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Добірка наукової літератури з теми "Multi-Scale finite element method"

Автор: Grafiati

Опубліковано: 7 грудня 2024

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Статті в журналах з теми "Multi-Scale finite element method"

Li, Cui Yu, and Xiao Tao Zhang. "Multi-Scale Finite Element Method and its Application." Advanced Materials Research 146-147 (October 2010): 1583–86. http://dx.doi.org/10.4028/www.scientific.net/amr.146-147.1583.

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In order to improve the computing precision and computing efficiency of strength of woven composite material, the strength of woven composite material based on multi-scale finite element method (MsFEM) is simulated. The periodical boundary conditions are applied to the finite element method analyses to ensure stress continuous and strain continuous on boundary surfaces. The method can efficiently capture the large scale behavior of the solution without resolving all the small scale features by constructing the multi-scale finite element base functions that are adaptive to the local property of the differential operator. The characteristic difference between MsFEM and the conventional finite element method is attributed to base function. The applications demonstrate that the advantages of the multi-scale finite element method for numerical simulation of strength problem of woven composite material, i.e. significantly reducing computational efforts, and improving the accuracy of the solutions.

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Hiu, Haifeng, Changzhi Wang, and Xiaoguang Hu. "Multi-scale Finite Element Method for Members for Pipe Frames." IOP Conference Series: Earth and Environmental Science 446 (March 21, 2020): 052045. http://dx.doi.org/10.1088/1755-1315/446/5/052045.

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Chen, Ning, Jiaojiao Chen, Jian Liu, Dejie Yu, and Hui Yin. "A homogenization-based Chebyshev interval finite element method for periodical composite structural-acoustic systems with multi-scale interval parameters." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 10 (December 12, 2018): 3444–58. http://dx.doi.org/10.1177/0954406218819030.

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For the periodical composite structural-acoustic system with multi-scale interval uncertainties, a new interval analysis approach is presented in this study. In periodical composites structural-acoustic systems with multi-scale interval parameters, the variation ranges of the sound pressure response can be calculated using the homogenization-based interval finite element method. However, the homogenization-based interval finite element method that is based on Taylor series can only suit periodical composites structural-acoustic problems with small uncertainty degree. To consider larger uncertainty degree, by combining the Chebyshev polynomial series and the homogenization-based finite element, a homogenization-based Chebyshev interval finite element method is presented to predict the sound pressure responses of the structural-acoustic system involving periodical composite and multi-scale interval parameters. Compared with homogenization-based interval finite element method, homogenization-based Chebyshev interval finite element method can obtain higher accurate numerical solutions in the approximate process. Besides, homogenization-based Chebyshev interval finite element method can be implemented without conducting the complex derivation process. Numerical results verify the validity and practicability of the presented homogenization-based Chebyshev interval finite element method for the periodical composite structural-acoustic problem.

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Xiang, Jia Wei, Zhan Si Jiang, and Jin Yong Xu. "A Wavelet-Based Finite Element Method for Modal Analysis of Beams." Advanced Materials Research 97-101 (March 2010): 2728–31. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.2728.

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A new wavelet-based finite element method was proposed for analyzing modal parameters of beams. The Hermite cubic splines wavelet on the interval (HCSWI) was employed as the multi-scale interpolating basis for construct beam element. For the orthogonal characteristic of the wavelet basis with respect to given inner product, the corresponding multi-scale finite element equation will decoupled across scales totally or partially and suit for nesting approximation. Some numerical examples indicate that the proposed method have higher efficiency and precision.

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Peng, Mengyao, Min Liu, Shuitao Gu, and Shidong Nie. "Multiaxial Fatigue Analysis of Jacket-Type Offshore Wind Turbine Based on Multi-Scale Finite Element Model." Materials 16, no. 12 (June 14, 2023): 4383. http://dx.doi.org/10.3390/ma16124383.

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The fatigue damage of a local joint is the key factor accounting for the structural failure of a jacket-type offshore wind turbine. Meanwhile, the structure experiences a complex multiaxial stress state under wind and wave random loading. This paper aims to develop a multi-scale modeling method for a jacket-type offshore wind turbine, in which local joints of the jacket are modeled in a detail by using solid elements, and other components are modeled via the common beam element. Considering the multiaxial stress state of the local joint, multi-axial fatigue damage analysis based on the multiaxial S–N curve is performed using equivalent Mises and Lemaitre methods. The uniaxial fatigue damage data of the jacket model calculated using the multi-scale finite element model are compared with those of the conventional beam model. The results show that the tubular joint of jacket leg and brace connections can be modeled using the multi-scale method, since the uniaxial fatigue damage degree can reach a 15% difference. The comparison of uniaxial and multiaxial fatigue results obtained using the multi-scale finite element model shows that the difference can be about 15% larger. It is suggested that the multi-scale finite element model should be used for better accuracy in the multiaxial fatigue analysis of the jacket-type offshore wind turbine under wind and wave random loading.

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KIM, HYOUNG SEOP. "MULTI-SCALE FINITE ELEMENT SIMULATION OF SEVERE PLASTIC DEFORMATION." International Journal of Modern Physics B 23, no. 06n07 (March 20, 2009): 1621–26. http://dx.doi.org/10.1142/s0217979209061366.

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The technique of severe plastic deformation (SPD) enables one to produce metals and alloys with an ultrafine grain size of about 100 nm and less. As the mechanical properties of such ultrafine grained materials are governed by the plastic deformation during the SPD process, the understanding of the stress and strain development in a workpiece is very important for optimizing the SPD process design and for microstructural control. The objectives of this work is to present a constitutive model based on the dislocation density and dislocation cell evolution for large plastic strains as applied to equal channel angular pressing (ECAP). This paper briefly introduces the constitutive model and presents the results obtained with this model for ECAP by the finite element method.

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Jia, Hongxing, Shizhu Tian, Shuangjiang Li, Weiyi Wu, and Xinjiang Cai. "Seismic application of multi-scale finite element model for hybrid simulation." International Journal of Structural Integrity 9, no. 4 (August 13, 2018): 548–59. http://dx.doi.org/10.1108/ijsi-04-2017-0027.

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Purpose Hybrid simulation, which is a general technique for obtaining the seismic response of an entire structure, is an improvement of the traditional seismic test technique. In order to improve the analysis accuracy of the numerical substructure in hybrid simulation, the purpose of this paper is to propose an innovative hybrid simulation technique. The technique combines the multi-scale finite element (MFE) analysis method and hybrid simulation method with the objective of achieving the balance between the accuracy and efficiency for the numerical substructure simulation. Design/methodology/approach To achieve this goal, a hybrid simulation system is established based on the MTS servo control system to develop a hybrid analysis model using an MFE model. Moreover, in order to verify the efficiency of the technique, the hybrid simulation of a three-storey benchmark structure is conducted. In this simulation, a ductile column—represented by a half-scale scale specimen—is selected as the experimental element, meanwhile the rest of the frame is modelled as microscopic and macroscopic elements in the Abaqus software simultaneously. Finally, to demonstrate the stability and accuracy of the proposed technique, the seismic response of the target structure obtained via hybrid simulation using the MFE model is compared with that of the numerical simulation. Findings First, the use of the hybrid simulation with the MFE model yields results similar to those obtained by the fine finite element (FE) model using solid elements without adding excessive computing burden, thus advancing the application of the hybrid simulation in large complex structures. Moreover, the proposed hybrid simulation is found to be more versatile in structural seismic analysis than other techniques. Second, the hybrid simulation system developed in this paper can perform hybrid simulation with the MFE model as well as handle the integration and coupling of the experimental elements with the numerical substructure, which consists of the macro- and micro-level elements. Third, conducting the hybrid simulation by applying earthquake motion to simulate seismic structural behaviour is feasible by using Abaqus to model the numerical substructure and harmonise the boundary connections between three different scale elements. Research limitations/implications In terms of the implementation of the hybrid simulation with the MFE model, this work is helpful to advance the hybrid simulation method in the structural experiment field. Nevertheless, there is still a need to refine and enhance the current technique, especially when the hybrid simulation is used in real complex engineering structures, having numerous micro-level elements. A large number of these elements may render the relevant hybrid simulations unattainable because the time consumed in the numeral calculations can become excessive, making the testing of the loading system almost difficult to run smoothly. Practical implications The MFE model is implemented in hybrid simulation, enabling to overcome the problems related to the testing accuracy caused by the numerical substructure simplifications using only macro-level elements. Originality/value This paper is the first to recognise the advantage of the MFE analysis method in hybrid simulation and propose an innovative hybrid simulation technique, combining the MFE analysis method with hybrid simulation method to strike a delicate balance between the accuracy and efficiency of the numerical substructure simulation in hybrid simulation. With the help of the coordinated analysis of FEs at different scales, not only the accuracy and reliability of the overall seismic analysis of the structure is improved, but the computational cost can be restrained to ensure the efficiency of hybrid simulation.

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Bardi, Istvan, Kezhong Zhao, Rickard Petersson, John Silvestro, and Nancy Lambert. "Multi-domain multi-scale problems in high frequency finite element methods." COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 32, no. 5 (September 9, 2013): 1471–83. http://dx.doi.org/10.1108/compel-04-2013-0123.

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Gai, Wen Hai, R. Guo, and Jun Guo. "Molecular Dynamics Approach and its Application in the Analysis of Multi-Scale." Applied Mechanics and Materials 444-445 (October 2013): 1364–69. http://dx.doi.org/10.4028/www.scientific.net/amm.444-445.1364.

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Numerical simulation of the behavior of materials can be used as a versatile, efficient and low cost tool for developing an understanding of material behavior [. The numerical simulation methods include quantum mechanics, molecular dynamics, Voronoi cell finite element method and finite element method et al. These methods themselves are not sufficient for many fundamental problems in computational mechanics, and the deficiencies lead to the thrust of multiple-scale methods. The multi-scale method to model micro-scale systems by coupled continuum mechanics and molecular dynamics was introduced. This paper describes the basic methods of multi-scale and general simulation process of molecular dynamics was reviewed.

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HE, WEN-YU, and WEI-XIN REN. "ADAPTIVE TRIGONOMETRIC HERMITE WAVELET FINITE ELEMENT METHOD FOR STRUCTURAL ANALYSIS." International Journal of Structural Stability and Dynamics 13, no. 01 (February 2013): 1350007. http://dx.doi.org/10.1142/s0219455413500077.

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Owing to its good approximation characteristics of trigonometric functions and the multi-resolution local characteristics of wavelet, the trigonometric Hermite wavelet function is used as the element interpolation function. The corresponding trigonometric wavelet beam element is formulated based on the principle of minimum potential energy. As the order of wavelet can be enhanced easily and the multi-resolution can be achieved by the multi-scale of wavelet, the hierarchical and multi-resolution trigonometric wavelet beam element methods are proposed for the adaptive analysis. Numerical examples have demonstrated that the aforementioned two methods are effective in improving the computational accuracy. The trigonometric wavelet finite element method (WFEM) proposed herein provides an alternative approach for improving the computational accuracy, which can be tailored for the problem considered.

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Дисертації з теми "Multi-Scale finite element method"

Balazi, atchy nillama Loïc. "Multi-scale Finite Element Method for incompressible flows in heterogeneous media : Implementation and Convergence analysis." Electronic Thesis or Diss., Institut polytechnique de Paris, 2024. http://www.theses.fr/2024IPPAX053.

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Cette thèse porte sur l'application d'une méthode d'éléments finis multi-échelles (MsFEM) pour résoudre les écoulements incompressibles dans des milieux multi-échelles. En effet, la simulation de l'écoulement dans un milieu multi-échelle comportant de nombreux obstacles, tel que le cœur d'un réacteur nucléaire, est un défi de taille. Afin de capturer avec précision les échelles les plus fines de l'écoulement, il est nécessaire d'utiliser un maillage très fin. Cependant, cela conduit souvent à des simulations difficiles à réaliser en raison du manque de ressources informatiques. Pour remédier à cette limitation, cette thèse développe une MsFEM non-conforme enrichie pour résoudre les écoulements visqueux incompressibles dans des milieux hétérogènes, basée sur la méthode classique des éléments finis non conformes de Crouzeix--Raviart avec des fonctions de poids d'ordre élevé. La MsFEM utilise un maillage grossier sur lequel de nouvelles fonctions de base sont définies. Ces fonctions ne sont pas les fonctions de base polynomiales classiques des éléments finis, mais résolvent les équations de la mécanique des fluides sur les éléments du maillage grossier. Ces fonctions sont elles-mêmes approximées numériquement sur un maillage fin, en tenant compte de tous les détails géométriques, ce qui confère à cette méthode son aspect multi-échelle. Une étude théorique de la MsFEM proposée est menée aux niveaux continu et discret. Tout d'abord, le caractère bien posé des problèmes locaux discrets impliqués dans la MsFEM a été démontré à l'aide de nouvelles familles d'éléments finis. Pour ce faire, une nouvelle famille d'éléments finis non conformes en trois dimensions sur les tétraèdres a été développée. En outre, la première estimation d'erreur pour l'approximation du problème de Stokes dans des milieux perforés périodiques à l'aide de cette MSFEM est établie, démontrant sa convergence. Cette estimation est basée sur la théorie de l'homogénéisation du problème de Stokes dans les domaines périodiques et sur la théorie usuelle des éléments finis. Au niveau numérique, la MsFEM pour résoudre les problèmes de Stokes et d'Oseen en deux et trois dimensions a été implémenté dans un cadre massivement parallèle dans FreeFEM. En outre, une méthodologie pour résoudre le problème de Navier-Stokes est fournie
This thesis is concerned with the application of a Multi-scale Finite Element Method (MsFEM) to solve incompressible flow in multi-scale media. Indeed, simulating the flow in a multi-scale media with numerous obstacles, such as nuclear reactor cores, is a highly challenging endeavour. In order to accurately capture the finest scales of the flow, it is necessary to use a very fine mesh. However, this often leads to intractable simulations due to the lack of computational resources. To address this limitation, this thesis develops an enriched non-conforming MsFEM to solve viscous incompressible flows in heterogeneous media, based on the classical non-conforming Crouzeix--Raviart finite element method with high-order weighting functions. The MsFEM employs a coarse mesh on which new basis functions are defined. These functions are not the classical polynomial basis functions of finite elements, but rather solve fluid mechanics equations on the elements of the coarse mesh. These functions are themselves numerically approximated on a fine mesh, taking into account all the geometric details, which gives the multi-scale aspect of this method. A theoretical investigation of the proposed MsFEM is conducted at both the continuous and discrete levels. Firstly, the well-posedness of the discrete local problems involved in the MsFEM was demonstrated using new families of finite elements. To achieve this, a novel non-conforming finite element family in three dimensions on tetrahedra was developed. Furthermore, the first error estimate for the approximation of the Stokes problem in periodic perforated media using this MSFEM is derived, demonstrating its convergence. This is based on homogenization theory of the Stokes problem in periodic domains and on usual finite element theory. At the numerical level, the MsFEM to solve the Stokes and the Oseen problems in two and three dimensions is implemented in a massively parallel framework in FreeFEM. Furthermore, a methodology to solve the Navier–Stokes problem is provided

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Adzima, M. Fauzan. "Constitutive modelling and finite element simulation of martensitic transformation using a computational multi-scale framework." Thesis, Swansea University, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678581.

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HUI, YANCHUAN. "Multi-scale Modelling and Design of Composite Structures." Doctoral thesis, Politecnico di Torino, 2019. http://hdl.handle.net/11583/2739922.

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Bettinotti, Omar. "A weakly-intrusive multi-scale substitution method in explicit dynamics." Thesis, Cachan, Ecole normale supérieure, 2014. http://www.theses.fr/2014DENS0032/document.

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Анотація:

Les matériaux composites stratifiés sont de plus en plus utilisés dans l'aéronautique, mais ils peuvent être sujets à large délaminage si soumis à impact. La nécessité d'effectuer des simulations numériques pour prédire l’endommagement devient essentielle pour l’ingénieur. Dans ce contexte, l'utilisation d'une modélisation fine semble préférable. En revanche, le coût de calcul associé serait prohibitif pour larges structures. Le but de ce travail consiste à réduire ce coût de calcul, en couplant le modèle fin, restreint à la zone active de délaminage, avec un modèle grossier appliqué au reste de la structure. En raison du comportement transitoire des problèmes d'impact, l'adaptabilité dynamique des modèles pour suivre les phénomènes évolutifs représente un point crucial de la stratégie de couplage. Des méthodes avancées sont utilisées pour coupler différents modèles. Par exemple, la méthode de Décomposition de Domaines, appliquée à l'adaptabilité dynamique, doit être combinée avec une stratégie de remaillage, considérée comme intrusive pour la mise en œuvre d'un logiciel pour Analyse à Eléments Finis. Dans ce travail, les bases d'une approche faiblement intrusive, la méthode de Substitution, sont présentés dans le domaine de la dynamique explicite. Il s’agît d’une formulation globale-locale, conçue pour appliquer un modèle grossier sur tout le domaine pour obtenir une réponse globale: ce pré-calcul est ensuite corrigé itérativement par l'application du modèle raffiné appliqué seulement où nécessaire. La vérification de la méthode de Substitution en comparaison avec la méthode de Décomposition de Domaines est présentée
Composite laminates are increasingly employed in aeronautics, but can be prone to extensive delamination when submitted to impact loads. The need of performing virtual testing to predict delamination becomes essential for engineering workflows, in which the use of a fine modeling scheme appears nowadays to be the preferred one. The associated computational cost would be prohibitively high for large structures. The goal of this work consists in reducing such computational cost coupling the fine model, restricted to the surroundings of the delamination process zone, with a coarse one applied to the rest of the structure. Due to the transient behavior of impact problems, the dynamic adaptivity of the models to follow evolutive phenomena represents a crucial feature for the coupling. Many methodologies are currently used to couple multiple models, such as non-overlapping Domain Decomposition method, that, applied to dynamic adaptivity, has to be combined with a re-meshing strategy, considered as intrusive implementation within a Finite Element Analysis software. In this work, the bases of a weakly-intrusive approach, called Substitution method, are presented in the field of explicit dynamics. The method is based on a global-local formulation and is designed so that it is possible to make use of the pre-fixed coarse model the meshes the whole structure to obtain a global response: this pre-computation is then iteratively corrected considering the application of the refined model only where required, in the picture of an adaptive strategy. The verification of the Substitution method in comparison with the Domain Decomposition method is presented

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Zhou, Zhiqiang. "Multiple-Scale Numerical Analysis of Composites Based on Augmented Finite Element Method." Scholarly Repository, 2010. http://scholarlyrepository.miami.edu/oa_dissertations/75.

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Advanced composites are playing a rapidly increasing role in all fields of material and structural related engineering practices. Damage tolerance analysis must be a critical integral part of composite structural design. The predictive capabilities of existing models have met with limited success because they typically can not account for multiple damage evolution and their coupling. As a result, current composite design is heavily dependent upon lengthy and costly test programs and empirical design methods. There is an urgent need for efficient numerical tools that are capable of analyzing the progressive failure caused by nonlinearly coupled, multiple damage evolution in composite materials. Such numerical tools are a necessity in achieving virtual testing of composites and other heterogeneous materials. In this thesis, an advanced finite element method named augmented finite element method (A-FEM) has been developed. This method is capable of incorporating nonlinear cohesive damage descriptions for major damage modes observed in composite materials. It also allows for arbitrary nucleation and propagation of such cohesive damages upon satisfactory of prescribed initiation and propagation criterion. Major advantages of the A-FEM include: 1) arbitrary cohesive cracking without the need of remeshing; 2) full compatibility with existing FEM packages; and 3) easy inclusion of intra-element material heterogeneity. The numerical capabilities of the A-FEM have been demonstrated through direct comparisons between prediction results and experimental observations of typical composite tests including 3-point bending of unidirectional laminates, open-hole tension of quasi-isotropic laminates, and double-notched tension of orthogonal laminates. In all these tests, A-FEM can predict not only the qualitative damage patterns but also quantitatively the nonlinear stress-strain curves and other history-dependent results. The excellent numerical capability of A-FEM in accurately accounting for multiple cracking in composites enables the use of A-FEM as a multi-scale numerical platform for virtual testing of composites. This has been demonstrated by a series of representative volume element (RVE) analyses which explicitly considered microscopic matrix cracking and fiber matrix interface debonding. In these cases the A-FEM successfully predicted the cohesive failure descriptions which can be used for macroscopic composite failure analyses. At the sublaminate scale, the problem of a transverse tunneling crack and its induced local delamination has been studied in detail. Two major coupling modes, which depends on the mode-I to mode-II fracture toughness ratio and cohesive strength values, has been revealed and their implications in composite engineering has been fully discussed. Finally, future improvements to the A-FEM so that it can be more powerful in serving as a numerical platform for virtual testing of composites are discussed.

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De, Mier Torrecilla Monica. "Numerical simulation of multi-fluid flows with the Particle Finite Element Method." Doctoral thesis, Universitat Politècnica de Catalunya, 2010. http://hdl.handle.net/10803/6872.

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La presencia simultánea de múltiples fluidos con diferentes propiedades ocurre en numerosos problemas medioambientales, procesos industriales y situaciones de la vida diaria. Algunos ejemplos son la interacción fluido-combustible en la extracción mejorada de petróleo, mezcla de polímeros, emulsiones en productos alimentarios, formación de gotas de lluvia en nubes, inyección en motores de combustión o reactores de columna de burbujas. A pesar de que los flujos de multi-fluidos son muy frecuentes, todavía suponen un reto tanto desde el punto de vista teórico como computacional. En el caso de fluidos inmiscibles, la dinámica de la interfase entre fluidos juega un papel determinante. El éxito en la simulación de estos flujos dependerá de la capacidad del método numérico de modelar con precisión la interfase y los fenómenos que tienen lugar en ella.
En este trabajo nos hemos centrado en entender la principios físicos básicos de los multi-fluidos y las dificultades que aparecen en su simulación numérica. Hemos extendido el Particle Finite Element Method (PFEM) a problemas de varios fluidos diferentes con el objetivo de explotar el hecho de que los métodos lagrangianos son especialmente adecuados para el seguimiento de todo tipo de interfases. Hemos desarrollado un esquema numérico capaz de tratar grandes saltos en las propiedades físicas (densidad y viscosidad), de incluir la tensión superficial y de representar las discontinuidades de las variables del flujo. El esquema se basa en desacoplar las variables de posición de los nodos, velocidad y presión a través de la linearización de Picard y un método de segregación de la presión que tiene en cuenta las condiciones de interfase. La interfase se ha definido alineada con la malla móvil, de forma que se mantiene el salto de propiedades físicas sin suavizar a lo largo del tiempo. Además, los grados de libertad de la presión han sido duplicados en los nodos de interfase para representar la discontinuidad de esta variable debido a la tensión superficial y a la viscosidad variable, y la malla ha sido refinada cerca de la interfase para mejorar la precisión de la simulación. Hemos aplicado el esquema resultante a diversos problemas académicos y geológicos, como el sloshingde dos fluidos, extrusión de fluidos viscosos, ascensión y rotura de una burbuja dentro de una columna de líquido, mezcla de magmas y fuentes invertidas (negatively buoyant jet).
The simultaneous presence of multiple fluids with different properties in external or internal flows is found in daily life, environmental problems, and numerous industrial processes, among many other practical situations. Examples arefluid-fuel interaction in enhanced oil recovery, blending of polymers, emulsions in food manufacturing, rain droplet formation in clouds, fuel injection in engines, and bubble column reactors, to name only a few. Although multi-fluid flows occur frequently in nature and engineering practice, they still pose a major research challenge from both theoretical and computational points of view. In the case of immiscible fluids, the dynamics of the interface between fluids plays a dominant role. The success of the simulation of such flows will depend on the ability of the numerical method to model accurately the interface and the phenomena taking place on it.

In this work we have focused on understanding the basic physical principles of multi-fluid flows and the difficulties that arise in their numerical simulation. We have extended the Particle Finite Element Method to problems involving several different fluids with the aim of exploiting the fact that Lagrangian methods are specially well suited for tracking any kind of interfaces. We have developed a numerical scheme able to deal with large jumps in the physical properties, included surface tension, and able to accurately represent all types of discontinuities in the flow variables at the interface. The scheme is based on decoupling the nodes position, velocity and pressure variables through the Picard linearization and a pressure segregation method which takes into account the interface conditions. Theinterface has been defined to be aligned with the moving mesh, so that it remains sharp along time. Furthermore, pressure degrees of freedom have been duplicated at the interface nodes to represent the discontinuity of this variable due to surface tension and variable viscosity, and the mesh has been refined in the vicinity of the interface to improve the accuracy of the computations. We have applied the resulting scheme to several academic and geological problems, such as the two-fluid sloshing, extrusion of viscous fluids, bubble rise and break up, mixing of magmatic liquids and negatively buoyant jets.

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Zhao, Kezhong. "A domain decomposition method for solving electrically large electromagnetic problems." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1189694496.

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Kimn, Edward Sun. "A parametric finite element analysis study of a lab-scale electromagnetic launcher." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39498.

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The purpose of the study is to better understand the factors that affect melt-wear in the armature-to-rail contact interface of an electromagnetic launcher (EML). In order to investigate the factors, the study uses finite element analysis (FEA) to vary parameters of a lab-scale EML at the Georgia Institute of Technology. FEA is used due to the complex nature of the system, which includes the geometry and various engineering aspects that the EML incorporates. The study focuses on an uncoupled analysis of the structural, electromagnetic (EMAG), thermal, and modal aspects. The reason for the uncoupled analysis was because the system was complex and there were computational limits. Also, by uncoupling the analysis fields, the way the parameters affected melt-wear could be viewed separately. The study varied the geometry of the armature, the stiffness of the rail system (compliance layer), and the material of the armature. The structural analysis was for the initial contact of the rail to the armature and found the von Mises stresses, contact area, and contact pressure. The EMAG analysis found the Lorentz forces in the system based on a current curve used in the lab-scale EML. The thermal analysis consisted of friction heating and Joule heating. The modal analysis was for the unstressed and pre-stressed armature. Based on the study conducted, it was found that aluminum would provide the best speeds due to its lighter mass, but lacked in the thermal resistance area. Tungsten provided the better thermal resistance, but lacked in the potential speed due to its heavier mass.

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Guney, Murat Efe. "High-performance direct solution of finite element problems on multi-core processors." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34662.

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A direct solution procedure is proposed and developed which exploits the parallelism that exists in current symmetric multiprocessing (SMP) multi-core processors. Several algorithms are proposed and developed to improve the performance of the direct solution of FE problems. A high-performance sparse direct solver is developed which allows experimentation with the newly developed and existing algorithms. The performance of the algorithms is investigated using a large set of FE problems. Furthermore, operation count estimations are developed to further assess various algorithms. An out-of-core version of the solver is developed to reduce the memory requirements for the solution. I/O is performed asynchronously without blocking the thread that makes the I/O request. Asynchronous I/O allows overlapping factorization and triangular solution computations with I/O. The performance of the developed solver is demonstrated on a large number of test problems. A problem with nearly 10 million degree of freedoms is solved on a low price desktop computer using the out-of-core version of the direct solver. Furthermore, the developed solver usually outperforms a commonly used shared memory solver.

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Schiava, D'Albano Guillermo Gonzalo. "Computational and algorithmic solutions for large scale combined finite-discrete elements simulations." Thesis, Queen Mary, University of London, 2014. http://qmro.qmul.ac.uk/xmlui/handle/123456789/9071.

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In this PhD some key computational and algorithmic aspects of the Combined Finite Discrete Element Method (FDEM) are critically evaluated and either alternative novel or improved solutions have been proposed, developed and tested. In particular, two novel algorithms for contact detection have been developed. Also a comparative study of different contact detection algorithms has been made. The scope of this work also included large and grand scale FDEM problems that require intensive use of CPU; thus, novel parallelization solutions for grand scale FDEM problems have been developed and implemented using the MPI (Message Passing Interface) based domain decomposition. In this context a special attention is paid to the rapidly developing multi-core desktop architectures. The proposed novel solutions have been intensively validated and verified and demonstrated using various problems from literature.

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Книги з теми "Multi-Scale finite element method"

Habashi, W. G. Large-scale computational fluid dynamics by the finite element method. New York: American Institute of Aeronautics and Astronautics, 1991.

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E, Tezduyar T., and United States. National Aeronautics and Space Administration., eds. Finite element solution techniques for large-scale problems in computational fluid dynamics. [Washington, DC: National Aeronautics and Space Administration, 1987.

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L, Lin T., Povinelli Louis A, and United States. National Aeronautics and Space Administration., eds. Large-scale computation of incompressible viscous flow by least-squares finite element method. [Washington, DC: National Aeronautics and Space Administration, 1993.

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Center, Langley Research, ed. Analytic and computational perspectives of multi-scale theory for homogeneous, laminated composite, and sandwich beams and plates. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 2012.

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A, Saravanos D., and NASA Glenn Research Center, eds. A mixed multi-field finite element formulation for thermopiezoelectric composite shells. [Cleveland, Ohio]: National Aeronautics and Space Administration, Glenn Research Center, 1999.

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Shigemi, Masashi. Finite element analysis of incompressible viscous flows around single and multi-element aerofoils in high Reynolds number region. Tokyo: National Aerospace Laboratory, 1988.

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Tan, Cher Ming. Applications of finite element methods for reliability studies on ULSI interconnections. London: Springer, 2011.

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Частини книг з теми "Multi-Scale finite element method"

van Eekelen, Tom. "Radiation Modeling Using the Finite Element Method." In Solar Energy at Urban Scale, 237–57. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118562062.ch11.

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Andreev, A. B., J. T. Maximov, and M. R. Racheva. "Finite Element Method for Plates with Dynamic Loads." In Large-Scale Scientific Computing, 445–53. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/3-540-45346-6_47.

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Roters, Franz. "The Texture Component Crystal Plasticity Finite Element Method." In Continuum Scale Simulation of Engineering Materials, 561–72. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527603786.ch28.

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Iliev, Oleg P., Raytcho D. Lazarov, and Joerg Willems. "Discontinuous Galerkin Subgrid Finite Element Method for Heterogeneous Brinkman’s Equations." In Large-Scale Scientific Computing, 14–25. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-12535-5_2.

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Hofreither, Clemens, Ulrich Langer, and Clemens Pechstein. "A Non-standard Finite Element Method Based on Boundary Integral Operators." In Large-Scale Scientific Computing, 28–39. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-29843-1_3.

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Lazarov, Boyan S. "Topology Optimization Using Multiscale Finite Element Method for High-Contrast Media." In Large-Scale Scientific Computing, 339–46. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-43880-0_38.

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Matonoha, Ctirad, Alexej Moskovka, and Jan Valdman. "Minimization of p-Laplacian via the Finite Element Method in MATLAB." In Large-Scale Scientific Computing, 533–40. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-97549-4_61.

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Preußer, T., and M. Rumpf. "An Adaptive Finite Element Method for Large Scale Image Processing." In Scale-Space Theories in Computer Vision, 223–34. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/3-540-48236-9_20.

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Palha, Artur, and Marc Gerritsma. "Mimetic Least-Squares Spectral/hp Finite Element Method for the Poisson Equation." In Large-Scale Scientific Computing, 662–70. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-12535-5_79.

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Steinbach, Olaf, and Huidong Yang. "An Algebraic Multigrid Method for an Adaptive Space–Time Finite Element Discretization." In Large-Scale Scientific Computing, 66–73. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-73441-5_6.

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Тези доповідей конференцій з теми "Multi-Scale finite element method"

Li Zhang and Guizhen Lu. "Analysis of multi scale finite element method in low frequency." In 2014 IEEE Workshop on Advanced Research and Technology in Industry Applications (WARTIA). IEEE, 2014. http://dx.doi.org/10.1109/wartia.2014.6976414.

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Ma, Xinyu, Nana Duan, Weijie Xu, and Shuhong Wang. "Multi-Scale Finite Element Method Applied in 3D Nonlinear Problem." In 2024 IEEE 21st Biennial Conference on Electromagnetic Field Computation (CEFC). IEEE, 2024. http://dx.doi.org/10.1109/cefc61729.2024.10585808.

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LIU, WING. "Multi-scale finite element methods for structural dynamics." In 32nd Structures, Structural Dynamics, and Materials Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1991. http://dx.doi.org/10.2514/6.1991-1057.

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Dongdong, Zeng, Li Yanfei, and Lu Guizhen. "Study on multi-scale finite element method for EM wave equation." In 2010 International Workshop on Electromagnetics; Applications and Student Innovation (iWEM). IEEE, 2010. http://dx.doi.org/10.1109/aem2c.2010.5578775.

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Thompson, M. K. "Finite Element Modeling of Multi-Scale Thermal Contact Resistance." In ASME 2008 First International Conference on Micro/Nanoscale Heat Transfer. ASMEDC, 2008. http://dx.doi.org/10.1115/mnht2008-52385.

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Many traditional macro scale finite element models of thermal contact systems have incorporated the effect of micro scale surface topography by applying a constant value of thermal contact conductance (TCC) per unit area to the regions in contact. However, it has been very difficult to determine an appropriate TCC value for a given system and analysts typically had to rely on experimental data or values from the literature. This work presents a method for predicting micro scale TCC per unit area by incorporating micro scale surface roughness in a multi-scale iterative thermal/structural finite element contact model. The resulting TCC value is then used in a macro scale thermal/structural contact model with apparent surface form to predict the thermal contact resistance and overall thermal resistance for a commercial power electronics module.

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Cui-Yu Li and Xiao-Tao Zhang. "Numerical simulation of knitted fabric material with multi-scale finite element method." In 2009 International Conference on Machine Learning and Cybernetics (ICMLC). IEEE, 2009. http://dx.doi.org/10.1109/icmlc.2009.5212167.

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Manta, Asimina, Matthieu Gresil, and Constantinos Soutis. "MULTI-SCALE FINITE ELEMENT ANALYSIS OF GRAPHENE/POLYMER NANOCOMPOSITES ELECTRICAL PERFORMANCE." In VII European Congress on Computational Methods in Applied Sciences and Engineering. Athens: Institute of Structural Analysis and Antiseismic Research School of Civil Engineering National Technical University of Athens (NTUA) Greece, 2016. http://dx.doi.org/10.7712/100016.1936.7586.

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Cui-Yu Li and Xiao-Tao Zhang. "Numerical simulation of woven fabric material based on multi-scale finite element method." In 2008 International Conference on Machine Learning and Cybernetics (ICMLC). IEEE, 2008. http://dx.doi.org/10.1109/icmlc.2008.4620793.

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Tam, Nguyen Ngoc. "Multi-scale Sheet Metal Forming Analyses by using Dynamic Explicit Homogenized Finite Element Method." In NUMISHEET 2005: Proceedings of the 6th International Conference and Workshop on Numerical Simulation of 3D Sheet Metal Forming Process. AIP, 2005. http://dx.doi.org/10.1063/1.2011255.

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Yu, Qing, and Jer-Fang Wu. "Multi-Scale Finite Element Simulation of Progressive Damage in Composite Structures." In 25th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/omae2006-92064.

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A methodology for analyzing progressive damage accumulation on multiple spatial scales (micro- and macro-scale) in composite materials is presented in this paper. Idealization (homogenization) of heterogeneous media and evolution of damage on micro- and macro-scales are considered simultaneously at each incremental analysis step. The classical mathematical homogenization theory is extended to account for damage effects on distinct spatial scales through the introduction of an asymptotic expansion of damage parameter (or damage tensor in general). Local solutions on micro-scale provide the homogenized material properties that a global structure behaves on the macro-scales. The responses in the local fields, i.e. microscopic phases, can be reconstructed through the scale linking relations along with the global responses as input. The application of this multi-scale simulation method to composite patch repair for offshore structures is demonstrated by numerical examples.

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Звіти організацій з теми "Multi-Scale finite element method"

Shenoy, V. B., R. Miller, E. B. Tadmor, D. Rodney, and R. Phillips. An Adaptive Finite Element Approach to Atomic-Scale Mechanics: The Quasicontinuum Method. Fort Belvoir, VA: Defense Technical Information Center, November 1998. http://dx.doi.org/10.21236/ada358720.

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Zhu, Minjie, and Michael Scott. Two-Dimensional Debris-Fluid-Structure Interaction with the Particle Finite Element Method. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA, April 2024. http://dx.doi.org/10.55461/gsfh8371.

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In addition to tsunami wave loading, tsunami-driven debris can cause significant damage to coastal infrastructure and critical bridge lifelines. Using numerical simulations to predict loads imparted by debris on structures is necessary to supplement the limited number of physical experiments of in-water debris loading. To supplement SPH-FEM (Smoothed Particle Hydrodynamics-Finite Element Method) simulations described in a companion PEER report, fluid-structure-debris simulations using the Particle Finite Element Method (PFEM) show the debris modeling capabilities in OpenSees. A new contact element simulates solid to solid interaction with the PFEM. Two-dimensional simulations are compared to physical experiments conducted in the Oregon State University Large Wave Flume by other researchers and the formulations are extended to three-dimensional analysis. Computational times are reported to compare the PFEM simulations with other numerical methods of modeling fluid-structure interaction (FSI) with debris. The FSI and debris simulation capabilities complement the widely used structural and geotechnical earthquake simulation capabilities of OpenSees and establish the foundation for multi-hazard earthquake and tsunami simulation to include debris.

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Pask, J., N. Sukumar, M. Guney, and W. Hu. Partition-of-unity finite-element method for large scale quantum molecular dynamics on massively parallel computational platforms. Office of Scientific and Technical Information (OSTI), February 2011. http://dx.doi.org/10.2172/1021061.

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Zhang, Xingyu, Matteo Ciantia, Jonathan Knappett, and Anthony Leung. Micromechanical study of potential scale effects in small-scale modelling of sinker tree roots. University of Dundee, December 2021. http://dx.doi.org/10.20933/100001235.

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When testing an 1:N geotechnical structure in the centrifuge, it is desirable to choose a large scale factor (N) that can fit the small-scale model in a model container and avoid unwanted boundary effects, however, this in turn may cause scale effects when the structure is overscaled. This is more significant when it comes to small-scale modelling of sinker root-soil interaction, where root-particle size ratio is much lower. In this study the Distinct Element Method (DEM) is used to investigate this problem. The sinker root of a model root system under axial loading was analysed, with both upward and downward behaviour compared with the Finite Element Method (FEM), where the soil is modelled as a continuum in which case particle-size effects are not taken into consideration. Based on the scaling law, with the same prototype scale and particle size distribution, different scale factors/g-levels were applied to quantify effects of the ratio of root diameter (𝑑𝑟) to mean particle size (𝐷50) on the root rootsoil interaction.

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Terzic, Vesna, and William Pasco. Novel Method for Probabilistic Evaluation of the Post-Earthquake Functionality of a Bridge. Mineta Transportation Institute, April 2021. http://dx.doi.org/10.31979/mti.2021.1916.

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While modern overpass bridges are safe against collapse, their functionality will likely be compromised in case of design-level or beyond design-level earthquake, which may generate excessive residual displacements of the bridge deck. Presently, there is no validated, quantitative approach for estimating the operational level of the bridge after an earthquake due to the difficulty of accurately simulating residual displacements. This research develops a novel method for probabilistic evaluation of the post-earthquake functionality state of the bridge; the approach is founded on an explicit evaluation of bridge residual displacements and associated traffic capacity by considering realistic traffic load scenarios. This research proposes a high-fidelity finite-element model for bridge columns, developed and calibrated using existing experimental data from the shake table tests of a full-scale bridge column. This finite-element model of the bridge column is further expanded to enable evaluation of the axial load-carrying capacity of damaged columns, which is critical for an accurate evaluation of the traffic capacity of the bridge. Existing experimental data from the crushing tests on the columns with earthquake-induced damage support this phase of the finite-element model development. To properly evaluate the bridge's post-earthquake functionality state, realistic traffic loadings representative of different bridge conditions (e.g., immediate access, emergency traffic only, closed) are applied in the proposed model following an earthquake simulation. The traffic loadings in the finite-element model consider the distribution of the vehicles on the bridge causing the largest forces in the bridge columns.

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Guan, Jiajing, Sophia Bragdon, and Jay Clausen. Predicting soil moisture content using Physics-Informed Neural Networks (PINNs). Engineer Research and Development Center (U.S.), August 2024. http://dx.doi.org/10.21079/11681/48794.

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Environmental conditions such as the near-surface soil moisture content are valuable information in object detection problems. However, such information is generally unobtainable at the necessary scale without active sensing. Richards’ equation is a partial differential equation (PDE) that describes the infiltration process of unsaturated soil. Solving the Richards’ equation yields information about the volumetric soil moisture content, hydraulic conductivity, and capillary pressure head. However, Richards’ equation is difficult to approximate due to its nonlinearity. Numerical solvers such as finite difference method (FDM) and finite element method (FEM) are conventional in approximating solutions to Richards’ equation. But such numerical solvers are time-consuming when used in real-time. Physics-informed neural networks (PINNs) are neural networks relying on physical equations in approximating solutions. Once trained, these networks can output approximations in a speedy manner. Thus, PINNs have attracted massive attention in the numerical PDE community. This project aims to apply PINNs to the Richards’ equation to predict underground soil moisture content under known precipitation data.

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Turner, Andrew. Effect of Coupling on A-Walls for Slope Stabilization. Deep Foundations Institute, June 2018. http://dx.doi.org/10.37308/cpf-2015-land-1.

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A-Walls are retaining structures composed of at least two rows of regularly spaced deep foundation elements battered in opposing directions and connected through a grade beam to mitigate movements of a slope or embankment on soft soils. While A-Walls are commonly constructed using micropiles, they can be constructed using any type of deep foundation element. For example, Gómez, et al. ( 2013) described the use of a large A-Wall for mitigation of lateral movements of the North Plaza of the Jefferson Memorial in Washington, D.C. The lateral movements accompanied settlement of the edge of the fill under the North Plaza and had caused significant disturbance to the original seawall. The A-Wall consisted of drilled shafts and driven piles extending to depths greater than 100 ft and connected through the new, replacement reinforced concrete seawall, as depicted in Figure 1. A-Walls have been successfully used for slope stabilization using schemes similar to that shown in Figure 2 (Gómez et al., 2013). Loehr and Brown (2008) describe a method for predicting resisting forces in A-Walls for slope stabilization based on measurements from full-scale field installations of A-Walls and physical model tests involving scaled micropile elements. The method was a significant development because it appropriately accounts for the complex interaction between deep foundations and moving soils. Although the method satisfies displacement compatibility, it does so with uncoupled analyses involving separate lateral and axial analyses, without consideration of interaction between upslope and downslope piles (which are connected through a capping beam). This assumption may produce errors in predictions of reinforcement forces, and could have a notable effect on the predicted performance of A-Wall systems. To evaluate the effect of coupling, the research team analyzed slopes stabilized with A-Walls using a finite element model with upslope and downslope piles connected at the pile head. Results of the finite element analyses were compared to those of uncoupled lateral and axial analyses utilizing the p-y and t-z methods. Load-transfer parameters for the analyses were calibrated to data from field installations of A-Walls to demonstrate viability of the revised methodology. Results of the coupled analyses were then compared to results from Loehr and Brown (2008) to evaluate the effect of interaction between upslope and downslope piles. This report includes design implications resulting from the coupling effect and recommendations for further research.

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Zhu, Xian-Kui, and Bruce Wiersma. PR-644-213803-R01 Fatigue Life Models for Pipeline Containing Dents and Gouges. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), December 2022. http://dx.doi.org/10.55274/r0012248.

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Fatigue failure is a time-delayed failure that is one of the major threats to the pipeline integrity. For crack-like gouges in dents, the crack grows due to pressure cycling and eventually fails by fatigue. This work, which was funded by PRCI via Project MD-4-16, developed a viable engineering approach and a pragmatic fatigue model for predicting fatigue life of dents and gouges in pipelines. In particular, an equivalent stress method was developed with use of finite element analysis (FEA), and the crack driving force was determined based on the FEA results and the stress intensity factors (SIF) from API 579. The proposed fatigue model was evaluated with full-scale fatigue test data for line pipes containing dents and gouges, and then refined. The results showed that the refined fatigue model can predict adequate fatigue lives of dents and gouges in pipelines due to cyclic pressure. This report has a corresponding webinar.

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Bao, Jieyi, Xiaoqiang Hu, Cheng Peng, Junyi Duan, Yizhou Lin, Chengcheng Tao, Yi Jiang, and Shuo Li. Advancing INDOT’s Friction Test Program for Seamless Coverage of System: Pavement Markings, Typical Aggregates, Color Surface Treatment, and Horizontal Curves. Purdue University, 2024. http://dx.doi.org/10.5703/1288284317734.

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Various highway projects, roadway safety, and maintenance all hinge on pavement friction. INDOT's pavement friction test program has played a crucial role in addressing issues like wet pavement crash reduction, durable pavements surface friction, and sustainable aggregates. However, changes in the transportation sector, allied industries, societal needs, and economics present unique challenges that require proactive solutions. First, the existing field friction testing method, which uses a locked wheel skid tester (LWST) is limited to straight, flat pavement sections and excludes crash-prone areas like horizontal curves. Upgrading the program to cover horizontal curves on two-lane rural highways is vital for road safety. Second, the demand for friction testing on pavement markings at crash sites is rising. There's currently no widely accepted standard method for national-scale pavement marking friction testing. The shift to wider longitudinal pavement markings, from 4" to 6", driven by both human and autonomous vehicle safety, presents challenges for motorcyclists and pedestrians. The third challenge focuses on Color Surface Treatment (CST), which is increasingly used in Indiana bus and bike lanes for visibility, lane discipline, and friction performance, especially under frequent bus acceleration and braking. However, a lack of laboratory and field data necessitates investigating CST's metrics and requirements for adequate friction. Advancing INDOT's friction testing program to cover the entire highway system and address emerging friction challenges is imperative. The goals of this study included enhancing INDOT's friction testing, ensuring comprehensive highway network coverage and providing reliable friction data to help INDOT address safety concerns. The research encompassed a thorough evaluation of various aggregates and pavement marking materials commonly used in Indiana through laboratory experiments, field tests, and data analysis to unveil their influence on pavement friction. Field friction measurements on colored bus and bike lanes were also conducted and thoroughly analyzed. Moreover, the tire-pavement interaction on horizontal curves was assessed on airport runways and highway sections through mechanistic-empirical analysis, and a friction testing model for horizontal curves was devised using finite element analysis and machine learning methodologies.

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Chauhan and Wood. L52007 Experimental Validation of Methods for Assessing Closely Spaced Corrosion Defects. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), March 2005. http://dx.doi.org/10.55274/r0011167.

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A full-scale burst test program was devised and agreed with the PRCI Materials Technical Committee Ad Hoc group. The work was undertaken over a two year period, 2003 and 2004. Due to budget constraints, only one pipe diameter and material was chosen for the test program. This was 24� (610 mm) outside diameter (OD) by 7.9 mm wall thickness, welded ERW steel linepipe of material API 5L grade B/X42. The criterion that defects separated by a distance of 6t or less will interact is over conservative. New rules for interaction, derived using non-linear finite element analyses and validated using full scale burst testing, have been derived for closely spaced metal loss interacting defects in pipelines. New, robust interaction rules for assessing corrosion metal loss defects in pipelines have been formulated for use by the pipeline industry.

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