Relevant bibliographies by topics / FDM method

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
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Academic literature on the topic 'FDM method'

Author: Grafiati
Published: 28 June 2021
Last updated: 27 April 2022

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Journal articles on the topic "FDM method"

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Liu, Renwei, Dongjie Wang, Xinyu Zhang, Wang Li, and Bo Yu. "Comparison Study on the Performances of Finite Volume Method and Finite Difference Method." Journal of Applied Mathematics 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/596218.

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Vorticity-stream function method and MAC algorithm are adopted to systemically compare the finite volume method (FVM) and finite difference method (FDM) in this paper. Two typical problems—lid-driven flow and natural convection flow in a square cavity—are taken as examples to compare and analyze the calculation performances of FVM and FDM with variant mesh densities, discrete forms, and treatments of boundary condition. It is indicated that FVM is superior to FDM from the perspective of accuracy, stability of convection term, robustness, and calculation efficiency. Particularly ,when the mesh is coarse and taken as20×20, the results of FDM suffer severe oscillation and even lose physical meaning.
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Czyz, Marcin, Hesham Radwan, Jian Y. Li, Christopher G. Filippi, Tomasz Tykocki, and Michael Schulder. "Fractal Analysis May Improve the Preoperative Identification of Atypical Meningiomas." Neurosurgery 80, no. 2 (December 7, 2016): 300–308. http://dx.doi.org/10.1093/neuros/nyw030.

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Abstract BACKGROUND: There is no objective and readily accessible method for the preoperative determination of atypical characteristics of a meningioma grade. OBJECTIVE: To evaluate the feasibility of using fractal analysis as an adjunctive tool to conventional radiological techniques in visualizing histopathological features of meningiomas. METHODS: A group of 27 patients diagnosed with atypical (WHO grade II) meningioma and a second group of 27 patients with benign (WHO grade I) meningioma were enrolled in the study. Preoperative brain magnetic resonance (MR) studies (T1-wieghted, post-gadolinium) were processed and analyzed to determine the average fractal dimension (FDa) and maximum fractal dimension (FDm) of the contrast-enhancing region of the tumor using box-count method. FDa and FDm as well as particular radiological features were included in the logistic regression model as possible predictors of malignancy. RESULTS: The cohort consisted of 34 women and 20 men, mean age of 62 ± 15 yr. Fractal analysis showed good interobserver reproducibility (Kappa >0.70). Both FDa and FDm were significantly higher in the atypical compared to the benign meningioma group (P < .0001). Multivariate logistic regression model reached statistical significance with P = .0001 and AUC = 0.87. The FDm, which was greater than 1.31 (odds ratio [OR], 12.30; P = .039), and nonskull base localization (OR, .052; P = .015) were confirmed to be statistically significant predictors of the atypical phenotype. CONCLUSION: Fractal analysis of preoperative MR images appears to be a feasible adjunctive diagnostic tool in identifying meningiomas with potentially aggressive clinical behavior.
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Bommaraju, C., R. Marklein, and P. K. Chinta. "Optimally Accurate Second-Order Time-Domain Finite-Difference Scheme for Acoustic, Electromagnetic, and Elastic Wave Modeling." Advances in Radio Science 3 (May 12, 2005): 175–81. http://dx.doi.org/10.5194/ars-3-175-2005.

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Abstract. Numerical methods are extremely useful in solving real-life problems with complex materials and geometries. However, numerical methods in the time domain suffer from artificial numerical dispersion. Standard numerical techniques which are second-order in space and time, like the conventional Finite Difference 3-point (FD3) method, Finite-Difference Time-Domain (FDTD) method, and Finite Integration Technique (FIT) provide estimates of the error of discretized numerical operators rather than the error of the numerical solutions computed using these operators. Here optimally accurate time-domain FD operators which are second-order in time as well as in space are derived. Optimal accuracy means the greatest attainable accuracy for a particular type of scheme, e.g., second-order FD, for some particular grid spacing. The modified operators lead to an implicit scheme. Using the first order Born approximation, this implicit scheme is transformed into a two step explicit scheme, namely predictor-corrector scheme. The stability condition (maximum time step for a given spatial grid interval) for the various modified schemes is roughly equal to that for the corresponding conventional scheme. The modified FD scheme (FDM) attains reduction of numerical dispersion almost by a factor of 40 in 1-D case, compared to the FD3, FDTD, and FIT. The CPU time for the FDM scheme is twice of that required by the FD3 method. The simulated synthetic data for a 2-D P-SV (elastodynamics) problem computed using the modified scheme are 30 times more accurate than synthetics computed using a conventional scheme, at a cost of only 3.5 times as much CPU time. The FDM is of particular interest in the modeling of large scale (spatial dimension is more or equal to one thousand wave lengths or observation time interval is very high compared to reference time step) wave propagation and scattering problems, for instance, in ultrasonic antenna and synthetic scattering data modeling for Non-Destructive Testing (NDT) applications, where other standard numerical methods fail due to numerical dispersion effects. The possibility of extending this method to staggered grid approach is also discussed. The numerical FD3, FDTD, FIT, and FDM results are compared against analytical solutions.
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Long, Jingjunjiao, Hamideh Gholizadeh, Jun Lu, Craig Bunt, and Ali Seyfoddin. "Application of Fused Deposition Modelling (FDM) Method of 3D Printing in Drug Delivery." Current Pharmaceutical Design 23, no. 3 (February 20, 2017): 433–39. http://dx.doi.org/10.2174/1381612822666161026162707.

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Three-dimensional (3D) printing is an emerging manufacturing technology for biomedical and pharmaceutical applications. Fused deposition modelling (FDM) is a low cost extrusion-based 3D printing technique that can deposit materials layer-by-layer to create solid geometries. This review article aims to provide an overview of FDM based 3D printing application in developing new drug delivery systems. The principle methodology, suitable polymers and important parameters in FDM technology and its applications in fabrication of personalised tablets and drug delivery devices are discussed in this review. FDM based 3D printing is a novel and versatile manufacturing technique for creating customised drug delivery devices that contain accurate dose of medicine( s) and provide controlled drug released profiles.
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Gupta, Dr A. R. "Comparative analysis of Rectangular Plate by Finite element method and Finite Difference Method." International Journal for Research in Applied Science and Engineering Technology 9, no. 9 (September 30, 2021): 1397–98. http://dx.doi.org/10.22214/ijraset.2021.38152.

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Abstract: Plates are commonly used to support lateral or vertical loads. Before the design of such a plate, analysis is performed to check the stability of plate for the proposed load. There are several methods for this analysis. In this research, a comparative analysis of rectangular plate is done between Finite Element Method (FEM) and Finite Difference Method (FDM). The plate is considered to be subjected to an arbitrary transverse uniformly distributed loading and is considered to be clamped at the two opposite edges and free at the other two edges. The Finite Element Method (FEM) is a numerical technique for finding approximate solutions to boundary value problems for partial differential equations. It is also referred to as finite element analysis (FEA). FEM subdivides a large problem into smaller, simpler, parts, called finite elements. The work covers the determination of displacement components at different points of the plate and checking the result by software (STAAD.Pro) analysis. The ordinary Finite Difference Method (FDM) is used to solve the governing differential equation of the plate deflection. The proposed methods can be easily programmed to readily apply on a plate problem. Keywords: Arbitrary, FEM, FDM, boundary.
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Gębura, Andrzej, Jerzy Borowski, Bogdan Pietnoczko, Jan Darowski, Mieczysław Pigłas, and Ewelina Siekierska. "Analysis of measuring apparatus errors using the FAM-C and FDM-A methods." Journal of KONBiN 50, no. 4 (December 1, 2020): 217–36. http://dx.doi.org/10.2478/jok-2020-0083.

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Abstract The article discusses the errors of the electronic measuring apparatus built at AFIT using the FAM-C and FDM-A methods, dedicated to monitoring the technical condition of aircraft power units. The basic components and variants of the use of the built electronic apparatus are presented: the optimization of the selection of construction parameters and the change of the error level in the selection of various types of construction of a given system. The influence of external factors on errors of the measuring system was also described, including changes in the amplitude of the electrical power generator output signal and the influence of the carrier frequency depending on the phase configuration of the measuring system. The method of comprehensive checking of electronic measuring equipment for FAM-C and FDM-A methods in laboratory conditions was presented.
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Singh, Pushpendra, Shiv Dutt Joshi, Rakesh Kumar Patney, and Kaushik Saha. "The Fourier decomposition method for nonlinear and non-stationary time series analysis." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 473, no. 2199 (March 2017): 20160871. http://dx.doi.org/10.1098/rspa.2016.0871.

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for many decades, there has been a general perception in the literature that Fourier methods are not suitable for the analysis of nonlinear and non-stationary data. In this paper, we propose a novel and adaptive Fourier decomposition method (FDM), based on the Fourier theory, and demonstrate its efficacy for the analysis of nonlinear and non-stationary time series. The proposed FDM decomposes any data into a small number of ‘Fourier intrinsic band functions’ (FIBFs). The FDM presents a generalized Fourier expansion with variable amplitudes and variable frequencies of a time series by the Fourier method itself. We propose an idea of zero-phase filter bank-based multivariate FDM (MFDM), for the analysis of multivariate nonlinear and non-stationary time series, using the FDM. We also present an algorithm to obtain cut-off frequencies for MFDM. The proposed MFDM generates a finite number of band-limited multivariate FIBFs (MFIBFs). The MFDM preserves some intrinsic physical properties of the multivariate data, such as scale alignment, trend and instantaneous frequency. The proposed methods provide a time–frequency–energy (TFE) distribution that reveals the intrinsic structure of a data. Numerical computations and simulations have been carried out and comparison is made with the empirical mode decomposition algorithms.
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Lee, Chaeyoung, Jisang Lyu, Eunchae Park, Wonjin Lee, Sangkwon Kim, Darae Jeong, and Junseok Kim. "Super-Fast Computation for the Three-Asset Equity-Linked Securities Using the Finite Difference Method." Mathematics 8, no. 3 (February 26, 2020): 307. http://dx.doi.org/10.3390/math8030307.

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In this article, we propose a super-fast computational algorithm for three-asset equity-linked securities (ELS) using the finite difference method (FDM). ELS is a very popular investment product in South Korea. There are one-, two-, and three-asset ELS. The three-asset ELS is the most popular financial product among them. FDM has been used for pricing the one- and two-asset ELS because it is accurate. However, the three-asset ELS is still priced using the Monte Carlo simulation (MCS) due to the curse of dimensionality for FDM. To overcome the limitation of dimension for FDM, we propose a systematic non-uniform grid with an explicit Euler scheme and an optimal implementation of the algorithm. The computational time is less than 6 s. We perform standard ELS option pricing and compare the results from the fast FDM with the ones from MCS. The computational results confirm the superiority and practicality of the proposed algorithm.
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Novakova-Marcincinova, Ludmila, and Jozef Novak-Marcincin. "Testing of ABS Material Tensile Strength for Fused Deposition Modeling Rapid Prototyping Method." Advanced Materials Research 912-914 (April 2014): 370–73. http://dx.doi.org/10.4028/www.scientific.net/amr.912-914.370.

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In paper are presented information about materials used for production of models by Fused Deposition Modeling (FDM) rapid prototyping technology. In today's rapid prototyping technologies the initial state of building material can be in solid, liquid or powder state. The current range materials include plastic, nylon, wax, resins, metals and ceramics. In FDM are mainly used as basic materials ABS - Acrylonitrile Butadiene Styrene, polyamide, polycarbonate, polyethylene and polypropylene. Main part of the paper is focused on experimental testing of Acrylonitrile Butadiene Styrene materials realized by different research teams and presents outputs of testing of ABS material in FDM technology realized by authors.
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Başhan, Ali. "A mixed methods approach to Schrödinger equation: Finite difference method and quartic B-spline based differential quadrature method." An International Journal of Optimization and Control: Theories & Applications (IJOCTA) 9, no. 2 (July 31, 2019): 223–35. http://dx.doi.org/10.11121/ijocta.01.2019.00709.

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The present manuscript include, finite difference method and quartic B-spline based differential quadrature method (FDM-DQM) to obtain the numerical solutions for the nonlinear Schr¨odinger (NLS) equation. For this purpose, firstly Schrödinger equation has been converted into coupled real value differential equations and then they have been discretized using special type of classical finite difference method namely, Crank-Nicolson scheme. After that, Rubin and Graves linearization techniques have been utilized and differential quadrature method has been applied. So, partial differential equation turn into algebraic equation system. Next, in order to be able to test the accuracy of the newly hybrid method, the error norms L2 and L? as well as the two lowest invariants I1 and I2 have been calculated. Besides those, the relative changes in those invariants have been given. Finally, the newly obtained numerical results have been compared with some of those available in the literature for similar parameters. This comparison has clearly indicated that the currently utilized method, namely FDM-DQM, is an effective and efficient numerical schemeand allowed us to propose to solve a wide range of nonlinear equations.
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Dissertations / Theses on the topic "FDM method"

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Quan, Liang. "Using FDM and FEM to simulate the decarburization in AISI 1074 during heat processing and its impact." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/44769.

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The metallurgical processes and the products developed from these processes have been the cornerstone on which our civilizations have developed and flourished. Many of the new materials that have been developed over centuries were often the result of serendipitous occurrences. Because of the importance of new materials to the improvement of society, it is necessary to accelerate the way in which new alloys and processes are designed, developed and implemented. Over the last two decades the computational side of materials science has thrived as a result of bigger and faster computers. However, the application of new computational methods to the development of new materials and structures is still in the early stages primarily because of the complexity of most metallurgical processes. One such process is the decarburization of steel. Because of the importance of the microstructure on the mechanical properties, changes in the near surface properties are affected by the loss of carbon in the alloy. The topics investigated in this thesis include a variety of alloys and microstructures that are considered to be important in the development of a unique structure necessary for a more efficient method of recovering natural gas and oil from underground reserves as well as structures for energy absorbing systems. Since both the material application and the structure are new, this research represents an ideal opportunity to combine processing, properties, microstructure and computations to accelerate the development of these new structures. Compared to other commercially available proppants which tend to fail in demanding environments, the thin-walled hollow metal proppants are regarded more promising due to the low density and high mechanical strength. The energy-absorbing composite material manufactured by embedding said spheres in the Mg/Al matrix material is optimized by improving sphere and matrix properties at each step in the process. Ultimately the mechanical strength, fracture toughness, and energy absorption are expected to achieve a factor of 2-5 higher than previously reported. Modeling makes it economically practical to assess the targeted materials' overall properties, behaviors and the mechanical responses in conjunction with stress environment, material properties, material dimensions among other variables, before a structure is built. Additionally, more advanced modeling can enable the quantitative descriptions of more complex metallurgical phenomena such as the effects of impurity elements and deformation under complex loading conditions.
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Sayar, Sepideh. "Heat Transfer During Melting and Solidification in Heterogeneous Materials." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/36147.

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A one-dimensional model of a heterogeneous material consisting of a matrix with embedded separated particles is considered, and the melting or solidification of the particles is investigated. The matrix is in imperfect contact with the particles, and the lumped capacity approximation applies to each individual particle. Heat is generated inside the particles or is transferred from the matrix to the particles coupled through a contact conductance. The matrix is not allowed to change phase and energy is either generated inside the matrix or transferred from the boundaries, which is initially conducted through the matrix material. The physical model of this coupled, two-step heat transfer process is solved using the energy method. The investigation is conducted in several phases using a building block approach. First, a lumped capacity system during phase transition is studied, then a one-dimensional homogeneous material during phase change is investigated, and finally the one-dimensional heterogeneous material is analyzed. A numerical solution based on the finite difference method is used to solve the model equations. This method allows for any kind of boundary conditions, any combination of material properties, particle sizes and contact conductance. In addition, computer programs, using Mathematica, are developed for the lumped capacity system, homogeneous material, and heterogeneous material. Results show the effects of control volume thickness, time step, contact conductance, material properties, internal sources, and external sources.
Master of Science
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NOVOA, DANNY MESIAS CHAVEZ. "PHYSICAL -CHEMICAL EVALUATION OF HIGH DENSITY POLYETHYLENE PROCESSED BY THE 3D PRINTING METHOD OF FUSED DEPOSITION MODELING FDM." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2014. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=24466@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
O objetivo deste trabalho foi estudar a influencia das condições da impressão 3D nas propriedades finais do polietileno de alta densidade usando a modelagem por fusão e deposição, FDM. Foram impressos protótipos com formato de corpos de prova para teste de tração tipo V segundo norma ASTM D638, a três temperaturas de processamento: 220, 240 e 260 Graus Celsius. Para a impressão das amostras foram mantidos constantes os parâmetros de controle, entre eles a espessura da camada de impressão. As amostras impressas foram caracterizadas por difração de raios X, espectroscopia infravermelha, calorimetria diferencial de varredura, análise termogravimétrica, ensaio de tração, índice de fluidez e teste de contração. Os resultados das caracterizações das amostras impressas foram comparados com os resultados do material sem processar, cujas propriedades foram obtidas usando os mesmo métodos de caracterização. Estes resultados demostraram que as condições de impressão por FDM empregadas neste trabalho causaram apenas uma leve mudança nas características estruturais das amostras processadas do PEAD em relação ao material original sem processamento. Houve um leve aumento da cristalinidade no PEAD impresso (em torno de 1,3 a 3 porcento). Além disso, foi comprovado que por causa do resfriamento desigual na superfície e no interior da amostra impressa, o grau de cristalinidade foi levemente maior no interior que na superfície do corpo de prova impresso. A leve mudança no grau de cristalinidade não foi suficiente para causar mudança no módulo de elasticidade e no limite de escoamento em relação ao PEAD original. Outros resultados demostraram que não houve mudança significativa envolvendo formação de ligações duplas, quebra de cadeias e degradação térmica por efeito da condição do processamento utilizada durante a impressão.
The aim of this work was to study the influence of process conditions for 3D printing on the final properties of prototypes of high density polyethylene (HDPE) using the method of the fused deposition modeling. Prototypes for type-V tensile testing according to ASTM D 638 were printed; They were made to three processing temperatures: 220, 240 and 260 Celsius degree. Control parameters for printing were kept constant in all the samples. The printed samples were characterized by X – ray diffraction, infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, tensile test, melt flow index test, and, shrinkage test. The results of the characterization of the printed samples and of the original material were compared. These results demonstrated that the printing conditions employed in this study caused a slight change in the structural characteristics of the printed samples compared to the unprocessed original material, there being a slight increase in crystallinity (about 1,3 to 3 percent) for HDPE which was printed. In addition, it has been proven that the degree of crystallinity was slightly greater on the inside that on the surface of the printed samples, because of uneven cooling on the surface and inside of these samples. The slight change in the degree of crystallinity was not enough to cause change in the elastic modulus and yield strength compared to the original HDPE. Other results showed that there was not significant change involving bond formation, break chains, and, thermal degradation by the effect of the processing conditions used during printing.
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Almeida, Wagner José de. "Otimização estrutural de protótipos fabricados pela tecnologia FDM utilizando o método dos elementos finitos." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/18/18146/tde-05022010-163333/.

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Este trabalho tem como objetivo principal a otimização dos protótipos fabricados pelo processo FDM (Fused Deposition Modeling) em procedimento baseado na análise do comportamento estrutural dos protótipos variando as estratégias de preenchimento das camadas. Para atingir tal objetivo, corpos de prova com diferentes orientações de preenchimento foram ensaiados experimentalmente e os resultados foram verificados em análise estrutural por elementos finitos. Foram verificados o caráter ortotrópico do material do protótipo e a validade do uso da Teoria Clássica dos Laminados na simulação de seu comportamento. Os conceitos e metodologia de análise foram validados em estudos de casos, mostrando a viabilidade de sua aplicação na obtenção de protótipos funcionais
The objective of this work is to develop an optimization procedure for FDM prototypes. This procedure is based on the structural analysis of the prototypes within different slice filling paths. In order to reach this objective, experimental tests with different filling trajectories are conducted and the results are used in structural analysis by finite element method. The orthotropic behavior of the prototype material and the use of the Classical Laminate Theory in the numerical simulation were validated. The results were applied in different case studies, showing the viability of its application in the design of functional prototypes.
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Moraes, Tiago Bueno de. "O método da diagonalização filtrada (FDM) e suas aplicações para a Ressonância Magnética." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-16092011-084245/.

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Este trabalho consiste em realizar um estudo detalhado das vantagens e desvantagens da utilização do FDM (Filter Diagonalization Method) para a análise de dados obtidos pela sequência de Precessão Livre no Estado Estacionário (Steady State Free Precession - SSFP) para aquisição rápida de espectros de Ressonância Magnética Nuclear (RMN). No caso de RMN de baixa resolução, o procedimento de aquisição rápida, SSFP, é uma poderosa ferramenta para melhorar a relação sinal/ruído, apresentando muitas aplicações práticas. Apesar desse sucesso em baixa resolução, a SSFP não é rotineiramente utilizada para aplicações em RMN de alta resolução, provavelmente devido ao (1) artefatos provenientes do truncamento do sinal e (2) as anomalias causadas pela mistura do FID com o eco dos sinais. Existem na literatura inúmeras possíveis técnicas para suprimir este tipo de problemas, porém, nenhuma delas é capaz de realmente eliminar as anomalias geradas devido ao procedimento de aquisição rápida da SSFP. O FDM é um método paramétrico não-linear para fitar sinais no domínio do tempo. Seu objetivo fundamental é resolver o Problema da Inversão Harmônica, HIP, tornando-se robusto e adequado para a análise espectral de sinais no domínio do tempo nos casos onde a Transformada de Fourier falha. Neste trabalho, demonstramos que o FDM pode ser implementado para análises de sinais SSFP, com mais eficiência que os obtidos pelos procedimentos padrões de TF. A temperatura ambiente, espectros de RMN 13C de amostras de brucina, obtidos com tempo entre pulsos de 100ms, podem ser reproduzidos com boa relação sinal/ruído e alta resolução por meio do FDM. A limitação da análise por FDM é mais relevante nos casos de espectros com alta densidade de picos em uma determinada região espectral. Nestes casos, o curto período de observação do sinal na janela do tempo impõe uma série de limitações na resolução obtida pelo FDM.
This work consists in a detailed study of the advantages and disadvantages of the use of the Filter Diagonalization Method, FDM, for data analysis in Steady State Free Precession, SSFP, technique, usually employed to implement fast acquisition of Nuclear Magnetic Resonance, NMR, spectra. In the case of low resolution NMR using fast acquisition procedures, SSFP is a powerful tool to improve signal-to-noise ratio, presenting several important practical applications. Despite its success in the low resolution regime, SSFP is not a routine technique for high resolution applications, so far, mainly because of (1) truncation artifacts and (2) the intrinsic anomalies caused by admixture of free-induction-decay and echo signals. The literature reports many possible techniques to solve such kind of problems, but, none of them is capable to really eliminate the generated spectra anomalies caused by the fast acquisition procedure used in SSFP. FDM is a parametric method for non-liner fitting performed in the time domain. Its main goal is to solve the Harmonic Inversion Problem, HIP, making it robust and suitable for spectral analysis of time signals in the cases where the Fourier Transform, FT, technique fail. In this work we demonstrate that FDM can be used to implement the analysis of the SSFP data, with more efficiency than that achieve by appropriated FT procedures. Room temperature 13C NMR spectra of brucine samples, obtained from pulse sequences with 100 ms repetition time, can be reproduced with good signal-to-noise ratio and high resolution by means of the FDM. The limitation of the FDM analysis is more relevant in the case of spectra with a high density of peaks in a limited spectral frequency region. In these cases, the reduced short observation time window imposes serious limitation to the resolution achieved by the FDM.
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Strnad, Jiří. "Návrh malé multifunkční modelářské CNC frézky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-444277.

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This diploma thesis deals with the construction proposal of a small multifunctional modeller CNC milling machine that enables milling of aluminium alloys and 3D printing using the FDM method. Based on the research, analyzes and defined entry requirements the construction proposal is created and verified by calculations. The thesis contains a description of all the construction parts including the printhead, the tool tray and the safety cover. The other part of the thesis describes the machine geometry adjustment and specifies the choice of control system. The thesis includes a 3D model and the drawing documentation of selected structural nodes.
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Kleditzsch, Stefan, and Birgit Awiszus. "Modeling of Cylindrical Flow Forming Processes with Numerical and Elementary Methods." Universitätsbibliothek Chemnitz, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-97124.

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With flow forming – an incremental forming process – the final geometry of a component is achieved by a multitude of minor sequential forming steps. Due to this incremental characteristic associated with the variable application of the tools and kinematic shape forming, it is mainly suitable for small and medium quantities. For the extensive use of the process it is necessary to have appropriate simulation tools. While the Finite-Element-Analysis (FEA) is an acknowledged simulation tool for the modeling and optimization of forming technology, the use of FEA for the incremental forming processes is associated with very long computation times. For this reason a simulation method called FloSim, based on the upper bound method, was developed for cylindrical flow forming processes at the Chair of Virtual Production Engineering, which allows the simulation of the process within a few minutes. This method was improved by the work presented with the possibility of geometry computation during the process.
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Silva, Cíntia Maira Pereira da. "KBDM como ferramenta para processamento de sinais de Espectroscopia por Ressonância Magnética." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-12022014-075510/.

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A precisão e acurácia dos métodos mais utilizados atualmente de processamento de dados de espectroscopia por Ressonância Magnética (MRS), baseados na Transformada de Fourier (FT), requerem supressão apropriada (o que está longe de ser trivial) e aquisições longas para a obtenção de alta resolução espectral. Além disso, a FT tem dificuldades quando faltam dados no domínio de tempo, como, por exemplo, pela redução do tempo de aquisição, e consequente número de pontos adquiridos. Isto pode ocorrer, também, por artefatos na aquisição ou, ainda, seja pela exclusão intencional dos primeiros pontos do sinal para a eliminação de ressonâncias largas que estão distorcendo a linha de base no domínio da frequência. Neste estudo, propomos a utilização do Método de Diagonalização na Base de Krylov (KBDM) como uma alternativa a FT para algumas de suas limitações. O método ajusta sinais de experimentos de Free Induction Decay (FID) por uma soma de funções harmônicas complexas, amortecidas exponencialmente, permitindo uma fácil manipulação dos seus parâmetros de caracterização. O KBDM é numericamente mais efetivo para análise de sinais truncados e tem diversos recursos que possibilitam remover picos de forma mais eficiente, como por exemplo, o pico residual da água. Além disso, foi introduzida a possibilidade de quantificação de dados de MRS com o método. Para avaliar a sensibilidade, eficiência e reprodutibilidade do método para quantificar e analisar sinais truncados, foi proposto fazer simulações de espectros clínicos e experimentos em phantoms que representassem o ambiente metabólico do cérebro, para MRS de próton de diferentes níveis de ruídos e para pequenas variações do N-acetil aspartato (NAA). Com estes estudos pôde se comprovar a viabilidade do método para processar dados de MRS e verificar seu potencial na complementação das técnicas atualmente empregadas, especialmente quando uma resolução espectral e temporal maior que o limite imposto pela Relação de Incerteza do formalismo de Fourier é necessária. Além disso, uma desejável facilidade de manipulação de picos específicos (por exemplo, exclusão e quantificação) é proporcionada pelo método. Como perspectivas animadoras deste trabalho esperamos a introdução do KBDM como uma técnica eficiente e coadjuvante ao Imageamento de Ressonância Magnética funcional (fMRI), auxiliando estudos de funções cerebrais, em sequências de MRS para identificar uma rápida variação das linhas associadas as atividades metabólicas dos cérebros.
The precision and accuracy of the most widely used methods to perform Magnetic Resonance Spectroscopy (MRS) data processing based on the Fourier Transform (FT), require appropriate suppression (which is far from trivial) and long acquisitions to obtain high spectral resolution. Furthermore, FT poses difficulty when there are missing data in the time domain. This occurs because of reduction of the acquisition time and consequently also in the number of acquired points, or because of artifacts during acquisition, or even intentional exclusion of the first signal points for the elimination of broad resonances that are producing the distorted baseline in the frequency domain. In this study, we propose the use of the Krylov Basis Diagonalization Method (KBDM) formalism as an alternative to some of FT limitations. The method adjusts signals of Free Induction Decay (FID) experiments with a sum of complex harmonic functions, exponentially damped, allowing easy manipulation of its characterization parameters. The KBDM is numerically more effective for truncated signal analysis and has several features that make it possible to remove peaks more efficiently, such as the residual water peak. Moreover, we introduced the possibility of quantification of MRS data with the described method. To evaluate the sensitivity, efficiency and reproducibility of the method for quantifying and analyzing truncated signals, and through the clinical spectra simulations and experiments in phantoms that would represent the brain metabolic environment, we proposed to perform proton MRS at different noise levels and with small variations of N- acetyl aspartate (NAA) metabolite. These studies allowed to prove the feasibility of the method to process MRS data and verified its potential in complementing techniques currently employed, especially when a greater temporal and spectral resolution is required, more than the limit imposed by the Uncertainty Relation of FT formalism. Furthermore, it is also a desirable effortless tool of handling specific peaks (e.g., exclusion and quantification). Exciting prospects from this work include the introduction of KBDM as an efficient and adjuvant technique to functional Magnetic Resonance Imaging (fMRI), for studying the brain functions, in MRS sequence to identify rapid variation in spectroscopic lines associated to metabolic activities in the brain.
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Beuchler, Sven. "Wavelet preconditioners for the p-version of the fem." Universitätsbibliothek Chemnitz, 2006. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200600607.

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In this paper, we consider domain decomposition preconditioners for a system of linear algebraic equations arising from the p-version of the fem. We propose several multi-level preconditioners for the Dirichlet problems in the sub-domains in two and three dimensions. It is proved that the condition number of the preconditioned system is bounded by a constant independent of the polynomial degree. The proof uses interpretations of the p-version element stiffness matrix and mass matrix on [-1,1] as h-version stiffness matrix and weighted mass matrix. The analysis requires wavelet methods.
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Eibner, Tino, and Jens Markus Melenk. "A local error analysis of the boundary concentrated FEM." Universitätsbibliothek Chemnitz, 2006. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200601440.

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The boundary concentrated finite element method is a variant of the hp-version of the FEM that is particularly suited for the numerical treatment of elliptic boundary value problems with smooth coefficients and boundary conditions with low regularity or non-smooth geometries. In this paper we consider the case of the discretization of a Dirichlet problem with exact solution $u \in H^{1+\delta}(\Omega)$ and investigate the local error in various norms. We show that for a $\beta > 0$ these norms behave as $O(N^{−\delta−\beta})$, where $N$ denotes the dimension of the underlying finite element space. Furthermore, we present a new Gauss-Lobatto based interpolation operator that is adapted to the case non-uniform polynomial degree distributions.
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Books on the topic "FDM method"

1

Nakahashi, Kazuhiro. FDM-FEM zonal method for viscous flow computations over multiple-bodies. Tokyo: National Aerospace Laboratory, 1987.

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John, Robinson. Early FEM pioneers. Wimbourne, Eng: Robinson and Associates, 1985.

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Matthias, Kraus, ed. Steel structures: Design using FEM. Berlin: Wilhelm Ernst & Sohn, 2011.

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Blaauwendraad, J. Plates and FEM: Surprises and Pitfalls. Dordrecht: Springer Science+Business Media B.V., 2010.

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Applied metal forming: Using FEM analysis. Cambridge: Cambridge University Press, 2010.

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Rolf, Steinbuch. Simulation im konstruktiven Maschinenbau: Anwendung von FEM- und verwandten Systemen in der Konstruktion. München: Fachbuchverlag Leipzig im Carl Hanser Verlag, 2004.

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Löhner, Rainald. Finite element flux-corrected transport (FEM-FCT) for the Euler and Navier-Stokes equations. Hampton, Va: ICASE, 1987.

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FEM: Grundlagen und Anwendungen der Finite-Element-Methode im Maschinen- und Fahrzeugbau. 7th ed. Wiesbaden: Friedr. Vieweg & Sohn Verlag, 2007.

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Institut mirovoĭ literatury imeni A.M. Gorʹkogo. Komissii︠a︡ po izuchenii︠u︡ tvorchestva F.M. Dostoevskogo., ed. "Soznatʹ i skazatʹ": "Realizm v vysshem smysle" kak tvorcheskiĭ metod F.M. Dostoevskogo. Moskva: Raritet, 2005.

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Klein, Bernd. FEM: Grundlagen und Anwendungen der Finite-Element-Methode im Maschinen- und Fahrzeugbau : mit 12 Fallstudien und 20 U bungsaufgaben. 8th ed. Wiesbaden: Vieweg + Teubner, 2010.

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Book chapters on the topic "FDM method"

1

Beilina, L., and C. Johnsson. "Hybrid FEM/FDM method for an inverse scattering problem." In Numerical Mathematics and Advanced Applications, 545–56. Milano: Springer Milan, 2003. http://dx.doi.org/10.1007/978-88-470-2089-4_51.

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Xue, Xiang, Jing Tian, and Guoming Xiu. "Numerical Simulation of Thermal Stress in Castings Using FDM/FEM Integrated Method." In Materials Science Forum, 85–90. Stafa: Trans Tech Publications Ltd., 2005. http://dx.doi.org/10.4028/0-87849-969-5.85.

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Khawaja, Hassan A. "Solution of Pure Scattering Radiation Transport Equation (RTE) Using Finite Difference Method (FDM)." In Image Analysis, 492–501. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-59126-1_41.

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Mochizuki, Tatsuya, and Takehiro Kawamura. "3D Printer of Five-Axis Laminate-Shaping with FDM Method and Its Application." In Advances in Intelligent Systems and Computing, 903–11. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-95588-9_77.

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Choi, Bong Hak, Woo Jung Kim, Chong Du Cho, Si Young Kwak, and Cheong Kil Choi. "FDM/FEM Hybrid Method with a Systematic Field Data Conversion Procedure for Thermal Stress Analysis in Casting Process." In Experimental Mechanics in Nano and Biotechnology, 1205–8. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-415-4.1205.

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Bai, Bing, Dengyu Rao, Nan Wu, and Tao Xu. "SPH-FDM Boundary Method for the Heat Conduction of Geotechnical Materials Considering Phase Transition." In Springer Series in Geomechanics and Geoengineering, 291–95. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-97112-4_65.

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Fröhlich, Peter. "Finite Elemente Methode." In FEM-Anwendungspraxis, 12–23. Wiesbaden: Vieweg+Teubner Verlag, 2005. http://dx.doi.org/10.1007/978-3-663-10053-9_2.

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Klein, Bernd. "Grundlagen der Nichtlinearen Finiten-Element-Methode." In FEM, 226–38. Wiesbaden: Vieweg+Teubner Verlag, 1990. http://dx.doi.org/10.1007/978-3-322-85604-3_10.

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Klein, Bernd. "Grundgleichungen der Linearen Finite-Element-Methode." In FEM, 11–32. Wiesbaden: Vieweg+Teubner Verlag, 1990. http://dx.doi.org/10.1007/978-3-322-85604-3_3.

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Klein, Bernd. "Das Konzept der Finite-Element-Methode." In FEM, 42–89. Wiesbaden: Vieweg+Teubner Verlag, 1990. http://dx.doi.org/10.1007/978-3-322-85604-3_5.

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Conference papers on the topic "FDM method"

1

Liu, Qiang, Lan Kang, F. Barlat, Y. H. Moon, and M. G. Lee. "Springback Compensation Based on FDM-DTF Method." In NUMIFORM 2010: Proceedings of the 10th International Conference on Numerical Methods in Industrial Forming Processes Dedicated to Professor O. C. Zienkiewicz (1921–2009). AIP, 2010. http://dx.doi.org/10.1063/1.3457526.

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Fernando, Greshan. "Hybrid Numerical Method for Heat Transfer Analysis of Complex 3D Geometries." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-33085.

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The heat transfer analysis of systems with complex 3D geometries is usually done by numerical methods. Finite Element Method (FEM) and Finite Difference Methods (FDM) are widely used for this purpose. Complex geometries are accurately analyzed by FEM method. However, FEM solutions can be computationally inefficient for thermal problems that have high mesh densities with complex boundary conditions and variable material properties. On the other hand, Finite Difference method (FDM) is difficult to apply for complex geometric shapes. A hybrid numerical approach that combines the advantages of FDM and FEM has been integrated into a thermal simulation code. The hybrid technique has been implemented using object oriented programming techniques in a PC environment. A comparison of the computational efficiency of the two methods has been presented.
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Cui, Weiwei, and Zhigang Cao. "FDM array based dual channel speech enhancement method." In 2008 9th International Conference on Signal Processing (ICSP 2008). IEEE, 2008. http://dx.doi.org/10.1109/icosp.2008.4697150.

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Hu, Changhong, Kangping Liao, and Wengyang Duan. "VIV Simulation of 2-D Deformable Cylinder Using Coupled FDM/FEM Method." In ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/omae2012-83641.

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In this work a coupled finite difference method and finite element method (FDM/FEM) is developed for numerical simulation of vortex induced vibration (VIV) phenomenon with an elastically deformable circular cylinder. The algorithm is based on a FDM with CIP (Constraint Interpolation Profile) method to fluid dynamics and a FEM to solve structural dynamics. Coupling between FDM and FEM is realized by BGS (Block Gauss-Seidel) procedure. IB (Immersed Boundary) method is applied for data transferring on the interface between fluid and structure. In this paper, numerical simulations of a 2-D circular cylinder at low Reynolds number are carried out. The effect of stiffness of the cylinder shell on the vortex shedding is investigated.
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Dvorak, Karel. "3D model preparing for rapid prototyping by FDM method." In 2017 8th International Conference on Mechanical and Aerospace Engineering (ICMAE). IEEE, 2017. http://dx.doi.org/10.1109/icmae.2017.8038611.

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Kannan, S., D. Senthilkumaran, and K. Elangovan. "Development of composite materials by rapid prototyping technology using FDM method." In 2013 International Conference on Current Trends in Engineering and Technology (ICCTET). IEEE, 2013. http://dx.doi.org/10.1109/icctet.2013.6675966.

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Yangyang, Chen, and Wang Yanbin. "Numerical Simulation of Basin-edge Effects with Hybrid PSM/FDM Method." In Near Surface Geophysics Asia Pacific Conference, Beijing, China 17-19 July 2013. Society of Exploration Geophysicists, Australian Society of Exploration Geophysicists, Chinese Geophysical Society, Korean Society of Earth and Exploration Geophysicists, and Society of Exploration Geophysicists of Japan, 2013. http://dx.doi.org/10.1190/nsgapc2013-114.

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Husain, Nor Masharah. "Modelling Of Pck Competency Of Programming Teachers Through Fuzzy Delphi Method (Fdm)." In AIMC 2017 - Asia International Multidisciplinary Conference. Cognitive-Crcs, 2018. http://dx.doi.org/10.15405/epsbs.2018.05.28.

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Yin He, Wen Quangang, Lin Gang, and Li Tingting. "Research on the control method of 3D printer based on FDM technology." In 2017 8th International Conference on Mechanical and Intelligent Manufacturing Technologies (ICMIMT). IEEE, 2017. http://dx.doi.org/10.1109/icmimt.2017.7917439.

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Zhang, Yaqi, and Vadim Shapiro. "Linear Time Thermal Simulation of FDM Process." In ASME 2017 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/detc2017-68293.

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Like many other additive manufacturing processes, FDM process is driven by a moving heat source, and temperature history plays an important role in determining the mechanical properties and geometry of the final parts. Thermal simulation of FDM is challenging due to geometric complexity of manufacturing process and inherent computational complexity which requires numerical solution at every time increment of the process. we describe a new approach to thermal simulation of the FDM process, formulated as an explicit finite difference method that is applied directly on as-manufactured model described by a typical manufacturing process plan. The thermal model accounts for most relevant thermal effects including heat convection and radiation to the environment, heat conduction with build platform and between adjacent roads (and adjacent layers). We show that the proposed simulation method achieves linear time complexity. This implies that the simulation not only scales to handle 3D printed components of arbitrary complexity but also can achieve real-time performance.
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Reports on the topic "FDM method"

1

Zheng, Jinhui, Matteo Ciantia, and Jonathan Knappett. On the efficiency of coupled discrete-continuum modelling analyses of cemented materials. University of Dundee, December 2021. http://dx.doi.org/10.20933/100001236.

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Computational load of discrete element modelling (DEM) simulations is known to increase with the number of particles. To improve the computational efficiency hybrid methods using continuous elements in the far-field, have been developed to decrease the number of discrete particles required for the model. In the present work, the performance of using such coupling methods is investigated. In particular, the coupled wall method, known as the “wall-zone” method when coupling DEM and the continuum Finite Differences Method (FDM) using the Itasca commercial codes PFC and FLAC respectively, is here analysed. To determine the accuracy and the efficiency of such a coupling approach, 3-point bending tests of cemented materials are simulated numerically. To validate the coupling accuracy first the elastic response of the beam is considered. The advantage of employing such a coupling method is then investigated by loading the beam until failure. Finally, comparing the results between DEM, DEM-FDM coupled and FDM models, the advantages and disadvantages of each method are outlined.
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MATTHAI, Stephan K., Julian MINDEL, and Hamidreza MAGHAMI-NICK. A Hybrid (FEM - Node-Centered FVM) Method with Special Treatment of Wells and Material Discontinuitues for Fast and Spatially Adaptive Simulation of Coupled Reservoir Processes. Cogeo@oeaw-giscience, September 2011. http://dx.doi.org/10.5242/iamg.2011.0160.

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Dolbow, John, Ziyu Zhang, Benjamin Spencer, and Wen Jiang. Fracture Capabilities in Grizzly with the extended Finite Element Method (X-FEM). Office of Scientific and Technical Information (OSTI), September 2015. http://dx.doi.org/10.2172/1244633.

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Gumerov, Nail A., and Ramani Duraiswami. Efficient FMM Accelerated Vortex Methods in Three Dimensions via the Lamb-Helmholtz Decomposition. Fort Belvoir, VA: Defense Technical Information Center, January 2012. http://dx.doi.org/10.21236/ada560003.

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Vorobiev, O. Simple Common Plane contact algorithm for explicit FE/FD methods. Office of Scientific and Technical Information (OSTI), December 2006. http://dx.doi.org/10.2172/899442.

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Morris, Kristen D., Michelle Teti, Cole Young, and Abigail Rolbiecki. Photovoice: A user-centered design method to understand apparel needs of Female to Male (FTM) in gender identity and expression. Ames: Iowa State University, Digital Repository, 2017. http://dx.doi.org/10.31274/itaa_proceedings-180814-427.

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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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Wei, Fulu, Ce Wang, Xiangxi Tian, Shuo Li, and Jie Shan. Investigation of Durability and Performance of High Friction Surface Treatment. Purdue University, 2021. http://dx.doi.org/10.5703/1288284317281.

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The Indiana Department of Transportation (INDOT) completed a total of 25 high friction surface treatment (HFST) projects across the state in 2018. This research study attempted to investigate the durability and performance of HFST in terms of its HFST-pavement system integrity and surface friction performance. Laboratory tests were conducted to determine the physical and mechanical properties of epoxy-bauxite mortar. Field inspections were carried out to identify site conditions and common early HFST distresses. Cyclic loading test and finite element method (FEM) analysis were performed to evaluate the bonding strength between HFST and existing pavement, in particular chip seal with different pretreatments such as vacuum sweeping, shotblasting, and scarification milling. Both surface friction and texture tests were undertaken periodically (generally once every 6 months) to evaluate the surface friction performance of HFST. Crash records over a 5-year period, i.e., 3 years before installation and 2 years after installation, were examined to determine the safety performance of HFST, crash modification factor (CMF) in particular. It was found that HFST epoxy-bauxite mortar has a coefficient of thermal expansion (CTE) significantly higher than those of hot mix asphalt (HMA) mixtures and Portland cement concrete (PCC), and good cracking resistance. The most common early HFST distresses in Indiana are reflective cracking, surface wrinkling, aggregate loss, and delamination. Vacuum sweeping is the optimal method for pretreating existing pavements, chip seal in particular. Chip seal in good condition is structurally capable of providing a sound base for HFST. On two-lane highway curves, HFST is capable of reducing the total vehicle crash by 30%, injury crash by 50%, and wet weather crash by 44%, and providing a CMF of 0.584 in Indiana. Great variability may arise in the results of friction tests on horizontal curves by the use of locked wheel skid tester (LWST) due both to the nature of vehicle dynamics and to the operation of test vehicle. Texture testing, however, is capable of providing continuous texture measurements that can be used to calculate a texture height parameter, i.e., mean profile depth (MPD), not only for evaluating friction performance but also implementing quality control (QC) and quality assurance (QA) plans for HFST.
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