10.1115/cie1995-0741.
Full textAbstract:
Abstract Design and analysis of engineering components can be categorized under the theory of continuum mechanics, plates/shells or beams. Closed form solutions for determining deformations and stresses are available for simple structures with simple boundary conditions. In the cases of complex structures, boundary conditions and loads, analytical solutions are not readily available. Finite element analysis (FEA) can be performed to resolve the simulation barrier of these analytically indeterminate structures. Similar to analytical approach, FEA can simulate the components through solid, plate/shell or beam elements. Finite element analysis through 3-D solid elements is costly and may require time in weeks, which may not be at the disposal of an analyst. Axi-symmetric components and components with an infinite radius of curvature (flat surfaces), but with complex cross sections can be modeled by 2-D axi-symmetric and plate elements, respectively. Two dimensional finite elements require less time and hardware support than three-dimensional elements. Two development cases of successful application of 2-D finite elements instead of 3-D finite elements are discussed. Experimental and analytical verification of FEA results, and guidelines for checking finite element mesh discretization error are presented.
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Kumar, Ram, Deepak Kumar, and Bapon Paul. "Nonlinear Dynamic Analysis of 2-D Jacket Structure Considering Joint Nonlinearity." In ASME 2024 43rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2024. http://dx.doi.org/10.1115/omae2024-124560.
Full textAbstract:
Abstract Jacket structures are recognized for their fixed-base design and inherent structural stiffness among the most critical offshore engineering structures. This rigidity, stemming from their solid connection to the foundation, results in a slightly shorter natural time period than their floating structures. Comprising a framework of interconnected tubular members with rigid connections, jacket structures offer durability and stability in the challenging offshore environment. However, the operational performance of these jacket structures is significantly influenced by dynamic forces arising from the random ocean environment. The interaction between the random ocean dynamics and the structural integrity of jacket structures can lead to joint rotations and deformations, introducing nonlinearity into the system. The extent of joint nonlinearity is a critical factor that can intensely affect these offshore structures’ dynamic responses. This comprehensive study extends its focus to involve complete 2D jacket structures by using Finite Element Analysis (FEA) software ABAQUS to model joint behaviour and understand the details of nonlinear dynamic behaviour. The joint modeling approach not only considers the influence of varying angles between members but also accounts for joint level buckling under varying external loading conditions. In the presence of joint buckling, the nonlinear behaviour of the jacket structure changes significantly. This becomes more significant because it may cause significant fatigue damage to the structural joints. The study is focused on understanding the joint buckling and its nature under random ocean waves for a 2D jacket structure. Further, the effect of buckling on the nature of response is studied. This research enhances our understanding of the interaction between structural nonlinear elements (under joint buckling) and dynamic forces, ultimately offering essential information for offshore engineering design, assessment, and safety.
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Kim, Jihyeon, and Narakorn Srinil. "3-D Numerical Simulations of Subsea Jumper Transporting Intermittent Slug Flows." In ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/omae2018-77299.
Full textAbstract:
Subsea jumper is the steel pipe structure to connect wellhead and subsea facilities such as manifolds or processing units in order to transport the produced multiphase flows. Generally, the jumper consists of a goalpost with two loop structures and a straight pipe between them, carrying the multiphase oil and gas from the producing well. Due to the jumper pipe characteristic geometry and multi-fluid properties, slug flows may take place, creating problematic fluctuating forces causing the jumper oscillations. Severe dynamic fluctuations cause the risk of pipe deformations and resonances resulting from the hydrodynamic momentum/pressure forces which can lead to unstable operating pressure and decreased production rate. Despite the necessity to design subsea jumper with precise prediction on the process condition and the awareness of slug flow risks, it is challenging to experimentally evaluate, identify and improve the modified design in terms of the facility scale, time and cost efficiency. With increasing high computational performance, numerical analysis provides an alternative approach to simulate multiphase flow-induced force effects on the jumper. The present paper discusses the modelling of 3-D flow simulations in a subsea jumper for understanding the development process of internal slug flows causing hydrodynamic forces acting on the pipe walls and bends. Based on the fluctuating pressure calculated by the fluid solver, dynamic responses of the jumper pipe are assessed by a one-way interaction approach to evaluate deformation and stress. A potential resonance is discussed with the jumper modal analysis. Results from the structural response analyses show dominant multi-modal frequencies due to intermittent slug flow frequencies. Numerical results and observed behaviors may be useful for a comparison with other simulation and experiment.
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Sofla, Aarash Y. N., Dana M. Elzey, and Haydn N. G. Wadley. "An Antagonistic Flexural Unit Cell for Design of Shape Morphing Structures." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-62149.
Full textAbstract:
An antagonistic flexural unit cell (AFC) concept for the design and fabrication of novel 2-D and 3-D lightweight shape morphing structures is introduced. A fully reversible flexural shape changing cell utilizing opposing one-way shape memory alloy (SMA) actuators is shown to require no spring-like bias elements. The SMA actuating elements are arranged such that the actuation (contraction) of one of them stretches the other one in the cell, preparing it to be actuated later to reverse a flexural displacement. This antagonistic operation allows fully reversed cyclic operation. The focus of this paper is an assessment of performance at the single cell level. The cell logically provides four possible configurations in different stages of its cycle. Two of them are of particular interest because they provide two different fixed shapes for the cell that can be maintained without the continuous supply of external energy. The final deformations of the cell and equilibrium stresses in the SMA elements depend on the amount of stored shape memory strain in each element, external forces and cell geometry. A model is developed, which allows a full characterization of the AFC. The model is used to study NiTi SMA-based AFCs and the results are therefore directly applicable to the design of shape morphing structures using such unit cells.
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Kabova, Yu O., and O. A. Kabov. "Heater Size Effect on 3D Liquid Film Flow." In ASME 2007 5th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2007. http://dx.doi.org/10.1115/icnmm2007-30095.
Full textAbstract:
Thin liquid films may provide very high heat transfer intensity and may be used for cooling of microelectronic equipment. Investigation of the influence of size of hot spots on 3-D structures, occurring at the film surface, is the main objective of the present work. Calculations were carried out for a rectangular heater of different width. It was obtained that there is a heater size effect on 3D liquid film deformations. Film pattern changes in spanwise direction with the heater size. Calculations have been done for various liquid Reynolds numbers.
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Kabir, Mobashar, Tasneem Pervez, Farooq K. S. Al-Jahwari, and Sayyad Zahid Qamar. "Modeling of Human Femoral Bone Idealized As Functionally Graded and Laminated Composite Structure." In ASME 2023 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/imece2023-112920.
Full textAbstract:
Abstract Femur, the largest bone in the human skeletal system, provides critical mechanical support in bearing internal and external loads. It is a sophisticated natural composite with a complex hierarchical construction of multiple layers having varying material properties. This research work explores modeling approaches focusing on localized behavior of bone material under lateral loads. Small elements taken from cross-sections of femur bone are considered for analysis. To simplify the analysis, it is assumed that the chosen elements can be idealized as plate structures. Two representative bone models are presented and their structural response under similar loading and boundary conditions is investigated. In the laminated composite approach, an idealized bone plate is modelled as a layered composite of discrete orthotropic and isotropic layers with a stepped variation in material properties along the thickness. In the functionally graded approach, an identical representative plate is modelled as a functionally graded structure with a gradual change in properties instead. Material properties of femoral bone used in this work were acquired from experimental data available in literature. A higher order shear deformation theory with seven degrees of freedom is then used to obtain deformation and stresses using analytical and finite element methods. Accuracy of the models are validated by benchmarking with 3-D elasticity solutions and published reference data in literature. Preliminary results show generally lower deformations in the functionally graded model with smooth and continuous stress profiles.
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Stensrud, E., G. Hamre, G. Løvoll, et al. "Artificial Intelligence as a Means to Automate Detection of Defects in Inspection of Hull Structures." In Offshore Technology Conference. OTC, 2025. https://doi.org/10.4043/35708-ms.
Full textAbstract:
This paper reports on the status from further development from the outcome of an R&D project developing a digital twin of a physical asset. The asset in this case is a ship tank, and the digital twin is populated with both new and historic data representing the condition of the asset, such as video, point clouds from laser scans, and thickness measurements. The data are collected by autonomous drones equipped with video camera, LIDAR, and UT sensor. AI algorithms then "inspect" the data and detect anomalies such as corrosion, cracks, and deformations. Use of the automated drone improves safety by reducing the need for manned entry into confined spaces. Use of the AI-enabled analysis algorithms improves efficiency by automatically identifying and flagging potential defects for evaluation by a surveyor, thus obviating the need for human review of many hours of video footage. This paper is intended to be a follow-on to the work presented at OTC in May 2024, reference OTC-35308-MS ‘Risk-Based Inspections using Digital Twins for Hulls and Structures of Floating Assets’ (Stensrud et al. 2024). Thus, more extensive motivation and other background information are not repeated in this paper. The functionality in the digital twin includes semi-automated inspection planning, automated generation of the drone's flight plan from the inspection plan, automated and autonomous drone flight, and ML algorithms for automated detection of defects such as cracks, corrosion, coating damage, and deformations.
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Molinari, G., M. Quack, A. F. Arrieta, M. Morari, and P. Ermanni. "Design and Realization of a Compliant Adaptable Wing." In ASME 2014 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/smasis2014-7531.
Full textAbstract:
This paper presents the design, optimization, realization and testing of a novel wing morphing concept based on compliant structures actuated by Macro Fiber Composites. The geometry of the compliant morphing ribs is determined through multidisciplinary optimizations. The static and dynamic behavior of the wing, and the effect of activating the actuators, is assessed using 3-D aeroelastic simulations. The performance and manufacturability of a wing designed according to this approach are investigated. The achieved active deformations produce sufficient roll control authority to replace conventional ailerons. The numerical simulation for the conformal shape adaptation of the wing is compared to experimental results, showing good agreement. The aerodynamic and structural behavior of the introduced concept is investigated through a validated finite element model, revealing the potential of the presented morphing wing. A closed-loop controller driving high-voltage electronics counteracts the nonlinearity and hysteresis of the piezoelectric actuators, allowing for controlling the wings’ morphing level.
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Samadani, S., A. A. Aghakouchak, and J. Mirzadeh Niasar. "Nonlinear Analysis of Offshore Platforms Subjected to Earthquake Loading Considering the Effects of Joint Flexibility." In ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79851.
Full textAbstract:
In a conventional method of structural analysis, for modeling and analysis of jacket type offshore platforms, member connections are assumed to be rigid. In this method, members are rigidly connected which means there is no axial or rotational deformation at the end of brace member relative to chord axis. However in reality local deformations occur at chord surface due to applied loads from braces, which mean tubular joints are considerably flexible especially in non linear range of deformations. Therefore results of analysis based on rigid connections assumption differ from real behavior of the structure. Various research works have been carried out in the past on tubular joints and different methods have been presented in order to include the effect of joint flexibility in structural analysis. Most of these methods are just valid in elastic range but some non-linear methods have also been developed for simple tubular joints. In order to carry out a nonlinear analysis on a 3-D model of an offshore platform with multi-brace / multi-planar tubular joints, none of these simplified methods is applicable. In this case a complete model of tubular joints by non-linear shell elements is the most accurate one which is not only valid for non-linear analyses but also covers all type of tubular joints. In this paper two samples of offshore platforms are studied. These platforms are modeled using the following approaches: 1. No modeling of joints as structural elements (rigid connections). 2. Modeling of joint can with nonlinear shell elements (flexible connection). Different types of static non-linear analysis (Push over) are carried out and results are compared. In order to evaluate the results and compare this type of modeling with simplified methods included in professional software for the analysis of offshore structures, aforementioned platforms are also analyzed using the Fessler and MSL models to include effects of joint flexibility. The results of these types of modeling are also compared with the previous ones.