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  Subjects -> ENGINEERING (Total: 2255 journals)
    - CHEMICAL ENGINEERING (189 journals)
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    - ENGINEERING (1196 journals)
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ENGINEERING (1196 journals)            First | 1 2 3 4 5 6 | Last

Showing 401 - 600 of 1205 Journals sorted alphabetically
IET Optoelectronics     Hybrid Journal   (Followers: 1)
IET Radar, Sonar & Navigation     Hybrid Journal   (Followers: 24)
IET Renewable Power Generation     Hybrid Journal   (Followers: 9)
IET Science, Measurement & Technology     Hybrid Journal   (Followers: 2)
IET Signal Processing     Hybrid Journal   (Followers: 15)
IETE Journal of Research     Open Access   (Followers: 8)
IETE Technical Review     Open Access   (Followers: 8)
IIE Transactions     Hybrid Journal   (Followers: 2)
Implementation Science     Open Access   (Followers: 13)
Indian Journal of Biotechnology (IJBT)     Open Access   (Followers: 2)
Indonesian Journal of Science and Technology     Open Access  
Industrial Data     Open Access   (Followers: 1)
Industrie et Technologies     Full-text available via subscription   (Followers: 15)
Informatik-Spektrum     Hybrid Journal   (Followers: 1)
Ingeniare : Revista Chilena de Ingenieria     Open Access  
Ingenieria     Open Access  
Ingeniería     Open Access  
Ingenieria de Recursos Naturales y del Ambiente     Open Access  
Ingeniería e Investigación     Open Access  
Ingeniería Energética     Open Access  
Ingenieria Industrial. Actualidad y Nuevas Tendencias     Open Access  
Ingeniería Investigación y Desarrollo     Open Access  
Ingeniería solidaria     Open Access   (Followers: 1)
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Ingeniería y Desarrollo     Open Access  
Ingenieria y Universidad     Open Access  
Ingeniería, Investigación y Tecnología     Open Access  
Ingenius : Revista de Ciencia y Tecnología     Open Access  
Innovare : Revista de ciencia y tecnología     Open Access  
Instrumentation Science & Technology     Hybrid Journal   (Followers: 7)
Integration, the VLSI Journal     Hybrid Journal   (Followers: 5)
Intelligent Control and Automation     Open Access   (Followers: 6)
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (Followers: 8)
Interface Science and Technology     Full-text available via subscription  
Intermetallics     Hybrid Journal   (Followers: 21)
International Archives of Science and Technology     Open Access  
International Communications in Heat and Mass Transfer     Hybrid Journal   (Followers: 14)
International conference KNOWLEDGE-BASED ORGANIZATION     Open Access  
International Heat Treatment and Surface Engineering     Hybrid Journal   (Followers: 3)
International Journal for Numerical Methods in Engineering     Hybrid Journal   (Followers: 29)
International Journal for Numerical Methods in Fluids     Hybrid Journal   (Followers: 19)
International Journal for Simulation and Multidisciplinary Design Optimization     Open Access   (Followers: 2)
International Journal for the History of Engineering & Technology     Hybrid Journal   (Followers: 7)
International Journal of Abrasive Technology     Hybrid Journal   (Followers: 2)
International Journal of Adaptive Control and Signal Processing     Hybrid Journal   (Followers: 2)
International Journal of Adhesion and Adhesives     Hybrid Journal   (Followers: 16)
International Journal of Advancements in Technology     Open Access   (Followers: 1)
International Journal of Advances in Applied Sciences     Open Access   (Followers: 4)
International Journal of Advances in Engineering Sciences     Open Access   (Followers: 3)
International Journal of Advances in Engineering Sciences and Applied Mathematics     Hybrid Journal   (Followers: 1)
International Journal of Advances in Engineering, Science and Technology     Open Access   (Followers: 4)
International Journal of Aerodynamics     Hybrid Journal   (Followers: 17)
International Journal of Aerospace Innovations     Full-text available via subscription   (Followers: 17)
International Journal of Air-Conditioning and Refrigeration     Hybrid Journal   (Followers: 7)
International Journal of Antennas and Propagation     Open Access   (Followers: 9)
International Journal of Applied Ceramic Technology     Hybrid Journal   (Followers: 7)
International Journal of Applied Power Engineering     Open Access   (Followers: 4)
International Journal of Architectural Computing     Full-text available via subscription   (Followers: 5)
International Journal of Automation and Control Engineering     Open Access   (Followers: 2)
International Journal of Automotive Technology and Management     Hybrid Journal   (Followers: 5)
International Journal of Autonomic Computing     Hybrid Journal   (Followers: 1)
International Journal of Autonomous and Adaptive Communications Systems     Hybrid Journal   (Followers: 4)
International Journal of Basic and Applied Sciences     Open Access   (Followers: 4)
International Journal of Bifurcation and Chaos     Hybrid Journal   (Followers: 2)
International Journal of Biomedical and Clinical Engineering     Full-text available via subscription   (Followers: 4)
International Journal of Biomedical Imaging     Open Access   (Followers: 5)
International Journal of Cast Metals Research     Hybrid Journal  
International Journal of Circuit Theory and Applications     Hybrid Journal   (Followers: 2)
International Journal of Coal Science & Technology     Open Access   (Followers: 1)
International Journal of Collaborative Engineering     Hybrid Journal  
International Journal of Combinatorics     Open Access   (Followers: 1)
International Journal of Communication Systems     Hybrid Journal   (Followers: 2)
International Journal of Computer Aided Engineering and Technology     Hybrid Journal   (Followers: 1)
International Journal of Computer Applications in Technology     Hybrid Journal   (Followers: 3)
International Journal of Control Science and Engineering     Open Access   (Followers: 5)
International Journal of Control, Automation and Systems     Hybrid Journal   (Followers: 12)
International Journal of Corrosion     Open Access   (Followers: 10)
International Journal of Crashworthiness     Hybrid Journal   (Followers: 7)
International Journal of Design Engineering     Hybrid Journal   (Followers: 14)
International Journal of Digital Multimedia Broadcasting     Open Access   (Followers: 5)
International Journal of Education and Management Engineering     Open Access   (Followers: 2)
International Journal of Education Economics and Development     Hybrid Journal   (Followers: 3)
International Journal of Embedded Systems     Hybrid Journal   (Followers: 5)
International Journal of Emerging Multidisciplinary Fluid Sciences     Full-text available via subscription   (Followers: 1)
International Journal of Energy Optimization and Engineering     Hybrid Journal   (Followers: 3)
International Journal of Engine Research     Hybrid Journal   (Followers: 1)
International Journal of Engineering & Technology     Open Access   (Followers: 4)
International Journal of Engineering and Manufacturing     Open Access   (Followers: 1)
International Journal of Engineering and Technologies     Open Access  
International Journal of Engineering Education     Full-text available via subscription   (Followers: 6)
International Journal of Engineering Management and Economics     Hybrid Journal   (Followers: 3)
International Journal of Engineering Mathematics     Open Access   (Followers: 2)
International Journal of Engineering Pedagogy     Open Access  
International Journal of Engineering Practical Research     Open Access  
International Journal of Engineering Research in Africa     Full-text available via subscription   (Followers: 1)
International Journal of Engineering Science     Hybrid Journal   (Followers: 6)
International Journal of Engineering Systems Modelling and Simulation     Hybrid Journal   (Followers: 8)
International Journal of Engineering, Science and Technology     Open Access  
International Journal of Engineering, Social Justice, and Peace     Open Access   (Followers: 4)
International Journal of Environmental Engineering     Hybrid Journal   (Followers: 6)
International Journal of Experimental Design and Process Optimisation     Hybrid Journal   (Followers: 5)
International Journal of Fatigue     Hybrid Journal   (Followers: 33)
International Journal of Flow Control     Full-text available via subscription   (Followers: 5)
International Journal of Foresight and Innovation Policy     Hybrid Journal   (Followers: 7)
International Journal of Fracture     Hybrid Journal   (Followers: 11)
International Journal of Geo-Engineering     Open Access  
International Journal of Geotechnical Engineering     Hybrid Journal   (Followers: 5)
International Journal of Grid and Utility Computing     Hybrid Journal  
International Journal of Heat and Fluid Flow     Hybrid Journal   (Followers: 31)
International Journal of Heat and Mass Transfer     Hybrid Journal   (Followers: 142)
International Journal of Heavy Vehicle Systems     Hybrid Journal   (Followers: 6)
International Journal of Hypersonics     Full-text available via subscription   (Followers: 4)
International Journal of Imaging Systems and Technology     Hybrid Journal   (Followers: 1)
International Journal of Impact Engineering     Hybrid Journal   (Followers: 9)
International Journal of Information Acquisition     Hybrid Journal   (Followers: 1)
International Journal of Innovation and Applied Studies     Open Access   (Followers: 5)
International Journal of Innovation Science     Full-text available via subscription   (Followers: 9)
International Journal of Innovative Technology and Research     Open Access   (Followers: 1)
International Journal of Integrated Engineering     Open Access  
International Journal of Intelligent Engineering Informatics     Hybrid Journal  
International Journal of Intelligent Systems and Applications in Engineering     Open Access   (Followers: 2)
International Journal of Lifecycle Performance Engineering     Hybrid Journal   (Followers: 1)
International Journal of Machine Tools and Manufacture     Hybrid Journal   (Followers: 5)
International Journal of Manufacturing Research     Hybrid Journal   (Followers: 6)
International Journal of Manufacturing Technology and Management     Hybrid Journal   (Followers: 8)
International Journal of Materials and Product Technology     Hybrid Journal   (Followers: 4)
International Journal of Mathematical Education in Science and Technology     Hybrid Journal   (Followers: 8)
International Journal of Mathematics in Operational Research     Hybrid Journal  
International Journal of Medical Engineering and Informatics     Hybrid Journal   (Followers: 3)
International Journal of Micro Air Vehicles     Full-text available via subscription   (Followers: 7)
International Journal of Microwave Science and Technology     Open Access   (Followers: 4)
International Journal of Mobile Network Design and Innovation     Hybrid Journal   (Followers: 1)
International Journal of Multiphase Flow     Hybrid Journal   (Followers: 4)
International Journal of Nanomanufacturing     Hybrid Journal  
International Journal of Nanoscience     Hybrid Journal   (Followers: 2)
International Journal of Nanotechnology     Hybrid Journal   (Followers: 6)
International Journal of Nanotechnology and Molecular Computation     Full-text available via subscription   (Followers: 2)
International Journal of Navigation and Observation     Open Access   (Followers: 19)
International Journal of Network Management     Hybrid Journal   (Followers: 1)
International Journal of Nonlinear Sciences and Numerical Simulation     Hybrid Journal  
International Journal of Numerical Methods for Heat & Fluid Flow     Hybrid Journal   (Followers: 9)
International Journal of Optics     Open Access   (Followers: 6)
International Journal of Organisational Design and Engineering     Hybrid Journal   (Followers: 6)
International Journal of Pattern Recognition and Artificial Intelligence     Hybrid Journal   (Followers: 6)
International Journal of Pavement Engineering     Hybrid Journal   (Followers: 6)
International Journal of Physical Modelling in Geotechnics     Hybrid Journal   (Followers: 4)
International Journal of Plasticity     Hybrid Journal   (Followers: 6)
International Journal of Plastics Technology     Hybrid Journal   (Followers: 1)
International Journal of Polymer Analysis and Characterization     Hybrid Journal   (Followers: 6)
International Journal of Polymer Science     Open Access   (Followers: 22)
International Journal of Precision Engineering and Manufacturing     Hybrid Journal   (Followers: 8)
International Journal of Precision Engineering and Manufacturing-Green Technology     Hybrid Journal  
International Journal of Precision Technology     Hybrid Journal  
International Journal of Pressure Vessels and Piping     Hybrid Journal   (Followers: 17)
International Journal of Production Economics     Hybrid Journal   (Followers: 13)
International Journal of Quality and Innovation     Hybrid Journal   (Followers: 5)
International Journal of Quality Assurance in Engineering and Technology Education     Full-text available via subscription   (Followers: 3)
International Journal of Quality Engineering and Technology     Hybrid Journal   (Followers: 2)
International Journal of Quantum Information     Hybrid Journal   (Followers: 2)
International Journal of Rapid Manufacturing     Hybrid Journal   (Followers: 4)
International Journal of Recent Contributions from Engineering, Science & IT     Open Access   (Followers: 1)
International Journal of Reliability, Quality and Safety Engineering     Hybrid Journal   (Followers: 11)
International Journal of Renewable Energy Technology     Hybrid Journal   (Followers: 9)
International Journal of Robust and Nonlinear Control     Hybrid Journal   (Followers: 4)
International Journal of Science Engineering and Advance Technology     Open Access  
International Journal of Sediment Research     Full-text available via subscription   (Followers: 3)
International Journal of Self-Propagating High-Temperature Synthesis     Hybrid Journal   (Followers: 2)
International Journal of Service Science, Management, Engineering, and Technology     Full-text available via subscription   (Followers: 1)
International Journal of Signal and Imaging Systems Engineering     Hybrid Journal  
International Journal of Six Sigma and Competitive Advantage     Hybrid Journal   (Followers: 2)
International Journal of Social Robotics     Hybrid Journal   (Followers: 2)
International Journal of Software Engineering and Knowledge Engineering     Hybrid Journal   (Followers: 4)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 4)
International Journal of Speech Technology     Hybrid Journal   (Followers: 8)
International Journal of Spray and Combustion Dynamics     Full-text available via subscription   (Followers: 12)
International Journal of Surface Engineering and Interdisciplinary Materials Science     Full-text available via subscription   (Followers: 1)
International Journal of Surface Science and Engineering     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Engineering     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Manufacturing     Hybrid Journal   (Followers: 5)
International Journal of Systems and Service-Oriented Engineering     Full-text available via subscription  
International Journal of Systems Assurance Engineering and Management     Hybrid Journal  
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 4)
International Journal of Technoethics     Full-text available via subscription   (Followers: 1)
International Journal of Technology Management and Sustainable Development     Hybrid Journal   (Followers: 1)
International Journal of Technology Policy and Law     Hybrid Journal   (Followers: 6)
International Journal of Telemedicine and Applications     Open Access   (Followers: 3)
International Journal of Thermal Sciences     Hybrid Journal   (Followers: 13)
International Journal of Thermodynamics     Open Access   (Followers: 8)
International Journal of Turbo & Jet-Engines     Hybrid Journal   (Followers: 3)
International Journal of Ultra Wideband Communications and Systems     Hybrid Journal  
International Journal of Vehicle Autonomous Systems     Hybrid Journal  
International Journal of Vehicle Design     Hybrid Journal   (Followers: 6)
International Journal of Vehicle Information and Communication Systems     Hybrid Journal   (Followers: 2)
International Journal of Vehicle Noise and Vibration     Hybrid Journal   (Followers: 4)
International Journal of Vehicle Safety     Hybrid Journal   (Followers: 6)
International Journal of Vehicular Technology     Open Access   (Followers: 4)
International Journal of Virtual Technology and Multimedia     Hybrid Journal   (Followers: 3)
International Journal of Wavelets, Multiresolution and Information Processing     Hybrid Journal   (Followers: 1)
International Journal on Artificial Intelligence Tools     Hybrid Journal   (Followers: 6)
International Nano Letters     Open Access   (Followers: 6)

  First | 1 2 3 4 5 6 | Last

Journal Cover Engineering Analysis with Boundary Elements
  [SJR: 1.251]   [H-I: 52]   [1 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0955-7997
   Published by Elsevier Homepage  [3039 journals]
  • Evaluation of nearly singular integrals in isogeometric boundary element
           method
    • Abstract: Publication date: February 2017
      Source:Engineering Analysis with Boundary Elements, Volume 75
      Author(s): Y.P. Gong, C.Y. Dong, Y. Bai
      Isogeometric boundary element method (IGBEM) is a new numerical method that has received a lot of attentions in recent years. However, nearly singular integrals in the IGBEM have not yet received more attention when the IGBEM is used to study thin-body/coating structures. In this paper, the exponential transformation method based on the idea of diminishing the difference of the orders or the scale of change of addition factors in the denominator of the kernels is used to remove or weaken the near singularities of nearly singular integrals appearing in 2D/3D potential problems. Numerical results show that the present method is effective, stable and competitive. We believe that this work clearly presents the power of the IGBEM and provides an efficient approach to investigate the boundary layer effect appearing in thin-body/coating structures.

      PubDate: 2016-11-26T12:03:15Z
       
  • Studying normal perforation of monolithic and layered steel targets by
           conical projectiles with SPH simulation and analytical method
    • Abstract: Publication date: February 2017
      Source:Engineering Analysis with Boundary Elements, Volume 75
      Author(s): Yihua Xiao, Huanghuang Dong, Jianmin Zhou, Jungang Wang
      The normal perforation of monolithic and layered Weldox 460 E steel targets by conical projectiles is investigated with smoothed particle hydrodynamics (SPH) simulation and analytical method. A series of SPH simulations are performed for the perforation of monolithic targets with different thicknesses and layered targets with different total thicknesses and layering schemes. According to the simulated results, an empirical relation between ballistic limit velocity and target thickness is determined for monolithic target, and the variation of ballistic resistance with number of layers, total thickness and thickness configuration is revealed for layered target. Based on the established empirical relation for monolithic target, an analytical method is used to analyze the ballistic resistance of layered targets with different total thicknesses and layering schemes. The analytical results are compared with SPH simulation results, and the applicability and accuracy of the analytical method for the present problems are discussed.

      PubDate: 2016-11-20T00:21:44Z
       
  • Line integration method for treatment of domain integrals in 3D boundary
           element method for potential and elasticity problems
    • Abstract: Publication date: February 2017
      Source:Engineering Analysis with Boundary Elements, Volume 75
      Author(s): Qiao Wang, Wei Zhou, Yonggang Cheng, Gang Ma, Xiaolin Chang
      A line integration method is presented in this paper for evaluation of domain integrals in 3D problems. The method is a boundary-only discretization method and the domain integrals can be computed by sum of integrals on one-dimensional straight lines. Divergence theorem is used to transform the domain integrals into boundary integrals with one-dimensional integrals. The boundary integrals can be evaluated by boundary elements with integral points. Each integral point can be used to construct an integral line, and the domain integrals can be finally computed by line integrals on integral lines. Only the boundary discretization is needed and background cells are used to cut the integral lines into sub-lines to obtain the desired accuracy. The method is proved and applied in boundary element method for 3D potential and elasticity problems. Numerical examples have demonstrated the accuracy of the proposed method.

      PubDate: 2016-11-20T00:21:44Z
       
  • Compact approximation stencils based on integrated flat radial basis
           functions
    • Abstract: Publication date: January 2017
      Source:Engineering Analysis with Boundary Elements, Volume 74
      Author(s): N. Mai-Duy, T.T.V. Le, C.M.T. Tien, D. Ngo-Cong, T. Tran-Cong
      This paper presents improved ways of constructing compact integrated radial basis function (CIRBF) stencils, based on extended precision, definite integrals, higher-order IRBFs and minimum number of derivative equations, to enhance their performance over large values of the RBF width. The proposed approaches are numerically verified through second-order linear differential equations in one and two variables. Significant improvements in the matrix condition number, solution accuracy and convergence rate with grid refinement over the usual approaches are achieved.

      PubDate: 2016-11-12T23:48:09Z
       
  • Global error analysis of two-dimensional panel methods for dirichlet
           formulation
    • Abstract: Publication date: January 2017
      Source:Engineering Analysis with Boundary Elements, Volume 74
      Author(s): José M. Ezquerro, Ana Laverón-Simavilla, Victoria Lapuerta, Jeff Porter
      A rigorous analytical study of the global error of panel methods is presented. The analysis is performed for a wide variety of body shapes and different panel geometries to fully understand their effect on the convergence of the method. In particular, we study the global error associated with panel methods applied to thin or thick bodies with purely convex parts or with both convex and concave parts, and with smooth or non-smooth boundaries. Most previous studies focused on the analysis of local error, considering only the influence of the nearest panels and excluding the rest. The difference is shown to be appreciable in many configurations. Generally, there is a lack of consensus concerning the order of magnitude of the error for panel methods even in the simplest case with flat panels and a constant distribution of doublets along them. This paper clarifies apparently different or inconsistent results obtained by other authors.

      PubDate: 2016-11-12T23:48:09Z
       
  • Boundary element analysis of bar silencers using the scattering matrix
           with two-dimensional finite element modes
    • Abstract: Publication date: January 2017
      Source:Engineering Analysis with Boundary Elements, Volume 74
      Author(s): L. Yang, P. Wang, T.W. Wu
      Bar silencers used in industry may consist of a large array of rectangular or round bars packed in a rectangular lattice arrangement. Due to the size of the lattice, normally only a single unit that represents a building block for the lattice is isolated for analysis purposes. Even with one isolated unit, the inlet and the outlet are still quite large, and the plane-wave cutoff frequency can be very low. Therefore, higher-order modes must be considered at the inlet and outlet in order to calculate the transmission loss. This paper uses the recently developed “impedance-to-scattering matrix method” to convert the element-based impedance matrix into the mode-based scattering matrix for transmission loss calculation. Depending on the shape of the inlet and outlet, it may not always be possible to find an analytical expression of the modes needed for the modal expansion. In this paper, the two-dimensional finite element method is used to extract the eigenvalues and the eigenvectors of the inlet/outlet cross section. The eigenvectors are then used in the modal expansion to convert the impedance matrix into the scattering matrix. Test cases include several commonly used inlet and outlet configurations, such as rectangular, circular and triangular cross sections.

      PubDate: 2016-11-12T23:48:09Z
       
  • Numerical solution of a non-classical two-phase Stefan problem via radial
           basis function (RBF) collocation methods
    • Abstract: Publication date: November 2016
      Source:Engineering Analysis with Boundary Elements, Volume 72
      Author(s): Mehdi Dehghan, Mahboubeh Najafi
      The aim of this paper is to make a comparative study of some high order methods for the numerical solution of a non-classical one-dimensional two-phase Stefan problem. The moving boundary is captured explicitly via boundary immobilization method. The Chebyshev and Legendre spectral collocation methods as high order mesh-based techniques and some radial basis function (RBF) collocation techniques as high order meshless methods are used for spatial discretization. The considered Stefan problem has two stages: one before the extinction time ( 0 ≤ t ≤ t m ) and one after the extinction time ( t m ≤ t ) . For this particular model there exists a closed form solution for the former stage but there is no analytical solution for the latter one. Numerical results show that RBF-QR method can attain the accuracy of spectral methods when implemented on Chebyshev grid. The high order accuracy for the two stages shows the superiority of the proposed methods in comparison to the previous works.

      PubDate: 2016-11-06T23:18:28Z
       
  • Implementation of CPCT based BIEs for 3D elasticity and its application in
           fracture mechanics
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Jia-He Lv, Xia-Ting Feng, Fei Yan, Bing-Rui Chen
      The accurate evaluation of singular boundary integrals is a long-debated issue for the successful implementation of BIEs. In the past decades, various methods have been developed, among which the singularity subtraction technique (SST) has been proved to be a unified method for various orders of singularities. However, the accuracy of original SST is sensitive to element shape due to the near singularity caused by element shape distortion. In this paper, a new conformal polar coordinate transformation (CPCT) for quadrilateral elements is proposed to eliminate the shape effect. Besides, an improved sigmoidal transformation is introduced in the angular direction to assign Gauss points more reasonably. By combination of the two strategies with original SST, a more efficient and robust numerical integration scheme for singular integrals can be obtained. Several numerical examples including crack problems are presented to demonstrate the accuracy and feasibility to coarse meshes for CPCT based BIEs and dual BEM.

      PubDate: 2016-11-06T23:18:28Z
       
  • Domain decomposition scheme with equivalence spheres for the analysis of
           aircraft arrays in a large-scale range
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): Ting Su, Mengmeng Li, Rushan Chen
      we propose a domain decomposition scheme for solving scattering problem from multi-objects distribution in a large-scale range. Each sub-object is enclosed by an equivalence sphere. The scheme is composed of the equivalence process and translation process. In the equivalence process, the scattering fields from the sub-object are produced by the equivalence mode currents on the equivalence sphere. The equivalence mode currents are the current expansion of the body of revolution (BoR) basis functions, which are transformed from the current expansion of the Rao–Wilton-Glisson (RWG) basis functions. The multilevel fast multipole algorithm (MLFMA) is employed to accelerate the equivalence process. In the translation process, the mode translation matrices are obtained based on the BoR basis functions and the coordinate conversion method for computing the interactions among the equivalence spheres. The adaptive cross algorithm (ACA) is used to accelerate the evaluation of mode translation matrices. The proposed approach is very efficient for analysis of the objects distributed in a large-scale range. Numerical results demonstrate that the approach provides significant improvements in terms of memory requirements.

      PubDate: 2016-11-06T23:18:28Z
       
  • Forced vibration analysis of functionally graded beams by the meshfree
           boundary-domain integral equation method
    • Abstract: Publication date: November 2016
      Source:Engineering Analysis with Boundary Elements, Volume 72
      Author(s): Y. Yang, C.C. Lam, K.P. Kou
      Forced vibration of two-dimensional functionally graded beams is studied in this paper by a developed meshfree boundary-domain integral equation method. Material properties of the functionally graded beams are assumed varying continuously either in longitudinal or transvers direction following the exponential function. The boundary-domain integral equations are derived by using the elastostatic fundamental solutions based on the two-dimensional elastic theory. Radial integral method (RIM) is employed to transform the domain integrals into boundary integrals. A meshfree scheme is achieved through assuming the displacements and accelerations in the domain integrals by a combination of the radial basis function and polynomials with time dependent coefficients. Wilson-θ, Houbolt as well as two kinds of damped Newmark's algorithms are applied to accomplish the time integration. The forced vibration of the functionally graded beam subjected by the harmonic loading and transient loading are investigated in detail. Numerical examples demonstrate that the four mentioned time integral schemes are all adapted well to the developed meshfree boundary-domain integral equation method for analyzing the forced vibration of homogeneous structures. For the analysis of FG structures, it is shown that the damped Newmark's algorithm can achieve more stable and accurate results.

      PubDate: 2016-11-06T23:18:28Z
       
  • Complete solutions at or near the boundary nodes of boundary elements for
           coupled stretching-bending analysis
    • Abstract: Publication date: November 2016
      Source:Engineering Analysis with Boundary Elements, Volume 72
      Author(s): H.W. Chang, Chyanbin Hwu
      In boundary element analysis if the field point is located at or near the boundary nodes, its associated integrals may become singular. Although in the literature the displacements and tractions at the boundary nodes have been well solved for the coupled stretching-bending analysis, their related strains and stresses still remain unsolved due to the coincidence of field points and boundary nodes. In this paper to avoid the singular problem, at the boundary nodes the components of stress resultants, bending moments, in-plane strains and plate curvatures in the tangential direction are approximated by finite difference method, whereas the components in normal direction are evaluated with the aid of constitutive laws for the tangential-normal coordinate. After getting the complete solutions at the boundary nodes, the solutions for the points near the boundary are interpolated by the moving least square method. To verify the correctness of the proposed method, examples of the laminated plates with or without holes subjected to in-plane tension, or out-of-plane bending, or transverse loading are illustrated and compared with the solutions obtained by the other methods.

      PubDate: 2016-11-06T23:18:28Z
       
  • A fully smoothed finite element method for analysis of axisymmetric
           problems
    • Abstract: Publication date: November 2016
      Source:Engineering Analysis with Boundary Elements, Volume 72
      Author(s): Detao Wan, Dean Hu, Gang Yang, Ting Long
      A fully smoothed finite element method is developed to model axisymmetric problems by incorporating a special integral into the Cell-based, Node-based and Edge-based Smoothed Finite Element Method (CS-FEM, NS-FEM, ES-FEM), respectively. The special integral is done by combining Gauss divergence theorem with the evaluation of an indefinite integral, which can be used for treatment of the axisymmetric term in strain matrix and shape function in mass matrix. Applying the special integral and smoothing technique, all the domain integrals in stiffness matrix and mass matrix can be smoothed and rewritten as boundary integrals of smoothing cells. Then the stiffness matrix and mass matrix of element are computed by a simple summation over the smoothing cells. In this work, the proposed method is extended to static and structure dynamic analysis of axisymmetric problems. Numerical examples show that the proposed method can yield good performance even for extremely irregular elements.

      PubDate: 2016-11-06T23:18:28Z
       
  • Crack analysis by using the enriched singular boundary method
    • Abstract: Publication date: November 2016
      Source:Engineering Analysis with Boundary Elements, Volume 72
      Author(s): Ji Ma, Wen Chen, Ji Lin
      In this paper, we make the first attempt to extend the singular boundary method to crack problems in conjunction with the domain decomposition technique. In order to characterize singular behaviors around cracks, enriched functions are analytically derived from the governing equations and the corresponding conditions containing singularities. We verify the present enriched singular boundary method to the torsion problem of a cracked bar and the acoustic propagation problem in crack media, which are governed by Laplace and Helmholtz equations, respectively. Numerical results demonstrate the accuracy and efficiency of the proposed scheme.

      PubDate: 2016-11-06T23:18:28Z
       
  • Three-dimensional fracture propagation with numerical manifold method
    • Abstract: Publication date: November 2016
      Source:Engineering Analysis with Boundary Elements, Volume 72
      Author(s): Yongtao Yang, Xuhai Tang, Hong Zheng, Quansheng Liu, Lei He
      By introducing the concept of mathematical cover and physical cover, the numerical manifold method (NMM) is able to solve continuous and discontinuous problems in a unified way. In this paper, the NMM is developed to analyze three dimensional (3D) fracture propagation. The maximum tensile stress criterion is implemented to determine whether the fracture will propagate and the direction of fracture propagation. Three benchmark problems are analyzed to validate the present algorithm and program. The numerical results replicate available experimental results and existing numerical results. The present algorithm and 3D NMM code are promising for 3D fracture propagation. They deserve to be further developed for the analysis of rock mechanic problems in which the initiation and propagation of multiple fractures, tensile and shear fractures, and fracture propagation under compressive loading are taken into account.

      PubDate: 2016-11-06T23:18:28Z
       
  • More accurate results for nonlinear generalized
           Benjamin-Bona-Mahony-Burgers (GBBMB) problem through spectral meshless
           radial point interpolation (SMRPI)
    • Abstract: Publication date: November 2016
      Source:Engineering Analysis with Boundary Elements, Volume 72
      Author(s): Elyas Shivanian, Ahmad Jafarabadi
      In this article, the spectral meshless radial point interpolation (SMRPI) technique is applied to the nonlinear generalized Benjamin-Bona-Mahony-Burgers (GBBMB) in two-dimension with initial and Dirichlet-type boundary conditions. This method is based on erudite combination of meshless methods and spectral collocation techniques. The point interpolation method with the help of radial basis functions is used to construct shape functions which play as basis functions in the frame of SMRPI. To treat the nonlinearity part, a kind of predictor-corrector scheme combined with Crank-Nicolson technique is adopted. We prove that the time discrete scheme is stable respect to the time variable in H 1 and convergent with convergence order O ( δ t ) . To show the high accuracy of SMRPI, a comparison study of the present method and recently applied interpolating element-free Galerkin technique is given through applying on GBBMB equation. The results reveal that the method is more accurate and possesses low complexity.

      PubDate: 2016-11-06T23:18:28Z
       
  • Analysis of underwater acoustic scattering problems using stable
           node-based smoothed finite element method
    • Abstract: Publication date: November 2016
      Source:Engineering Analysis with Boundary Elements, Volume 72
      Author(s): Yingbin Chai, Wei Li, Tianyun Li, Zhixiong Gong, Xiangyu You
      A stable node-based smoothed finite element method (SNS-FEM) is presented that cures the “overly-soft” property of the original node-based smoothed finite element method for the analysis of underwater acoustic scattering problems. In the SNS-FEM model, the node-based smoothed gradient field is enhanced by additional stabilization term related to the gradient variance items. It is demonstrated that SNS-FEM provides an ideal stiffness of the continuous system and improves the performance of the NS-FEM and FEM. In order to handle the acoustic scattering problems in unbounded domain, the well known Dirichlet-to-Neumann (DtN) boundary condition is combined with the present SNS-FEM to give a SNS-FEM-DtN model for exterior acoustic problems. Several numerical examples are investigated and the results show that the SNS-FEM-DtN model can achieve more accurate solutions compared to the NS-FEM and FEM.

      PubDate: 2016-11-06T23:18:28Z
       
  • Crack propagation in non-homogenous materials: Evaluation of mixed-mode
           SIFs, T-stress and kinking angle using a variant of EFG Method
    • Abstract: Publication date: November 2016
      Source:Engineering Analysis with Boundary Elements, Volume 72
      Author(s): N. Muthu, S.K. Maiti, B.G. Falzon, Wenyi Yan
      A new variant of the Element-Free Galerkin (EFG) method, that combines the diffraction method, to characterize the crack tip solution, and the Heaviside enrichment function for representing discontinuity due to a crack, has been used to model crack propagation through non-homogenous materials. In the case of interface crack propagation, the kink angle is predicted by applying the maximum tangential principal stress (MTPS) criterion in conjunction with consideration of the energy release rate (ERR). The MTPS criterion is applied to the crack tip stress field described by both the stress intensity factor (SIF) and the T-stress, which are extracted using the interaction integral method. The proposed EFG method has been developed and applied for 2D case studies involving a crack in an orthotropic material, crack along an interface and a crack terminating at a bi-material interface, under mechanical or thermal loading; this is done to demonstrate the advantages and efficiency of the proposed methodology. The computed SIFs, T-stress and the predicted interface crack kink angles are compared with existing results in the literature and are found to be in good agreement. An example of crack growth through a particle-reinforced composite materials, which may involve crack meandering around the particle, is reported.

      PubDate: 2016-11-06T23:18:28Z
       
  • A direct velocity-pressure coupling Meshless algorithm for incompressible
           fluid flow simulations
    • Abstract: Publication date: November 2016
      Source:Engineering Analysis with Boundary Elements, Volume 72
      Author(s): Andrés Vidal, Alain J. Kassab, Eduardo A. Divo
      A localized radial-basis function (RBF) Meshless algorithm, with a direct velocity-pressure coupling scheme, is presented for fluid flow simulations. The proposed method is a combination of several efficient techniques found in different Computational Fluid Dynamic (CFD) procedures and has very low numerical diffusion. The fundamental idea of this method lays on several important inconsistencies found in three of the most popular techniques used in CFD, segregated procedures, streamline-vorticity formulation for 2D viscous flows, and the fractional-step method, very popular in Direct Numerical Simulation (DNS) and Large-Eddy Simulation (LES). The proposed scheme uses the classical segregated point distribution for all primitive variables, and performs all necessary interpolations with the accurate RBF technique. The viscous term is estimated using standard second order finite differences, while the convection term is discretized using the low-diffusion flux limiters. The velocity-pressure coupling is performed with the flow equations in their original form, and using a direct velocity-pressure coupling scheme. This way of solving the flow equations has no approximations in the boundary conditions. The method is validated with the 2D lid-driven cavity problem and very good agreement is found with classical data.

      PubDate: 2016-11-06T23:18:28Z
       
  • Numerical investigation on seakeeping performance of SWATH with Three
           Dimensional Translating-pulsating Source Green Function
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): X.S. Sun, C.B. Yao, Q. Ye
      The seakeeping performance of Small Waterplane Area Twin Hull (SWATH) was investigated by the boundary element method based on the Three Dimensional Translating-pulsating Source Green Function (3DTP). Some factors that differ from conventional monohull ships, but may have great influence on SWATH were included in the equations of motion, namely the hydrodynamic interaction between the twin hulls, the viscous damping and the effect of stabilizing fins. Numerical simulations have been carried out to predict the wave loads and motions of several SWATH vehicles. The present method has been validated by comparison with both the strip theory formulation (STF) method and the experiment. The result indicates that the predictions of heave responses from both numerical methods agrees well with that of the experiment at different forward speed, while the discrepancies between numerical methods and the experiment are much more pronounced at pitch motions. Generally, the motions are better predicted by the present method based on 3DTP than by the STF method, particularly for pitch motion.

      PubDate: 2016-11-06T23:18:28Z
       
  • Boundary-integral-based process for calculating stiffness matrices of
           space frame elements with axially varying cross section
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): F.C. de Araujo, R.A.T. Pereira
      In this paper, the geometric cross-section properties needed for constructing stiffness matrices of 3D (space) frame elements are determined by means of formulations purely based on boundary integrals. In the strategy, the torsional constant and torsion center are calculated by applying the Boundary Element Method (BEM), wherein for modeling thin-wall cross-sections, specific integration algorithms are devised to evaluate the nearly-singular integrals involved. For the other section properties as e.g. area, 1st and 2nd moments of area, and the shear form factors, Green's theorem is employed to express them in terms of boundary integrals, and the existing boundary-element meshes, used for determining the torsion constant, is employed to calculate the corresponding boundary integrals. In the applications, space frame elements with geometrically complex cross-sections varying along their axis are considered.

      PubDate: 2016-11-06T23:18:28Z
       
  • A finite element/generalized finite element code-coupling approach for
           linear elastic fracture mechanics problems
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): Mohammad Malekan, Felício B. Barros, Roque L.S. Pitangueira
      This paper presents a procedure for the coupling of a Generalized Finite Element (GFE) code and a commercial Finite Element (FE) package to solve a linear elastic fracture mechanics problem. The code coupling process consists of a GFE code embedded into the computational platform INSANE (INteractive Structural ANalysis Environment) with the commercial FE package ABAQUS for coupled FE/GFE analyses. The problem domain is decomposed into two sub-domains: FE domain (safe domain) and GFE domain (crack domain). Theoretical background information is provided on the GFEM and the stress intensity factors computation. Main steps of the coupling procedure are explained and necessary information is provided. The results show that the coupling procedure is able to capture the stress and displacement fields quite accurate. Details of the implementation are presented and important aspects of using this procedure are highlighted in the numerical example.

      PubDate: 2016-11-06T23:18:28Z
       
  • Impedance-to-scattering matrix method for large silencer analysis using
           direct collocation
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): P. Wang, T.W. Wu
      Large silencers used in industry usually have a very large cross section at the inlet and outlet. Higher-order modes will populate the inlet and outlet even at very low frequencies. A three-dimensional analysis tool, such as the finite element method or the boundary element method, must incorporate certain forms of modal expansion in order to consider the higher-order modes in the transmission loss computation. In this paper, the impedance matrix obtained from the sub-structured boundary element method is converted into the scattering matrix that relates the higher-order modes. Since there are always more boundary elements at the inlet and outlet than the total number of propagating modes, a least-squares procedure is used to convert the element-based impedance matrix into the modal expansion-based scattering matrix. The transmission loss of the silencer can then be computed from the scattering matrix if a certain form of the incident wave is assumed. Furthermore, a slightly rearranged form of the scattering matrix may also be used to combine subsystems in series connection.

      PubDate: 2016-11-06T23:18:28Z
       
  • A new direct time integration method for the semi-discrete parabolic
           equations
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): John T. Katsikadelis
      A direct time integration method is presented for the solution of systems of first order ordinary differential equations, which represent semi-discrete diffusion equations. The proposed method is based on the principle of the analog equation, which converts the N coupled equations into a set of N single term uncoupled first order ordinary differential equations under fictitious sources. The solution is obtained from the integral representation of the solution of the substitute single term equations. The stability and convergence of the numerical scheme is proved. The method is simple to implement. It is self-starting, unconditionally stable, accurate, while it does not exhibit numerical damping. The stability does not demand symmetrical and positive definite coefficient matrices. This is an important advantage, since the scheme can solve semi-discrete diffusion equations resulting from methods that do not produce symmetrical matrices, e.g. the boundary element method. The method applies also to equations with variable coefficients as well as to nonlinear ones. It performs well when long time durations are considered and it can be used as a practical method for integration of stiff parabolic equations in cases where widely used methods may fail. Numerical examples, including linear as well as non linear systems, are treated by the proposed method and its efficiency and accuracy are demonstrated.

      PubDate: 2016-11-06T23:18:28Z
       
  • New treatment of the self-weight and the inertial effects of rotation for
           the BEM formulation of 2D anisotropic solids
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): Y.C. Shiah, Shang-Yu Ye
      As an evident drawback for using the conventional boundary element method (BEM), an extra domain integral is present in the boundary integral equation when body-force effects are involved. For 2D anisotropic elastostatics, the extra domain integral has been exactly transformed to the boundary; however, an additional line integral intersecting the domain is involved for general cases to make the transformation. For a multiply connected region, this process is quite involving and computation-wise inefficient indeed, especially when its geometry is very complicated. In this article, a new approach is proposed to make the transformation, yet without involving extra line integrals. By this approach, the BEM's notion as a boundary solution technique is completely restored. In the end, a few benchmark problems are studied to demonstrate the veracity of formulations as well as our successful implementation in an existing BEM code.

      PubDate: 2016-11-06T23:18:28Z
       
  • Explicit empirical formula evaluating original intensity factors of
           singular boundary method for potential and Helmholtz problems
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): Junpu Li, Wen Chen, Zhuojia Fu, Linlin Sun
      This short communication proposes two new explicit empirical formulas to determine the original intensity factors on Neumann and Dirichlet boundary in the singular boundary method (SBM) solution of 2D and 3D potential and Helmholtz problems. Without numerical integration and subtracting and adding-back technique, the original intensity factors can be obtained directly by implementing the proposed explicit empirical formulas. The numerical investigations show that the SBM with these new explicit empirical formulas can provide the accurate solutions of several benchmark examples in comparison with the analytical, Boundary element method (BEM) and Regularized meshless method (RMM) solutions. In most cases, the present SBM with empirical formulas yields the similar numerical accuracy as the BEM and the SBM in which the original intensity factors are evaluated by the other time-consuming approaches. It is worthy of noting that the empirical formula costs far less CPU and storage requirements at the same number of boundary nodes and performs more stably than the inverse interpolation technique in the SBM.

      PubDate: 2016-11-06T23:18:28Z
       
  • Weak-form collocation – A local meshless method in linear elasticity
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): T. Oliveira, A. Portela
      This paper is concerned with the formulation of local meshfree methods, for the solution of two-dimensional problems in linear elasticity, in the framework of the theory of structures. Local meshfree methods are derived through a weighted-residual formulation which leads to a local weak form that is the well known work theorem of the theory of structures. In an arbitrary local region, the work theorem establishes an energy relationship between a statically-admissible stress field and an independent kinematically-admissible strain field. Based on the independence of these two fields, this paper presents two new meshless formulations that aim a reduction of the computational effort. While in the first formulation the local form of the work theorem is reduced to regular boundary terms only, in the second formulation the local form of the work theorem is simply an integration-free formula. The moving least squares (MLS) approximation of the elastic field is used in this paper to implement both local meshless formulations. Several problems were analyzed with these techniques, in order to assess the accuracy and efficiency of the formulations. The results obtained in this work are in perfect agreement with those of the available analytical solutions. The accuracy and efficiency of the integration-free formulation make this a reliable and robust local meshfree method, generated in the framework of the theory of structures.

      PubDate: 2016-11-06T23:18:28Z
       
  • Three-dimensional BEM analysis of stress state near a crack-borehole
           system
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): Dmitry V. Nikolskiy, Mattia Zammarchi, Sofia G. Mogilevskaya, Alberto Salvadori
      The paper presents a numerical study of the three-dimensional problem of cracks interacting with a cylindrical uniformly pressurized borehole. The theoretical developments describe general case in which the axis of the borehole can be inclined to the vertical direction, the cracks are either located outside of the borehole or emanate from it, and the in-situ stresses are uniform with major principal stress acting in vertical direction. The tractions are prescribed at the cracks surfaces that includes two limiting cases of traction-free cracks (“fast pressurization”) or cracks subjected to uniform load equal to that applied at the surface of the borehole (“slow pressurization”). The study is based on the complex integral representations for the three-dimensional fields around the borehole-crack system. The boundary surfaces are approximated using triangular mesh and quadratic polynomials are employed for approximating the boundary unknowns. The prescribed boundary conditions are met using “limit after discretization” procedure. The linear algebraic system to find the unknowns is set up by the collocation method. Two numerical benchmarks are presented.

      PubDate: 2016-11-06T23:18:28Z
       
  • Dynamic pressure distributions of semi-submersible
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): Ke Wang, Xiaowei Gao, Xiaoming Cheng
      In the hydrodynamic study of Semi-submersibles, the wave pressure distribution on the wetted surface is critical input for structure analysis. Based on wave radiation and diffraction theory, a higher-order boundary element method (HOBEM) was applied to calculate the wave pressure distribution for a semi-submersible under specified wave direction and frequency. An integral system containing the FEM modeling of the semi-submersible, numerical calculation of hydrodynamic motion coefficients and data extraction and export for BEM analysis was established in the current study. A newly developed multiple and double nodes relocation method coupled with FEM-BEM model transformation is applied to remove the singularities along the sharp edges and corners of the semi-submersible. The numerical results confirm that the above algorithm significantly improves the numerical accuracy of wave pressure analysis for the semi-submersible.

      PubDate: 2016-11-06T23:18:28Z
       
  • A piecewise partitioning Scaled Boundary Finite Element algorithm to solve
           viscoelastic problems with cyclic symmetry
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): Chongshuai Wang, Yiqian He, Haitian Yang
      Scaled Boundary Finite Element Method (SBFEM) and a temporally adaptive algorithm are combined to solve viscoelastic problems. By expanding variables at a discretized time interval, a spatially and temporally coupled viscoelastic problem is decoupled into a series of recursive spatial problems, which are solved by SBFEM, the computing accuracy in the time domain is controlled via a self-adaptive process. For the cyclic symmetric structures, the cyclic symmetry is exploited to reduce the computational expense of SBFEM, both the eigenvalue and system equations of SBFEM are partitioned into a number of smaller independent problems, which are solved by a partitioning algorithm. Two numerical examples are given to verify and illustrate the proposed approach.

      PubDate: 2016-11-06T23:18:28Z
       
  • Flows in slip-patterned micro-channels using boundary element methods
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): Chandra Shekhar Nishad, Anirban Chandra, G.P. Raja Sekhar
      In this study we investigate steady, pressure-driven, two-dimensional flow of Newtonian fluid through slip-patterned, rectangular channels in the low Reynolds number limit. The slip flow regime is modeled using the Navier's slip boundary condition. In this work, we present only in-phase patterned slip. Subsequently, based on the characteristic length of the patterning, we have considered two subcases, namely large and fine patterned slip. Boundary element method (BEM) is used to numerically solve Stokes equation and obtain the streamline profiles. Streamlines, velocity profiles, pressure gradients, and shear stresses are analyzed to gain a proper understanding of the flow mechanics.

      PubDate: 2016-11-06T23:18:28Z
       
  • A generalized beta finite element method with coupled smoothing techniques
           for solid mechanics
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): W. Zeng, G.R. Liu, C. Jiang, T. Nguyen-Thoi, Y. Jiang
      This paper presents a generalized smoothing techniques based beta finite element method (βFEM) to improve the performance of standard FEM and the existing smoothed finite element methods (S-FEM) in solid mechanics. As we know, the edge-based (for 2D) or face-based (for 3D) strain smoothing techniques can bring much more accurate solutions than standard FEM, and offer lower bounds for force driven problems. The node-based smoothing technique with “overly-soft” feature, on the other hand has a unique property of producing upper bound solutions. This work proposes a novel generalized S-FEM with the smoothing domains generated based on both edges/faces and nodes. An adjustable parameter β is introduced to control the ratio of the area of edge/face-based and node-based smoothing domains. It is found that nearly exact solutions in strain energy can be obtained by tuning the parameter, making use of the important property that the exact solution is bonded by the solutions of NS-FEM and ES/FS-FEM. Standard patch tests are likewise satisfied. A number of numerical examples (static, dynamic, linear and nonlinear) have shown that the present βFEM method is found to be ultra-accurate, insensitive to mesh quality, temporal stable, capable of modeling complex geometry, immune from volumetric locking, etc.

      PubDate: 2016-11-06T23:18:28Z
       
  • Heat conduction analysis by adaptive iterative BEM-FEM coupling procedures
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): D. Soares, L. Godinho
      This work explores the application of coupled numerical models in thermal conduction analysis, taking into account frequency domain formulations. For this purpose, iterative coupling techniques between the Boundary Element Method (BEM) and the Finite Element Method (FEM) are discussed, also considering adaptive discretization procedures. Two coupling approaches are studied here, both using optimal relaxation parameters to ensure and/or to speed up the convergence of the iterative analysis. Non-matching discretizations on the common interfaces of the different subdomains of the model are allowed, and a single iterative cycle is adopted, incorporating both the adaptive and the coupling processes simultaneously. The methodology is quite flexible, and the possibility of using independent discretizations on each subdomain greatly facilitates the use of enhanced adaptive remeshing; in this context, specialized adaptive techniques for each subdomain/methodology may be applied. The adoption of a single iterative loop also renders a very efficient methodology, avoiding the excessive computational costs of sequentially chained iterative cycles. Numerical examples are presented in the end of the paper, illustrating the good performance of the proposed techniques, as well as their potentialities in engineering applications.

      PubDate: 2016-11-06T23:18:28Z
       
  • Automated hybrid singularity superposition and anchored grid pattern BEM
           algorithm for the solution of inverse geometric problems
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): Marcus W. Ni, Alain J. Kassab, Eduardo Divo
      A method for solving an inverse geometric problem is presented by reconstructing the unknown subsurface cavity geometry with the boundary element method (BEM) and a genetic algorithm in combination with the Nelder-Mead non-linear simplex optimization method. The heat conduction problem is solved by the BEM which calculates the difference between the measured temperature at the exposed surface and the computed temperature under the current update of the unknown subsurface flaws and cavities. In a first step, clusters of singularities are utilized to solve the inverse problem and to identify the location of the centroid(s) of the subsurface cavity(ies)/flaw(s). In a second step, the reconstruction of the estimated cavity(ies)/flaw(s) geometry(ies) is accomplished by utilizing an anchored grid pattern upon which cubic spline knots are restricted to move in the search for the unknown geometry. The solution is achieved using a genetic algorithm accelerated with the Nelder-Mead non-linear simplex method. The automated algorithm successfully reconstructs single and multiple subsurface cavities within two dimensional mediums. The cavity detection was enhanced by applying multiple boundary condition sets (MBCS) to the same geometry. This extra information supplied on the boundary made the subsurface cavity easily detectable despite its low heat signature effect on the boundaries.

      PubDate: 2016-11-06T23:18:28Z
       
  • A new dual reciprocity hybrid boundary node method based on Shepard and
           Taylor interpolation method and Chebyshev polynomials
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): Fei Yan, Xia-Ting Feng, Jia-He Lv, Peng-Zhi Pan, Shao-Jun Li
      A new dual reciprocity hybrid boundary node method (DHBNM) is proposed in this paper, in which the Shepard and Taylor interpolation method (STIM) and Chebyshev polynomials interpolation are proposed. Firstly, the Shepard interpolation is used to construct zero level shape function, and the high-power shape functions are constructed through the Taylor expansion, and through those two methods, no inversion is needed in the whole process of the shape function construction. Besides, Chebyshev polynomials are used as the basis functions for particular solution interpolation instead of the conical function, radial basis functions, and the analytical solutions of the basic form of particular solutions related to Chebyshev polynomials for elasticity are obtained, by means of this method, no internal node is needed, and interpolation coefficients can be given as explicit functions, so no inversion is needed for particular solution interpolation, which costs a large amount of computational expense for the traditional method. Based on those two methods, a new dual reciprocity hybrid boundary node method is developed, compared to the traditional DHBNM, no inversion is needed for both shape function construction and particular solution interpolation, which greatly improves the computational efficiency, and no internal node is needed for particular solution interpolation. Numerical examples are given to illustrate that the present method is accurate and effective.

      PubDate: 2016-11-06T23:18:28Z
       
  • Mixed miscible-immiscible fluid flow modelling with incompressible SPH
           framework
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): Gourabananda Pahar, Anirban Dhar
      A divergence-free Incompressible Smoothed Particle Hydrodynamics (ISPH) framework is developed for modelling multifluid immiscible/miscible flows. The numerical model considers Navier-Stokes equation along with scalar-transport equation to represent flow characteristics. Pure divergence free ISPH algorithm is used to solve Navier-Stokes momentum equation. Scalar transport equation is solved based on the nature of the fluid particles represented in terms of colour indicator (ϕ). Fixed ghost particles are utilized for simulating slip boundary. Proposed model is validated against three analytical/experimental results: (a) immiscible Rayleigh-Taylor Instability (b) lock-exchange non-Boussinesq flow (c) miscible gravity current with low density ratio. The model can capture Kelvin-Helmholtz instabilities generated at the interface. the framework is capable of capturing density-dependent flow with low to high density ratio alike. The capability of the developed model in general multifluid system is demonstrated for two cases (a) miscible multimode Rayleigh-Taylor Instability and (b) mixed miscible-immiscible fluid flow simulation.

      PubDate: 2016-11-06T23:18:28Z
       
  • On deterministic-stochastic time domain study of dipole antenna for GPR
           applications
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): D. Poljak, S. Antonijevic, S. Sesnic, S. Lallechere, K. El Khamlichi Drissi
      A deterministic-stochastic transient study of Ground Penetrating Radar (GPR) dipole antenna radiating in a presence of a two-media configuration is carried out in the paper. A deterministic direct time domain formulation is based on the corresponding space-time Hallen integral equation. The numerical solution is carried out via the improved space-time variant of the Galerkin-Bubnov Indirect Boundary Element Method (GB-IBEM). The Stochastic-Collocation (SC) method is then applied to determine accurate confidence intervals due to the random variations of GPR input parameters. Once obtaining the current along the dipole antenna, it is possible to calculate other parameters of interest for GPR dipole antenna behavior, such as the field reflected from the interface of two media, or the field transmitted into a lower half-space. Some illustrative numerical results for the transient current along the dipole antenna and transient electric field transmitted into the lower half-space are given.

      PubDate: 2016-11-06T23:18:28Z
       
  • Using the Gaussian function to simulate constant potential anodes in
           multiobjective optimization of cathodic protection systems
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): W.J. Santos, J.A.F. Santiago, J.C.F. Telles
      The purpose of this work is to numerically find the optimum location of constant potential anodes to ensure complete structure surface protection using a cathodic protection technique. The existence of sacrificial anodes is originally introduced through the boundary conditions of the corresponding boundary value problem (BVP). However, if constant potential galvanic regions are introduced through its boundaries, then finding their optimal location is not an easy task due to the necessity of redefining boundary geometric nodes and the arrangement of virtual sources for the standard method of fundamental solutions (MFS) formulation. Therefore, in this work, the galvanic anodes are introduced as source terms using a Gaussian function. Hence, the boundary remains the same for different anode positions. The optimization process includes the identification of the following parameters characterizing the Gaussian function: the optimum coordinates of the centre of the anode, a factor that involves the inherent potential of the electrode and a proportionality factor for the electrode diameter. The MFS methodology coupled with a genetic algorithm presented good results for this multiobjective optimization procedure. This fact can be seen in the several results of applications that are discussed in this paper, considering numerical simulations in finite regions in R 2.

      PubDate: 2016-11-06T23:18:28Z
       
  • Direct meshless local Petrov–Galerkin method for the two-dimensional
           Klein–Gordon equation
    • Abstract: Publication date: January 2017
      Source:Engineering Analysis with Boundary Elements, Volume 74
      Author(s): Mohammadreza Ahmadi Darani
      In this paper we apply the direct meshless local Petrov–Galerkin (DMLPG) method to solve the two dimensional Klein–Gordon equations in both strong and weak forms. Low computational cost is the main property of this method compared with the original MLPG technique. The reason lies behind the approach of generalized moving least squares approximation where the discretized functionals, obtained from the PDE problem, are directly approximated from nodal values. This shifts the integration over polynomials rather than the MLS shape functions, leading to an extremely faster scheme. We will see that this method can successfully solve the problem with a reasonable accuracy.

      PubDate: 2016-11-06T23:18:28Z
       
  • Analysis of the inherent instability of the interpolating moving least
           squares method when using improper polynomial bases
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): Xiaolin Li, Qingqing Wang
      This paper first discusses the inherent instability of the interpolating moving least squares (IMLS) method. In the original IMLS method, non-scaled polynomial bases are used. Theoretical and numerical results indicate that the stability of the original IMLS method decreases as the separation distance decreases. Then, using shifted and scaled polynomial bases, a stabilized algorithm of the IMLS method is proposed and analyzed. As an application, the stabilized IMLS method is finally introduced into the meshless Galerkin boundary node method (GBNM) to produce a stabilized GBNM for potential problems and Stokes problems. Numerical examples are given to demonstrate the stability and convergence of the presented stabilized algorithms.

      PubDate: 2016-11-06T23:18:28Z
       
  • A linear complementarity formulation of meshfree method for elastoplastic
           analysis of gradient-dependent plasticity
    • Abstract: Publication date: December 2016
      Source:Engineering Analysis with Boundary Elements, Volume 73
      Author(s): Guiyong Zhang, Yong Li, Haiying Wang, Zhi Zong
      This work presents a linear complementarity formulation for elastoplastic analysis of the gradient-dependent plasticity including large deformation problems. The formulation is based on the meshfree smoothed radial point interpolation method, where the parametric variational principle (PVP) is used in the form of linear complementarity and the gradient-dependent plasticity is represented by the linearization of yield criterion. The yield stress is linearly evolved through equivalent plastic strain as well as its Laplacian (namely second gradient). The global discretized system equations are transformed into a standard linear complementarity problem (LCP), which can be solved readily using the Lemke method. The proposed approach is capable of simulating material hardening/softening and strain localization. An extensive numerical study is performed to validate the proposed method and to investigate the effects of various parameters. The numerical results demonstrate that the proposed approach is accurate and stable for the elastoplastic analysis of 2D solids with gradient-dependent plasticity on strain localization.

      PubDate: 2016-11-06T23:18:28Z
       
  • Boundary element analysis of 3D cracks in anisotropic
           thermomagnetoelectroelastic solids
    • Abstract: Publication date: January 2017
      Source:Engineering Analysis with Boundary Elements, Volume 74
      Author(s): Iaroslav Pasternak, Roman Pasternak, Viktoriya Pasternak, Heorhiy Sulym
      The paper presents a general boundary element approach for analysis of 3D cracks in anisotropic thermomagnetoelectroelastic solids. Dual boundary integral equations are derived, which kernels are explicitly written. These equations do not contain volume integrals in the absence of distributed body heat and extended body forces, which is advantageous comparing to the existing approaches. The issues on the boundary element solution of these equations are discussed in details. The efficient numerical evaluation of kernels based on the trapezoid rule is proposed. Modified Kutt's quadrature with Chebyshev nodes is derived for integration of singular and hypersingular integrals. Nonlinear polynomial mappings are adopted for smoothing the integrand at the crack front, which is advantageous for accurate evaluation of field intensity factors. Special shape functions are introduced, which account for a square-root singularity of extended stress and heat flux at the crack front. The issues on numerical determination of field intensity factors are discussed. Several numerical examples are presented, which show the efficiency (low computational time and high precision) of the proposed boundary element formulation.

      PubDate: 2016-11-06T23:18:28Z
       
  • Boundary element analyses on the adhesive contact between an elastic
           sphere and a rigid half-space
    • Abstract: Publication date: January 2017
      Source:Engineering Analysis with Boundary Elements, Volume 74
      Author(s): Jiunn-Jong Wu, Yu Ju Lin
      Boundary element method is used to analyze the adhesive contact between an elastic sphere and a rigid half-space. Lennard-Jones potential is used for the surface traction. In the past, the simulation for the adhesive contact between spheres usually used paraboloid approximation for sphere surface. In this paper, the adhesive contact is investigated using exact sphere. A new algorithm for boundary element method is proposed. The S-shaped load-approach curve and the whole solution can be obtained. The result is compared with the adhesive contact between a rigid paraboloid and an elastic half-space, and that between an elastic paraboloid and a rigid half-space. It is found that the Tabor parameter and the radius of sphere affect the adhesive contact. As the Tabor parameter is larger, the effect of the radius is larger. As the radius is smaller, the pull-off force and the pull-off distance for fixed-grips device are smaller. The adhesive contact for rigid paraboloid/elastic half-space can approximate that for elastic paraboloid/rigid half-space and that for elastic sphere/rigid half-space with small Tabor parameter and large radius. Finally, an approximate equation for the pull-off force vs. Tabor parameter is proposed.

      PubDate: 2016-11-06T23:18:28Z
       
  • Quantification of cohesive fracture parameters based on the coupling of
           Bayesian updating and the boundary element method
    • Abstract: Publication date: January 2017
      Source:Engineering Analysis with Boundary Elements, Volume 74
      Author(s): Sergio Gustavo Ferreira Cordeiro, Edson Denner Leonel, Pierre Beaurepaire
      The fracture process in concrete involves nonlinear mechanical phenomena, which are accurately represented via the cohesive crack model. Due to the inherent randomness of this process, large scatter is observed in the experimental results. Therefore, significant uncertainties control the parameters that govern the theoretical approaches for concrete fracture modelling. In this study, a stochastic procedure for the parameter quantification of concrete nonlinear fracture models is presented. The Boundary Element Method is coupled to the cohesive model to model the nonlinear fracture phenomena. The Bayesian updating approach is subsequently applied to quantify the parameters that govern the cohesive laws based on the results of experimental analyses. The stochastic procedure enables the use of different cohesive laws to identify the law that provides the best agreement between numerical responses and experimental responses. A three-point bending notched test regarding different concrete mixtures is used to demonstrate the relevance of the proposed scheme.

      PubDate: 2016-11-06T23:18:28Z
       
  • GPU acceleration of the boundary element method for shear-deformable
           bending of plates
    • Abstract: Publication date: January 2017
      Source:Engineering Analysis with Boundary Elements, Volume 74
      Author(s): Ahmed A. Torky, Youssef F. Rashed
      This paper presents a novel implementation of GPU computing for boundary element method (BEM) formulation of plates. The new GPU code written in CUDA Fortran alters three kernels: the calculation of influence matrices, the solution of equations, and the computation of internal values. Comparisons for computation time and different GPU architecture are presented. The formulation is implemented for both constant and quadratic elements. The efficiency of the parallel quadratic code is demonstrated via analysis of practical building slabs. The benefits of parallel computing of the solution of the system of equations and of points inside the domain are discussed.

      PubDate: 2016-11-06T23:18:28Z
       
  • BEM numerical simulation of coupled heat, air and moisture flow through a
           multilayered porous solid
    • Abstract: Publication date: January 2017
      Source:Engineering Analysis with Boundary Elements, Volume 74
      Author(s): L. Škerget, A. Tadeu, J. Ravnik
      The problem of unsteady coupled moisture, air and heat energy transport through a porous solid is studied numerically using singular boundary integral representation of the governing equations. The governing transport equations are written and solved for the continuous driving potentials, i.e. relative humidity, temperature and air pressure. The boundary and interface conditions are discussed. The integral equations are discretized using mixed-boundary elements and a multidomain method also known as the macro-elements technique. The numerical model uses quadratic approximation over space and linear approximation over time for all field functions, which provides highly accurate numerical results. Three test benchmark examples (moisture uptake in a semi-infinite region, air transfer through a lightweight wall, and moisture redistribution inside a multilayered wall with capillary-active interior insulation), were analyzed to show the applicability and accuracy of the simulation model developed.

      PubDate: 2016-11-06T23:18:28Z
       
  • The combination of the boundary element method and the numerical manifold
           method for potential problems
    • Abstract: Publication date: January 2017
      Source:Engineering Analysis with Boundary Elements, Volume 74
      Author(s): Fei Tan, Yu-Yong Jiao
      In this study, a boundary element method coupled with numerical manifold method is developed for solving potential problems in two dimension. This approach combines an equivalent variational form of a boundary integral equation with the finite cover approximations for generating the trial and test functions of the variational formulation. This method exploits the reduced dimensionality advantages of the BEM, and is especially suited for the problems with an unbounded domain. Since the local cover function can be chosen in the covers arbitrarily, the method provides flexibility to use different cover functions for different covers and increases the solution accuracy without any local mesh refinement, and the p-adaptive analysis can also be performed conveniently. The validity and efficiency of the present method are demonstrated by some numerical examples of potential problems.

      PubDate: 2016-11-06T23:18:28Z
       
  • A regularization scheme applied to the direct interpolation boundary
           element technique with radial basis functions for solving eigenvalue
           problem
    • Abstract: Publication date: January 2017
      Source:Engineering Analysis with Boundary Elements, Volume 74
      Author(s): Carlos Friedrich Loeffler, Webe João Mansur
      This paper shows a regularization scheme applied to the recently developed Direct Interpolation Technique with Radial Basis Functions (DIBEM) for elimination of the singularity that exists in the kernel of the domain integral. As a simple interpolation, the kernel is approximated directly in DIBEM; however, it is composed of the fundamental solution, distinct positions between the source points and the field points being thus required. Through the proposed regularization scheme, both sets of source points and field points, as well as base points used for interpolation with radial functions may have the same coordinates. This facilitates the data entry and also the implementation of several operational steps of the DIBEM formulation. Solution of eigenvalue problem, generated by the Helmholtz Equation, is here chosen to exemplify the efficacy of the regularization procedure, but many other problems can thus be addressed, particularly the diffusive-advective problem, that has higher level of singularity in the interpolated kernel.

      PubDate: 2016-11-06T23:18:28Z
       
 
 
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