Journal of Multiscale Modelling最新文献

{"title":"Multiscale Analysis of Structures Composed of Metal Matrix Composites Considering Phase Debonding","authors":"G. Fernandes, Amanda S. Furtado, J. J. C. Pituba, E. A. S. Neto","doi":"10.1142/S1756973717400042","DOIUrl":"https://doi.org/10.1142/S1756973717400042","url":null,"abstract":"Multiscale analyses considering the stretching problem in plates composed of metal matrix composites (MMC) have been performed using a coupled BEM/FEM model, where the boundary element method (BEM) and the finite element method (FEM) models, respectively, the macrocontinuum and the material microstructure, denoted as representative volume element (RVE). The RVE matrix zone behavior is governed by the von Mises elasto-plastic model while elastic inclusions have been incorporated to the matrix to improve the material mechanical properties. To simulate the microcracks evolution at the interface zone surrounding the inclusions, a modified cohesive fracture model has been adopted, where the interface zone is modeled by means of cohesive contact finite elements to capture the effects of phase debonding. Thus, this paper investigates how this phase debonding affects the microstructure mechanical behavior and consequently affects the macrostructure response in a multiscale analysis. For that, initially, only RVEs...","PeriodicalId":43242,"journal":{"name":"Journal of Multiscale Modelling","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2017-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S1756973717400042","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49336979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spherical Harmonics Expansion of Fundamental Solutions and Their Derivatives for Homogeneous Elliptic Operators","authors":"V. Gulizzi, I. Benedetti, A. Milazzo","doi":"10.1142/S1756973717400066","DOIUrl":"https://doi.org/10.1142/S1756973717400066","url":null,"abstract":"In this work, a unified scheme for computing the fundamental solutions of a three-dimensional homogeneous elliptic partial differential operator is presented. The scheme is based on the Rayleigh expansion and on the Fourier representation of a homogeneous function. The scheme has the advantage of expressing the fundamental solutions and their derivatives up to the desired order without any term-by-term differentiation. Moreover, the coefficients of the series need to be computed only once, thus making the presented scheme attractive for numerical implementation. The scheme is employed to compute the fundamental solution of isotropic elasticity showing that the spherical harmonics expansions provide the exact expressions. Then, the accuracy of the scheme is assessed by computing the fundamental solutions of a generally anisotropic magneto-electro-elastic material.","PeriodicalId":43242,"journal":{"name":"Journal of Multiscale Modelling","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2017-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S1756973717400066","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43340860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-Scaling Homogenization Process for Nodular Cast Iron Using BEM","authors":"Adrián Alberto Betancur Arroyave, C. Anflor","doi":"10.1142/S1756973717400054","DOIUrl":"https://doi.org/10.1142/S1756973717400054","url":null,"abstract":"In this work, a multi-scaling homogenization process using boundary element formulation (BEM) for modeling a two-dimensional multi-phase microstructure containing irregular’s inclusions is presented. The BEM is very attractive for multiscale modeling tools for heterogeneous materials. In this approach, the iterative inhomogeneity discretization of the external boundary is disregarded, leading to a computational low cost. This approach was used for solving the elastic problem of a representative volume element (RVE) and the field theory medium. The main goal relies on finding the effective properties of micro-heterogeneous materials within a homogeneous and orthotropic matrix. Expressions for evaluating the effective properties under Plane Stress (PT) for orthotropic materials were also presented. Generally, the numerical models consider the graphite nodules as voids for GGG-40 and the roundness is close circular geometry. In this sense, a nodular cast iron GGG-40 microgram was obtained by X-ray computed t...","PeriodicalId":43242,"journal":{"name":"Journal of Multiscale Modelling","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2017-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S1756973717400054","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"64017355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectral BEM for the Analysis of Wave Propagation and Fracture Mechanics","authors":"Jun Li, Z. S. Khodaei, M. Aliabadi","doi":"10.1142/S1756973717400078","DOIUrl":"https://doi.org/10.1142/S1756973717400078","url":null,"abstract":"This paper presents a spectral boundary element formulation for analysis of structures subjected to dynamic loading. Two types of spectral elements based on Lobatto polynomials and Legendre polynomials are used. Two-dimensional analyses of elastic wave propagation in solids with and without cracks are carried out in the Laplace frequency domain with both conventional BEM and the spectral BEM. By imposing the requirement of the same level of accuracy, it was found that the use of spectral elements, compared with conventional quadratic elements, reduced the total number of nodes required for modeling high-frequency wave propagation. Benchmark examples included a simple one-dimensional bar for which analytical solution is available and a more complex crack problem where stress intensity factors were evaluated. Special crack tip elements are developed for the first time for the spectral elements to accurately model the crack tip fields. Although more integration points were used for the integrals associated w...","PeriodicalId":43242,"journal":{"name":"Journal of Multiscale Modelling","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2017-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S1756973717400078","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45986683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Efficient Hybrid Implementation of MLPG Method","authors":"M. Barbosa, E. Fontes, J. Telles, W. J. Santos","doi":"10.1142/S1756973717400029","DOIUrl":"https://doi.org/10.1142/S1756973717400029","url":null,"abstract":"The computational implementation of moving least squares (MLS) shape functions is an important step to consider in some versions of the meshless local Petrov–Galerkin (MLPG) method for a variety of two-dimensional engineering problems. Here, the usage of conventional Gaussian quadrature in the MLPG may require an excessive number integration points to achieve acceptable accuracy. In addition, since for each integration point a search for nearby points contributing to the construction of the MLS shape functions is required, considerable increase in computational cost is often observed. Herein, an efficient hybrid implementation of CPU and GPU is proposed to accelerate the construction of MLS shape functions for MLPG. To this end, a new K-d-Tree (K-dimensional tree)-based data structure is introduced in order to accelerate the calculations involving computational geometry formulas such as MLS. The results are compared for implementations in CPU and CPU+GPU using K-d-Tree with the traditional algorithm of br...","PeriodicalId":43242,"journal":{"name":"Journal of Multiscale Modelling","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2017-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S1756973717400029","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42624618","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-Fidelity Modeling-Based Structural Reliability Analysis with the Boundary Element Method","authors":"L. Morse, Z. S. Khodaei, M. H. Aliabadi","doi":"10.1142/S1756973717400017","DOIUrl":"https://doi.org/10.1142/S1756973717400017","url":null,"abstract":"In this work, a method for the application of multi-fidelity modeling to the reliability analysis of 2D elastostatic structures using the boundary element method (BEM) is proposed. Reliability analyses were carried out on a rectangular plate with a center circular hole subjected to uniaxial tension using Monte Carlo simulations (MCS), the first-order reliability method (FORM), and the second-order reliability method (SORM). Two BEM models were investigated, a low-fidelity model (LFM) of 20 elements and a high-fidelity model (HFM) of 100 elements. The response of these models at several design points was used to create multi-fidelity models (MFMs) utilizing second-order polynomial response surfaces and their reliability, alongside that of the LFM and the HFM, was evaluated. Results show that the MFMs that directly called the LFM were significantly superior in terms of accuracy to the LFM, achieving very similar levels of accuracy to the HFM, while also being of similar computational cost to the LFM. These ...","PeriodicalId":43242,"journal":{"name":"Journal of Multiscale Modelling","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2017-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S1756973717400017","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48951210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Finite Element Analysis of Cylindrical Inclusions in Polycrystalline Nickel Alloys","authors":"E. Bonifaz, A. Alban, A. Czekanski","doi":"10.1142/S1756973718500038","DOIUrl":"https://doi.org/10.1142/S1756973718500038","url":null,"abstract":"Inspired by nanotubes, a 3D finite element model was developed to simulate the influence of cylindrical inclusions on the polycrystalline mechanical behavior of Nickel alloys. A dislocation based strain hardening model, constructed in the so-called Kocks–Mecking framework, is used as the main strategy for the constitutive modeling of individual bulk grains. To determine the influence of the inclusions distribution, the direction of applied load and the size of the matrix phase on the inelastic stress–strain distribution, the digital microstructure code DREAM.3D was coupled to ABAQUS[Formula: see text] finite element code through a MatLab[Formula: see text] program. Four affordable computational representative volume elements (RVEs) meshes of two different edge sizes and two different inclusion distributions were tested to investigate the relation between micro and macro deformation and stress variables. The virtual specimens, subjected to continuous monotonic strain loading conditions, were constrained with random periodic boundary conditions. The difference in crystallographic orientation, which evolves in the process of straining, and the incompatibility of deformation between neighboring grains were accounted for by the introduction of single crystal averaged Taylor factors, single crystal Young’s modulus, single phase elastic modulus and the evolution of geometrically necessary dislocation density. The effects of single crystal Young’s modulus, inclusion distribution and direction of the applied load upon the aggregate local response are clearly observed. Results demonstrate a strong dependence of flow stress and plastic strain on phase type, Young’s modulus values and direction of the applied load, but slightly on matrix grain size. The stress–strain curve extension and the variation in the elastic limit of the individual inclusions depend on the inclusion-matrix Young’s modulus difference and applied load direction. The difference in curve extension and the difference in elastic limit decrease as the Young’s modulus of the single crystal inclusion approach the Young’s modulus of the matrix majoritary phase, while the resistance to flow increases when the applied load is perpendicular to the inclusion longitudinal axis.","PeriodicalId":43242,"journal":{"name":"Journal of Multiscale Modelling","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2017-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S1756973718500038","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49500146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Advanced Discrete Model with Applications in Medical Science","authors":"B. Para, T. R. Jan","doi":"10.1142/S1756973718500014","DOIUrl":"https://doi.org/10.1142/S1756973718500014","url":null,"abstract":"In this paper, we introduce a new discrete model by compounding two parameter discrete Weibull distribution with Beta distribution of first kind. The proposed model can be nested to different compound distributions on specific parameter settings. The model is a good competitive for zero-inflated models. In addition, we present the basic properties of the new distribution and discuss unimodality, failure rate functions and index of dispersion. Finally, the model is examined with real-life count data from medical sciences to investigate the suitability of the proposed model.","PeriodicalId":43242,"journal":{"name":"Journal of Multiscale Modelling","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2017-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S1756973718500014","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42281529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Free Vibration Analysis of Carbon Fiber-Carbon Nanotube-Polymer Matrix Composite Plates by a Finite Element-Based Multi-Scale Modeling Approach","authors":"M. Ahmadi, R. Ansari, H. Rouhi","doi":"10.1142/S1756973718500026","DOIUrl":"https://doi.org/10.1142/S1756973718500026","url":null,"abstract":"The vibrational behavior of polymer matrix nanocomposite plates reinforced with carbon fibers (CFs) and carbon nanotubes (CNTs) is studied using the finite element method based on a multi-scale modeling approach. The influences of nano- and micro-scale are coupled through a two-step procedure. First, CNTs are dispersed into the polymer matrix. In the selected representative volume element (RVE), interphase due to chemical interaction between CNT and polymer matrix is considered. Also, the state of dispersion of CNTs into the matrix is assumed to be random. In the second step, CFs are randomly distributed in the reinforced polymer with CNTs. The reinforcement is carried out for various volume fractions of CFs and CNTs. Two three-dimensional models including the brick and shell ones are used to generate the results. Moreover, the analysis is presented for square plates under different types of boundary conditions. The effect of nanocomposite thickness on its vibrational response is also investigated.","PeriodicalId":43242,"journal":{"name":"Journal of Multiscale Modelling","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2017-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S1756973718500026","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45163325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stress Wave Propagation in Cracked Geological Solids Using Finite Difference Scheme","authors":"P. Kakavas, Nicos A. Kalapodis","doi":"10.1142/S1756973717500093","DOIUrl":"https://doi.org/10.1142/S1756973717500093","url":null,"abstract":"The aim of this study is the numerical computation of the wave propagation in crack geological solids. The finite difference method was applied to solve the differential equations involved in the problem. Since the problem is symmetric, we prefer to use this technique instead of the finite element method and/or boundary elements technique. A comparison of the numerical results with analytical solutions is provided.","PeriodicalId":43242,"journal":{"name":"Journal of Multiscale Modelling","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2017-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S1756973717500093","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43197338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}