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  Subjects -> ENGINEERING (Total: 2266 journals)
    - CHEMICAL ENGINEERING (190 journals)
    - CIVIL ENGINEERING (183 journals)
    - ELECTRICAL ENGINEERING (99 journals)
    - ENGINEERING (1195 journals)
    - ENGINEERING MECHANICS AND MATERIALS (391 journals)
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    - INDUSTRIAL ENGINEERING (64 journals)
    - MECHANICAL ENGINEERING (89 journals)

ENGINEERING (1195 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: 16)
IETE Journal of Research     Open Access   (Followers: 10)
IETE Technical Review     Open Access   (Followers: 11)
IIE Transactions     Hybrid Journal   (Followers: 2)
IIUM Engineering Journal     Open Access  
Implementation Science     Open Access   (Followers: 14)
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 Energética     Open Access  
Ingenieria Industrial. Actualidad y Nuevas Tendencias     Open Access  
Ingeniería Investigación y Desarrollo     Open Access  
Ingeniería solidaria     Open Access   (Followers: 1)
Ingenieria y Ciencia     Open Access  
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: 22)
International Archives of Science and Technology     Open Access  
International Communications in Heat and Mass Transfer     Hybrid Journal   (Followers: 19)
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: 3)
International Journal for the History of Engineering & Technology     Hybrid Journal   (Followers: 8)
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 Advanced Engineering Research and Science IJAERS     Open Access   (Followers: 6)
International Journal of Advanced engineering, Management and Science     Open Access   (Followers: 1)
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: 19)
International Journal of Air-Conditioning and Refrigeration     Hybrid Journal   (Followers: 8)
International Journal of Antennas and Propagation     Open Access   (Followers: 9)
International Journal of Applied Ceramic Technology     Hybrid Journal   (Followers: 8)
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: 4)
International Journal of Automotive Technology and Management     Hybrid Journal   (Followers: 6)
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 Complexity in Applied Science and Technology     Hybrid Journal  
International Journal of Computer Aided Engineering and Technology     Hybrid Journal   (Followers: 2)
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: 9)
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 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: 6)
International Journal of Engineering and Manufacturing     Open Access   (Followers: 1)
International Journal of Engineering and Technologies     Open Access   (Followers: 1)
International Journal of Engineering Business Management     Open Access   (Followers: 1)
International Journal of Engineering Education     Full-text available via subscription   (Followers: 6)
International Journal of Engineering Management and Economics     Hybrid Journal   (Followers: 4)
International Journal of Engineering Mathematics     Open Access   (Followers: 3)
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: 3)
International Journal of Engineering Science     Hybrid Journal   (Followers: 6)
International Journal of Engineering Systems Modelling and Simulation     Hybrid Journal   (Followers: 9)
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 Foresight and Innovation Policy     Hybrid Journal   (Followers: 7)
International Journal of Fracture     Hybrid Journal   (Followers: 11)
International Journal of Geo-Engineering     Open Access   (Followers: 1)
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: 32)
International Journal of Heat and Mass Transfer     Hybrid Journal   (Followers: 168)
International Journal of Heavy Vehicle Systems     Hybrid Journal   (Followers: 6)
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     Hybrid Journal   (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: 3)
International Journal of Lifecycle Performance Engineering     Hybrid Journal   (Followers: 1)
International Journal of Machine Tools and Manufacture     Hybrid Journal   (Followers: 7)
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: 5)
International Journal of Mathematical Education in Science and Technology     Hybrid Journal   (Followers: 9)
International Journal of Mathematics in Operational Research     Hybrid Journal  
International Journal of Medical Engineering and Informatics     Hybrid Journal   (Followers: 4)
International Journal of Micro Air Vehicles     Full-text available via subscription   (Followers: 8)
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: 5)
International Journal of Nanomanufacturing     Hybrid Journal  
International Journal of Nanoscience     Hybrid Journal   (Followers: 1)
International Journal of Nanotechnology     Hybrid Journal   (Followers: 6)
International Journal of Nanotechnology and Molecular Computation     Full-text available via subscription   (Followers: 3)
International Journal of Navigation and Observation     Open Access   (Followers: 19)
International Journal of Network Management     Hybrid Journal   (Followers: 1)
International Journal of Nonlinear Dynamics and Control     Hybrid Journal  
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: 7)
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: 7)
International Journal of Plastics Technology     Hybrid Journal   (Followers: 1)
International Journal of Polymer Analysis and Characterization     Hybrid Journal   (Followers: 7)
International Journal of Polymer Science     Open Access   (Followers: 23)
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: 3)
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: 13)
International Journal of Renewable Energy Technology     Hybrid Journal   (Followers: 10)
International Journal of Robust and Nonlinear Control     Hybrid Journal   (Followers: 4)
International Journal of Science Engineering and Advance Technology     Open Access   (Followers: 1)
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: 3)
International Journal of Software Engineering and Knowledge Engineering     Hybrid Journal   (Followers: 5)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 6)
International Journal of Speech Technology     Hybrid Journal   (Followers: 8)
International Journal of Spray and Combustion Dynamics     Hybrid Journal   (Followers: 13)
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: 15)
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)

  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  [3030 journals]
  • Analysis of EM scattering from composite conducting-dielectric objects by
           time domain non-conformal VSIE
    • Abstract: Publication date: June 2017
      Source:Engineering Analysis with Boundary Elements, Volume 79
      Author(s): G.S. Cheng, Y.L. Hu, D.Z. Ding, R.S. Chen
      To analyze the transient electromagnetic (EM) scattering from the composite structure containing inhomogeneous dielectric volumes and perfect electrically conducting (PEC) bodies efficiently and flexibly, a marching-on-in-time (MOT) based time domain non-conformal volume surface integral equations (TD-VSIE) method is proposed. The non-conformal volume integral equation scheme and surface integral equation discontinuous Galerkin (IEDG) method are combined to realize the non-conformal meshes discretization for composite objects. For some composite objects containing fine structure or inhomogeneous dielectric materials, notable reduction in the number of the unknowns can be obtained without sacrificing accuracy. Moreover, a hybrid mesh scheme is introduced to further improve the efficiency. Several numerical results are proposed to demonstrate the validity and flexibility of the proposed scheme.

      PubDate: 2017-04-23T02:56:31Z
       
  • A meshless approach to non-local damage modelling of concrete
    • Abstract: Publication date: June 2017
      Source:Engineering Analysis with Boundary Elements, Volume 79
      Author(s): Behzad V. Farahani, J. Belinha, F.M. Andrade Pires, António J.M. Ferreira, P.M.G.P. Moreira
      A non-linear continuum damage mechanics model for concrete constructions is analysed using a radial point interpolation meshless method (RPIM). The fundamental mathematical relations and the material model are fully characterized. The 2D plane stress RPIM formulation is extended to a rate-independent standard (local) damage model considering both tension and compression static states. Additionally, in this work, the local damage formulation is modified considering a non-local constitutive damage criterion with regard to a Helmholtz free energy potential. Here, the internal variational fields, such as local and non-local damage variables, are determined by a return-mapping damage algorithm. Due to the non-linear nature of the phenomenon, a displacement controlled Newton-Raphson iterative approach is adopted to attain the non-linear damage solution. In the end, the performance of the proposed non-local damage model is evaluated using an experimental test of a notched-three-point bending beam available in the literature. The obtained solution shows that the meshless methods are capable to effectively analyse concrete structures assuming a non-linear non-local continuum damage model.

      PubDate: 2017-04-23T02:56:31Z
       
  • Comparison between the formulation of the boundary element method that
           uses fundamental solution dependent of frequency and the direct radial
           basis boundary element formulation for solution of Helmholtz problems
    • Abstract: Publication date: June 2017
      Source:Engineering Analysis with Boundary Elements, Volume 79
      Author(s): C.F. Loeffler, P.V.M. Pereira, L.O.C. Lara, W.J. Mansur
      Seeking to validate a solution technique for Helmholtz problems, the Boundary Element Method with Direct Integration, which applies radial basis functions to approach the inertia term, is used to solve numerically problems governed by Helmholtz Equation. The standard Boundary Element formulation that employs the fundamental solution correlated to the Helmholtz Equation and has the frequency of excitation as argument is used for comparison. Thus, examples comprising the direct solution of Helmholtz problems are solved with both Boundary Element formulations and then their results are compared with available analytical solutions.

      PubDate: 2017-04-23T02:56:31Z
       
  • An interaction integral and a modified crack closure integral for
           evaluating piezoelectric crack-tip fracture parameters in BEM
    • Abstract: Publication date: June 2017
      Source:Engineering Analysis with Boundary Elements, Volume 79
      Author(s): Jun Lei, Lili Yun, Chuanzeng Zhang
      To evaluate the crack-tip field intensity factors of a piezoelectric crack with any inclined angle, the current widely-used interaction integral method (I-integral) is here extended to the boundary element applications under some coordinate transformations. As well, a new modified crack closure integral method (MCCI) is proposed by considering the discontinuous quarter-point singular elements for the crack-face discretization arising from the dual boundary element method (BEM). This dual BEM involves the strongly singular displacement boundary integral equations (BIEs) for the external boundary and the hypersingular traction BIEs for the crack faces. The crack-tip fracture parameters evaluated by the I-integral and MCCI are verified by the existing analytical solutions and meanwhile, compared with those results achieved by the classical displacement extrapolation method and the J-integral. Three examples are presented to show the high accuracy of the interaction integral method and the improvement of MCCI for the piezoelectric crack problems.

      PubDate: 2017-04-23T02:56:31Z
       
  • The time-dependent boundary element method formulation applied to dynamic
           analysis of Euler-Bernoulli beams: the linear θ method
    • Abstract: Publication date: June 2017
      Source:Engineering Analysis with Boundary Elements, Volume 79
      Author(s): R.F. Scuciato, J.A.M. Carrer, W.J. Mansur
      In this paper, the dynamic analysis of Euler-Bernoulli beams is performed with the time-dependent Boundary Element Method formulation (TD-BEM). In the standard formulation, the variables related to the essential boundary conditions (displacement and rotation) are assumed to vary linearly in time, i.e., within each time interval, whereas the variables related to the natural boundary conditions (shear force and bending moment) are assumed to have a constant time variation. Different hypothesis concerning the time behavior of these quantities lead to unstable and inaccurate results. In the linear θ method, on the other hand, all the variables are assumed to have a linear time variation and reliable results are achieved. These results can be seen in the examples presented in this article, which contain the four usual types of beams under continuously distributed and concentrated loadings.

      PubDate: 2017-04-23T02:56:31Z
       
  • Using radial basis function-generated finite differences (RBF-FD) to solve
           heat transfer equilibrium problems in domains with interfaces
    • Abstract: Publication date: June 2017
      Source:Engineering Analysis with Boundary Elements, Volume 79
      Author(s): Bradley Martin, Bengt Fornberg
      When thermal diffusivity does not vary smoothly within a computational domain, standard numerical methods for solving heat equilibrium problems often converge to an inaccurate solution. In the present paper, we discuss a mesh-free, radial basis function-generated finite difference (RBF-FD)-based method for designing stencil weights that can be applied directly to data that crosses an interface. The approach produces a very accurate solution when thermal diffusivity varies smoothly on either side of an interface. It continues to produce high-quality results when a region between two interfaces is much smaller that the distance between adjacent discrete data nodes in the domain (as becomes the case for thin, nearly insulating layers). We give several test cases that demonstrate the method solving heat equilibrium problems to 4th-order accuracy in the presence of smoothly-curved interfaces.

      PubDate: 2017-04-09T01:24:40Z
       
  • Using radial basis function-generated finite differences (RBF-FD) to solve
           heat transfer equilibrium problems in domains with interfaces
    • Abstract: Publication date: June 2017
      Source:Engineering Analysis with Boundary Elements, Volume 79
      Author(s): Bradley Martin, Bengt Fornberg
      When thermal diffusivity does not vary smoothly within a computational domain, standard numerical methods for solving heat equilibrium problems often converge to an inaccurate solution. In the present paper, we discuss a mesh-free, radial basis function-generated finite difference (RBF-FD)-based method for designing stencil weights that can be applied directly to data that crosses an interface. The approach produces a very accurate solution when thermal diffusivity varies smoothly on either side of an interface. It continues to produce high-quality results when a region between two interfaces is much smaller that the distance between adjacent discrete data nodes in the domain (as becomes the case for thin, nearly insulating layers). We give several test cases that demonstrate the method solving heat equilibrium problems to 4th-order accuracy in the presence of smoothly-curved interfaces.

      PubDate: 2017-04-09T01:24:40Z
       
  • A meshless radial basis function method for steady-state
           advection-diffusion-reaction equation in arbitrary 2D domains
    • Abstract: Publication date: June 2017
      Source:Engineering Analysis with Boundary Elements, Volume 79
      Author(s): S.Y. Reutskiy, Ji Lin
      In this paper, we present a new meshless method for the simulation of 2D linear and non-linear steady-state advection-diffusion-reaction equations (ADRE). The proposed method is simple and straight forward. The solution to the problem is separated into the approximation of the boundary conditions and the approximation of the ADRE inside the solution domain. The approximation of the boundary conditions is approximated by the chosen basis functions, and the approximation of the ADRE inside the solution domain is approximated by the basis functions which satisfy the homogeneous boundary conditions of the problem. Each basis function used in the algorithm is a sum of a radial basis function (RBF) and a special correcting function which is chosen to satisfy the corresponding homogeneous boundary conditions of the problem. The final approximated solution is given in the form which satisfies the boundary conditions of the initial problem with any choice of free parameters. Then these free parameters are obtained using the collocation techniques. The numerical examples demonstrate the high accuracy and efficiency of the proposed method in solving 2D ADRE in arbitrary domains.

      PubDate: 2017-04-09T01:24:40Z
       
  • A meshless radial basis function method for steady-state
           advection-diffusion-reaction equation in arbitrary 2D domains
    • Abstract: Publication date: June 2017
      Source:Engineering Analysis with Boundary Elements, Volume 79
      Author(s): S.Y. Reutskiy, Ji Lin
      In this paper, we present a new meshless method for the simulation of 2D linear and non-linear steady-state advection-diffusion-reaction equations (ADRE). The proposed method is simple and straight forward. The solution to the problem is separated into the approximation of the boundary conditions and the approximation of the ADRE inside the solution domain. The approximation of the boundary conditions is approximated by the chosen basis functions, and the approximation of the ADRE inside the solution domain is approximated by the basis functions which satisfy the homogeneous boundary conditions of the problem. Each basis function used in the algorithm is a sum of a radial basis function (RBF) and a special correcting function which is chosen to satisfy the corresponding homogeneous boundary conditions of the problem. The final approximated solution is given in the form which satisfies the boundary conditions of the initial problem with any choice of free parameters. Then these free parameters are obtained using the collocation techniques. The numerical examples demonstrate the high accuracy and efficiency of the proposed method in solving 2D ADRE in arbitrary domains.

      PubDate: 2017-04-09T01:24:40Z
       
  • Numerical simulation of 3D nonlinear Schrödinger equations by using the
           localized method of approximate particular solutions
    • Abstract: Publication date: May 2017
      Source:Engineering Analysis with Boundary Elements, Volume 78
      Author(s): Ji Lin, Yongxing Hong, Lei-Hsin Kuo, Chein-Shan Liu
      In this paper, we describe a novel sparse meshless approach to the simulations of three-dimensional time-dependent nonlinear Schrödinger equations. Our procedure is implemented in two successive steps. In the first step, the implicit-Euler scheme is applied for approximating the functional dependence of the solution on the temporal variables. Then, in the second step, the novel localized method of approximate particular solutions (LMAPS) is utilized for highly accurate and efficient numerical approximations of spatial systems. In the implementation of the LMAPS, the closed form particular solutions for the Laplace operator using the Gaussian radial basis function are used. Numerical experiments are provided to verify the stability and efficiency of this method. In summary, the proposed algorithm is efficient and stable, and the magnitude of the error is at about 10−3 for 3D nonlinear Schrödinger problems.

      PubDate: 2017-04-09T01:24:40Z
       
  • Numerical simulation of 3D nonlinear Schrödinger equations by using the
           localized method of approximate particular solutions
    • Abstract: Publication date: May 2017
      Source:Engineering Analysis with Boundary Elements, Volume 78
      Author(s): Ji Lin, Yongxing Hong, Lei-Hsin Kuo, Chein-Shan Liu
      In this paper, we describe a novel sparse meshless approach to the simulations of three-dimensional time-dependent nonlinear Schrödinger equations. Our procedure is implemented in two successive steps. In the first step, the implicit-Euler scheme is applied for approximating the functional dependence of the solution on the temporal variables. Then, in the second step, the novel localized method of approximate particular solutions (LMAPS) is utilized for highly accurate and efficient numerical approximations of spatial systems. In the implementation of the LMAPS, the closed form particular solutions for the Laplace operator using the Gaussian radial basis function are used. Numerical experiments are provided to verify the stability and efficiency of this method. In summary, the proposed algorithm is efficient and stable, and the magnitude of the error is at about 10−3 for 3D nonlinear Schrödinger problems.

      PubDate: 2017-04-09T01:24:40Z
       
  • A simple FSDT-based meshfree method for analysis of functionally graded
           plates
    • Abstract: Publication date: June 2017
      Source:Engineering Analysis with Boundary Elements, Volume 79
      Author(s): Tan-Van Vu, Ngoc-Hung Nguyen, Amir Khosravifard, M.R. Hematiyan, Satoyuki Tanaka, Tinh Quoc Bui
      Modeling of mechanical behavior of plates has been accomplished in the past decades, with different numerical strategies including the finite element and meshfree methods, and with a range of plate theories including the first-order shear deformation theory (FSDT). In this paper, we propose an efficient numerical meshfree approach to analyze static bending and free vibration of functionally graded (FG) plates. The kinematics of plates is based on a novel simple FSDT, termed as S-FSDT, which is an effective four-variable refined plate theory. The S-FSDT requires C1-continuity that is satisfied with the basis functions based on moving Kriging interpolation. Some major features of the approach can be summarized: (a) it is less computationally expensive due to having fewer unknowns; (b) it is naturally free from shear-locking; (c) it captures the physics of shear-deformation effect present in the conventional FSDT; (d) the essential boundary conditions can straightforwardly be treated, the same as the FEM; and (e) it can deal with both thin and thick plates. All these features will be demonstrated through numerical examples, which are to confirm the accuracy and effectiveness of the proposed method. Additionally, a discussion on other possible choices of correlation functions used in the model is given.

      PubDate: 2017-04-02T00:41:19Z
       
  • Boundary-based finite element method for two-dimensional anisotropic
           elastic solids with multiple holes and cracks
    • Abstract: Publication date: June 2017
      Source:Engineering Analysis with Boundary Elements, Volume 79
      Author(s): Chyanbin Hwu, Shao-Tzu Huang, Chung-Chaio Li
      A special boundary element for the two-dimensional anisotropic elastic solids containing a single elliptical hole or crack is applied. The main feature of this special boundary element is that no meshes are needed along the hole or crack boundary. Take this special boundary element as a base, in this paper a new method called boundary-based finite element method is developed to deal with the problems of two-dimensional anisotropic elastic solids containing multiple holes and cracks. This method is established by using the relation between nodal force of finite element and surface traction of boundary element. With the aid of this relation, a combination of boundary elements can be transformed into a single finite element. By purposely arranging each subregion with a single hole or crack and assembling the entire region according to the rule of finite element method, the problems with multiple holes and cracks can be solved. Furthermore, simple formulae to evaluate the stress concentration factor of hole and the stress intensity factors of crack are derived, by which these factors can be evaluated by using only the remote boundary displacements and tractions. Accuracy and efficiency are illustrated by comparison with analytical solutions, conventional boundary element, and finite element method.

      PubDate: 2017-04-02T00:41:19Z
       
  • Stochastic analysis of moderately thick plates using the generalized
           polynomial chaos and element free Galerkin method
    • Abstract: Publication date: June 2017
      Source:Engineering Analysis with Boundary Elements, Volume 79
      Author(s): Ehsan Bahmyari, Mohammad Reza Khedmati, C. Guedes Soares
      In this paper, the element free Galerkin method is combined with the generalized polynomial chaos to quantify the uncertainties in the bending analysis of shear deformable plates with elastically restrained edges resting on a Pasternak elastic foundation with random system properties. The plate modules of elasticity, stiffnesses of the elastically restrained edges and the foundation stiffnesses are considered as random processes and are represented by using the Karhunen–Loève expansion. It is shown that the results obtained by the presented method are in a very good agreement with the results of Monte Carlo simulations in spite of using low order polynomials in the generalized polynomial chaos expansion. Also the applicability and versatility of the presented method are demonstrated by solving numerical examples for various values of coefficient of variations, aspect ratio, thickness and several combinations of boundary conditions, different types of lateral loading and various values of stiffnesses of restrained edges and elastic foundation.

      PubDate: 2017-04-02T00:41:19Z
       
  • The meshless local collocation method for solving multi-dimensional
           Cahn-Hilliard, Swift-Hohenberg and phase field crystal equations
    • Abstract: Publication date: May 2017
      Source:Engineering Analysis with Boundary Elements, Volume 78
      Author(s): Mehdi Dehghan, Mostafa Abbaszadeh
      The collocation technique based on the radial basis functions (RBFs) method is simple and efficient for solving a wide area of problems. But the mentioned technique is poor for solving problems that have shock (advection problems) or the discontinuous initial condition. The local RBFs collocation technique is a meshless method based on the strong form. The use of local collocation RBFs method overcomes the mentioned important issue. In the current paper, based on the proposed idea in Wang (2015) [54], we consider a linear combination of shape functions of local radial basis functions collocation method and moving Kriging interpolation technique. For showing the efficiency of new technique, some multi-dimensional problems such as Cahn-Hilliard, Swift-Hohenberg and phase field crystal equations have been chosen. Moreover, several test problems are given that show the acceptable accuracy and efficiency of the proposed scheme.

      PubDate: 2017-03-25T00:06:00Z
       
  • Application of the ‘FE-Meshfree’ QUAD4 with continuous nodal stress
           using radial-polynomial basis functions for vibration and geometric
           nonlinear analyses
    • Abstract: Publication date: May 2017
      Source:Engineering Analysis with Boundary Elements, Volume 78
      Author(s): Yongtao Yang, Guanhua Sun, Hong Zheng
      A hybrid ‘FE-Meshfree’ four-node quadrilateral element with continuous nodal stress using radial-polynomial basis functions (Quad4-RPIMcns), was recently proposed for static analysis. The Quad4-RPIMcns element can be considered as a development of the previous partition-of-unity (PU) based ‘FE-Meshfree’ QUAD4 element (Quad4-RPIM) which uses FE shape functions to construct the PU and radial-polynomial basis functions to construct the local approximation (LA), so as to synergize the individual strengths of finite element and meshfree methods. As a result, high order global approximations in Quad4-RPIMcns element could be easily constructed without adding extra nodes and DOFs, thereby achieving high accuracy and convergence rate. In this paper, the element is further applied to conduct free vibration, forced vibration and geometric nonlinear analyses of two-dimensional solids. Several numerical test problems are solved and the performance of the element is compared with that of the three-node triangular element (Trig3) and four-node isoparametric quadrilateral element (Quad4). Numerical results show that Quad4-RPIMcns element has higher tolerance to mesh distortion and gives more accurate solution as compared to Trig3 and Quad4 elements.

      PubDate: 2017-03-10T02:34:12Z
       
  • On the ill-conditioned nature of C∞ RBF strong collocation
    • Abstract: Publication date: May 2017
      Source:Engineering Analysis with Boundary Elements, Volume 78
      Author(s): E.J. Kansa, P. Holoborodko
      Continuously differentiable radial basis functions ( C ∞ -RBFs) are the best method to solve numerically higher dimensional partial differential equations (PDEs). Among the reasons are: 1. An n-dimensional problem becomes a one-dimensional radial distance problem, 2. The convergence rate increases with the dimensionality, 3. Such RBFs possess spectral convergence.Finitely supported polynomial methods only converge at polynomial rates. C ∞ -RBFs have global support; the systems of equations may become computationally singular if the condition number exceeds the inverse machine epsilon, ε M . The solution to computational singularity is to decrease the effective ε M by either hardware or software methods. Computer scientists developed rapidly executable multi-precision packages.

      PubDate: 2017-03-05T14:12:36Z
       
  • A new implementation of BEM by an expanding element interpolation method
    • Abstract: Publication date: May 2017
      Source:Engineering Analysis with Boundary Elements, Volume 78
      Author(s): Jianming Zhang, Lei Han, Weicheng Lin, Yunqiao Dong, Chuanming Ju
      A new implementation of boundary element method (BEM) by an expanding element interpolation method is presented in this paper. The expanding element is achieved by collocating virtual nodes along the perimeter of the traditional discontinuous element. With the virtual nodes, both continuous and discontinuous fields on the domain boundary can be accurately approximated, and the interpolation accuracy increases by two orders compared with the original discontinuous element. The boundary integral equations are built up for the inner nodes of the traditional discontinuous elements, only (taking these nodes as source points), while the virtual nodes are used for connecting the shape functions at the source points, thus the size of the final system of linear equations will not increase. The expanding element inherits the advantages of both the continuous and discontinuous elements while overcomes their disadvantages. Successful numerical examples with different boundary conditions have demonstrated that our new implementation is very encouraging and promising.

      PubDate: 2017-02-19T16:30:58Z
       
  • A moving least squares based meshless local petrov-galerkin method for the
           simulation of contaminant transport in porous media
    • Abstract: Publication date: May 2017
      Source:Engineering Analysis with Boundary Elements, Volume 78
      Author(s): Swathi Boddula, T.I. Eldho
      Contamination of soil, surface and subsurface water resources through direct or indirect sources is a major problem in many parts of the world. To understand the contamination process in the porous media, we have to simulate the contaminant transport mechanism and predict its behaviour with respect to space and time. The contaminant transport process can be simulated by solving the well posed advection-dispersion partial differential equation by using numerical techniques with appropriate initial and boundary conditions. The transport equation is generally solved using grid based techniques like Finite Difference Method (FDM) and Finite Element Method (FEM). The Meshless methods are alternatively developed numerical methods to overcome the limitations of aforementioned grid based techniques. This paper presents a newly developed Meshless Local Petrov-Galerkin (MLPG) model based on the moving least squares (MLS) method for numerical simulation of contaminant transport equation in porous media. The Meshless MLPG-MLS model has been developed for one- and two- dimensional problems in MATLAB. These models are investigated and verified with available analytical and numerical solutions for its accuracy and efficiency. The models gave quiet promising results showing the efficacy and applicability of the method for the simulation of contaminant transport in porous media.

      PubDate: 2017-02-19T16:30:58Z
       
  • Dynamic 2.5-D Green's function for a point load or a point fluid source in
           a layered poroelastic half-space
    • Abstract: Publication date: April 2017
      Source:Engineering Analysis with Boundary Elements, Volume 77
      Author(s): Chao He, Shunhua Zhou, Peijun Guo, Honggui Di, Junhua Xiao
      The complete dynamic two-and-a-half-dimensional (2.5-D) Green's function for an internal point load or fluid source buried in a layered poroelastic half-space is derived and applied to the 2.5-D boundary element method (BEM) in this paper. Based on Biot's theory, the general solutions are derived using the potential decomposition method and the Fourier transform. Utilizing the boundary conditions of the free surface, interfaces and bottom half-space, as well as the general solutions, the complete 2.5-D Green's function for a layered poroelastic half-space is obtained using the transmission and reflection matrix (TRM) method. The solutions presented in this paper are free of numerical instability for the high frequency and large layer thickness. The proposed 2.5-D Green's function is verified by comparison with the existing solutions. A case study of calculating vibrations from a semi-circular tunnel embedded in a layered poroelastic half-space is presented using the 2.5-D BEM along with the proposed 2.5-D Green's function. The layer interfaces and the surface of the poroelastic half-space no longer have to be meshed, avoiding spurious reflections at mesh truncations. The boundary element mesh can be limited to the surface of the tunnel, significantly reducing the size of the boundary element mesh.

      PubDate: 2017-02-12T15:25:59Z
       
  • Single layer regularized meshless method for three dimensional exterior
           acoustic problem
    • Abstract: Publication date: April 2017
      Source:Engineering Analysis with Boundary Elements, Volume 77
      Author(s): Lin Liu
      The Regularized Meshless Method (RMM) is a meshless boundary method. Its source points and physical points are overlapped. The substraction and adding-back technique is utilized to avoid the singularity of the fundamental solution. It is simple and easy to be programmed. But the double layer potential should be adopted in the desingularity technique. Here the single layer potential is employed to circumvent the singularity. The substraction and adding-back technique is succeeded, but the careful selection of particular solution for the null-fields boundary integral equation is chosen to derive the diagonal elements for the Laplace Dirichlet problem. By this particular solution, the diagonal elements can be represented by the single layer potential. Here it is extended to the exterior Helmholtz problem by relationships between Laplace and Helmholtz singularities. The fictitious frequencies are avoided by the Burton-Miller type formula and Dual Surface technique. The accuracy of these methods are shown by three typical examples.

      PubDate: 2017-02-12T15:25:59Z
       
  • Freeze-drying modeling of vial using BEM
    • Abstract: Publication date: April 2017
      Source:Engineering Analysis with Boundary Elements, Volume 77
      Author(s): M. Ramšak, J. Ravnik, M. Zadravec, M. Hriberšek, J. Iljaž
      The paper reports on development of Boundary Element Method (BEM) based numerical algorithm for the numerical simulation of the freeze drying process in a vial. In the paper the problems of freeze-drying modeling are covered in detail. The BEM based algorithm is developed for the axisymmetrical geometry case using the Subdomain BEM approach. A special feature of the algorithm is an implicit representation of the interface conditions at the sublimation front, which is a great advantage of the proposed numerical scheme. As a test case the freeze drying of skim milk in a vial is selected. The numerical results show a good agreement with reference data proving that the developed numerical model is appropriate, accurate and fast in simulating the primary and secondary drying stage. The numerical analysis also shows that the time step during the secondary drying stage can be increased by a factor 100, which reduces the computational time drastically.

      PubDate: 2017-02-12T15:25:59Z
       
  • Modeling of thermo-mechanical fracture behaviors based on cohesive
           segments formulation
    • Abstract: Publication date: April 2017
      Source:Engineering Analysis with Boundary Elements, Volume 77
      Author(s): Yuzhou Sun, K.M. Liew
      An element-free framework is developed to study the thermo-mechanical fracture behavior of materials based on the cohesive segments model, in which a crack is treated as a combination of a series of cohesive segments and a new cohesive segment is added whenever the cracking criterion is met at a node. Using the moving least-square shape functions as the partition of unity, the discontinuity field is approximated with extra degrees of freedom at the existing nodes. Cohesive constitutive laws are used to model force and heat transfer through cracks. Mechanical and temperature fields are incorporated into a coupled nonlinear system, and the crack problem is iteratively solved. The chosen numerical examples illustrate the efficiency and flexibility of the proposed method.

      PubDate: 2017-02-07T14:42:09Z
       
  • Numerical simulation of metal removal in laser drilling using radial point
           interpolation method
    • Abstract: Publication date: April 2017
      Source:Engineering Analysis with Boundary Elements, Volume 77
      Author(s): Diaa Abidou, Nukman Yusoff, Nik Nazri, M.A. Omar Awang, Mohsen A. Hassan, Ahmed A.D. Sarhan
      Prediction of penetration depth in metal laser drilling is done through a simple meshfree numerical model. 2D axisymmetric simplified model of transient metal laser drilling is proposed for continuous laser beam of Gaussian distribution with strong form of Radial Point Interpolation Method (RPIM) used for approximating the temperature field. The commonly used Multi-Quadrics (MQ) and Exponential (EXP) Radial Basis Functions (RBFs) are tested and compared with each other. The model logic is constructed in MATLAB code, while the results are compared with published numerical and experimental work. The simulation results give good agreement with the previous numerical and experimental work, showing the model reliability in predicting the penetration depth in such a physically complex process.

      PubDate: 2017-02-07T14:42:09Z
       
  • An implicit potential method along with a meshless technique for
           incompressible fluid flows for regular and irregular geometries in 2D and
           3D
    • Abstract: Publication date: April 2017
      Source:Engineering Analysis with Boundary Elements, Volume 77
      Author(s): G.C. Bourantas, V.C. Loukopoulos, H.A. Chowdhury, G.R. Joldes, K. Miller, S.P.A. Bordas
      We present the Implicit Potential (IPOT) numerical scheme developed in the framework of meshless point collocation. The proposed scheme is used for the numerical solution of the steady state, incompressible Navier-Stokes (N-S) equations in their primitive variable (u-v-w-p) formulation. The governing equations are solved in their strong form using either a collocated or a semi-staggered type meshless nodal configuration. The unknown field functions and derivatives are calculated using the Modified Moving Least Squares (MMLS) interpolation method. Both velocity-correction and pressure-correction methods applied ensure the incompressibility constraint and mass conservation. The proposed meshless point collocation (MPC) scheme has the following characteristics: (i) it can be applied, in a straightforward manner to: steady, unsteady, internal and external fluid flows in 2D and 3D, (ii) it equally applies to regular an irregular geometries, (iii) a distribution of points is sufficient, no numerical integration in space nor any mesh structure are required, (iv) there is no need for pressure boundary conditions since no pressure constitutive equation is solved, (v) it is quite simple and accurate, (vi) results can be obtained using collocated or semi-staggered nodal distributions, (vii) there is no need to compute the velocity potential nor the unit normal vectors and (viii) there is no need for a curvilinear system of coordinates. Simulations of fluid flow in 2D and 3D for regular and irregular geometries indicate the validity of the proposed methodology.

      PubDate: 2017-02-07T14:42:09Z
       
  • A coupled BEM/FEM formulation for drop interaction in Stokes flows with
           flexible and slip confining boundaries
    • Abstract: Publication date: April 2017
      Source:Engineering Analysis with Boundary Elements, Volume 77
      Author(s): Delfim Soares, Luiz C. Wrobel
      In this work, fluid-fluid-solid coupled models are analysed, considering the interaction of boundary and finite element techniques. In this context, the paper focuses on the study of deforming drops through bulk fluids bounded by flexible walls. Here, the fluid subdomains are assumed to be viscous and incompressible, and they are modelled by the BEM. The solid subdomains are assumed to be elastic, and they are modelled by the FEM. Both discontinuity of tractions on the fluid-fluid common boundaries and discontinuity of velocities on the fluid-solid interfaces are considered. For the discontinuity of velocities, a formulation based on nonlinear slip boundary conditions is adopted, which is treated employing a relaxed iterative approach. A Lagrangian representation is considered and remeshing is applied on the fluid-fluid interfaces, reducing the appearance of numerical problems. Numerical results are presented to illustrate the performance and potentialities of the proposed techniques.

      PubDate: 2017-02-07T14:42:09Z
       
  • Boundary-integral-based process for calculating stiffness matrices of
           space frame elements with axially varying cross section
    • Abstract: Publication date: April 2017
      Source:Engineering Analysis with Boundary Elements, Volume 77
      Author(s): F.C. de Araujo, R.A.T. Pereira
      This paper presents a strategy to directly compute the stiffness matrix of 3D (space) frame elements having arbitrary cross sections and generic rigidity variation along their axes. All the necessary section properties are determined by means of formulations based purely on boundary integrals. To determine the torsional constant and the torsion center, this strategy applies the Boundary Element Method (BEM). To model thin-walled cross-sections, the strategy calls for activating integration algorithms devised specifically to deal with the nearly singular integrals involved. To express all other section properties (i.e. area, first and second moments of area, and the shear form factors) in terms of boundary integrals, the strategy employs Green's theorem. The existing boundary-element meshes, used to determine the torsion constants, are employed to evaluate the corresponding boundary integrals. In applying the proposed strategy – the pure boundary-integral-based process (PBIP) – we consider space frame elements with geometrically complex cross-sections varying along their axes.

      PubDate: 2017-01-31T14:03:48Z
       
  • Iterative multi-domain BEM solution for water wave reflection by
           perforated caisson breakwaters
    • Abstract: Publication date: April 2017
      Source:Engineering Analysis with Boundary Elements, Volume 77
      Author(s): Yong Liu, Hua-Jun Li
      This study develops a full solution for water wave reflection by a partially perforated caisson breakwater with a rubble mound foundation using multi-domain BEM (boundary element method). Regular and irregular waves are both considered. A quadratic pressure drop condition on caisson perforated wall is adopted, and direct iterative calculations are performed. Due to the use of quadratic pressure drop condition, the effect of wave height on the energy dissipation by the perforated wall is well considered. This study also develops an iterative analytical solution for wave reflection by a partially perforated caisson breakwater on flat bottom using matched eigenfunction expansion method. The reflection coefficients calculated by the multi-domain BEM solution and the analytical solution are in excellent agreement. The present calculated results also agree reasonably well with experimental data from different literatures. Suitable values of discharge coefficient and blockage coefficient in the quadratic pressure drop condition are recommended for perforated caissons. The effects of the wave steepness, the blockage coefficient of perforated wall and the relative wave chamber width on the reflection coefficient are clarified. The present BEM solution is simple and reliable. It may be used for predicting the reflection coefficients of perforated caisson breakwaters in preliminary engineering design.

      PubDate: 2017-01-31T14:03:48Z
       
  • Optimizing the sacrificial anode cathodic protection of the rail canal
           structure in seawater using the boundary element method
    • Abstract: Publication date: April 2017
      Source:Engineering Analysis with Boundary Elements, Volume 77
      Author(s): Yong-Sang Kim, Jeongguk Kim, Dooho Choi, Jae-Yong Lim, Jung-Gu Kim
      This paper deals with the cathodic protection design for axle/wheel and rail of ‘rail-canal system’ in the ocean. The cathodic protection design was carried out using the boundary element method and was verified by the physical miniature tests. The optimum cathodic protection designs were determined based on the cathodic potential distribution and anode lifetime provided by the simulation. The unprotected physical miniature experienced widespread corrosion, whereas the protected miniature was covered with calcareous deposit, indicating that the surface was fully protected from corrosion. This study demonstrated that the boundary element can be applicable to the cathodic protection design of rail-canal structure.

      PubDate: 2017-01-24T13:13:15Z
       
  • Regularized boundary integral methods for three-dimensional potential
           flows
    • Abstract: Publication date: April 2017
      Source:Engineering Analysis with Boundary Elements, Volume 77
      Author(s): W.H. Tsao, W.S. Hwang
      The three-dimensional potential flow problems are solved by a boundary integral equation in this article. The boundary integral equation is regularized by a subtracting and adding-back technique in global elements. This technique utilizes several identities to eliminate the singularities or near singularities of surface integrals. In test cases, the convergence speed of this method for a smooth body is of the order N − 3 in one direction no matter how high-order quadrature is applied. For nearly singular integrals, several extremely oblate spheroids are tested to verify this method. These results illustrate that this method can effectively improve the nearly singular deficit when it exists. For the non-smooth bodies, the present method is applied to solve the mixed boundary value problems inside two kinds of vessels, which are sloshing motions. At last, some tests are compared between the boundary element methods (local elements) and the present method (global elements).

      PubDate: 2017-01-24T13:13:15Z
       
  • Numerical study of flow-excited noise of a submarine with full appendages
           
    • Abstract: Publication date: April 2017
      Source:Engineering Analysis with Boundary Elements, Volume 77
      Author(s): Huilan Yao, Huaixin Zhang, Hutao Liu, Wencheng Jiang
      Large eddy simulation (LES) is applied to simulate the flow field around a submarine with full appendages. The predicted ship resistance, velocity distributions and surface pressures are validated by experimental data. Dynamic velocity responses of the structure are obtained by solving the fluid-solid coupling equations. The flow noise and flow-excited noise of the submarine are predicted using the boundary element method (BEM). Flow noise predicted by the BEM and the Ffowcs Williams-Hawkings (FW-H) equations are compared and discussed. The spectra of flow-excited noise are different from those of flow noise, and the sound pressure level of flow-excited noise is larger than that of flow noise, especially when structural resonance occurs. Flow-excited noise rapidly decreases in the near-field and maintains a slow attenuation rate in the far-field. The influence of ship speed on flow-excited noise is investigated, and results show that the spectral characteristics of flow-excited noise of the submarine change greatly with different sailing speeds. To achieve noise reduction, different shell thicknesses and different numbers of longitudinal girders are investigated. It is found that increasing the shell thickness and the number of longitudinal girders can indeed reduce noise emission. It should be noted that the noise reduction effect might differ.

      PubDate: 2017-01-18T12:31:45Z
       
  • An element-free based IMLS-Ritz method for buckling analysis of
           nanocomposite plates of polygonal planform
    • Abstract: Publication date: April 2017
      Source:Engineering Analysis with Boundary Elements, Volume 77
      Author(s): L.W. Zhang
      The buckling behavior of nanocomposite plates of polygonal planform under in-plane loads is examined. The plate under consideration is reinforced by single-walled carbon nanotubes (CNTs). The governing eigenvalue equation to this problem is derived based on the first-order shear deformation plate theory (FSDT) with a set of element-free shape functions in approximating the two-dimensional displacement fields. To solve this eigenvalue equation, the element-free IMLS-Ritz method is employed to furnish the buckling solution. The convergence of the solution for the CNT-reinforced composite plates is examined. Comparison study is further carried out to validate the accuracy of the solution. A parametric study is performed by varying the CNT volume fraction, CNT distribution, plate thickness-to-apothem ratio and boundary conditions. This first known buckling solution may serve as benchmarks for future research.

      PubDate: 2017-01-18T12:31:45Z
       
  • Dynamic fracture analysis of the soil-structure interaction system using
           the scaled boundary finite element method
    • Abstract: Publication date: April 2017
      Source:Engineering Analysis with Boundary Elements, Volume 77
      Author(s): Denghong Chen, Shangqiu Dai
      Dynamic fracture analysis of the soil-structure interaction system by using the scaled boundary finite element method is presented in this paper. The polygon scaled boundary finite elements, which have some salient features to model any star convex polygons, are employed for modelling the near-field bounded domains. A procedure for coupling the bounded domains with an improved continued-fraction-based high-order transmitting boundary is established. The formulations of the soil-structure interaction system are coupled via the interaction force vector at the interface. The dynamic stress intensity factors and T-stress are extracted according to the definition of the generalized stress intensity factors. The dynamic stress intensity factors of the coupled system are evaluated accurately and efficiently. Two numerical examples are demonstrated to validate the developed method.

      PubDate: 2017-01-18T12:31:45Z
       
  • Three-dimensional dynamic ring load and point load Green's functions for
           
    • Abstract: Publication date: March 2017
      Source:Engineering Analysis with Boundary Elements, Volume 76
      Author(s): Saeed Cheshmehkani, Morteza Eskandari-Ghadi
      An analytical formulation is presented for three-dimensional Green's functions of continuously inhomogeneous linear viscoelastic transversely isotropic half-space subjected to either ring load or point load. It is assumed that the elastic moduli of the half-space vary in terms of depth as bounded exponentially functions, while the mass density is constant. The method of potential functions is used to partially decouple the governing equations, after which Fourier series expansion followed by Hankel integral transforms is applied to transform the partial differential equations to ordinary differential equations (ODEs) with variable coefficients. Then, Frobenius series method is employed to determine the potential functions and then the displacements and stresses in the transformed domain, which are used to evaluate these functions in physical domain. The validity of the formulations and numerical process is shown for several simplified cases comparing with the known solutions in the literature. Finally, the displacement and stress Green's functions are presented for several physical cases due to either unit ring load or unit point load. The results show that if the shear waves are produced in the interested direction, both inhomogeneity parameters and material damping may change the dynamic response of the half-space significantly, especially in high frequencies.

      PubDate: 2017-01-10T11:45:22Z
       
  • Modelling of acoustic and elastic wave propagation from underground
           structures using a 2.5D BEM-FEM approach
    • Abstract: Publication date: March 2017
      Source:Engineering Analysis with Boundary Elements, Volume 76
      Author(s): A. Romero, P. Galvín, J. António, J. Domínguez, A. Tadeu
      This paper presents a numerical method based on a two-and-a-half dimensional (2.5D) boundary element-finite element (BEM-FEM) coupled formulation to study noise and vibration from underground structures. The proposed model properly represents the soil-structure interaction problem and the radiated noise and vibration. The soil is modelled with the boundary element method, and the Green's function for a fluid-solid formation is taken as the fundamental solution to represent a solid half-space flattened by a fluid medium, which represents the soil and the air above the ground surface. The finite element method is used to represent structures and enclosed air volumes. The problem representation is limited to a soil-structure interface and the ground surface does not need to be discretised. Radiated noise and vibration are determined after the soil-structure interaction problem has been solved. We verify the proposed method by comparing the solution with an analytical solution for the wave propagation in a fluid-solid medium. Three examples are given to illustrate the noise and vibration radiated by tunnels. The results show that the soil-structure interaction influences the sound pressure field above the ground surface.

      PubDate: 2017-01-10T11:45:22Z
       
  • Fundamental solutions of a multi-layered transversely isotropic saturated
           half-space subjected to moving point forces and pore pressure
    • Abstract: Publication date: March 2017
      Source:Engineering Analysis with Boundary Elements, Volume 76
      Author(s): Zhenning Ba, Jianwen Liang
      The steady-state dynamic response of a multi-layered transversely isotropic (TI) saturated half-space due to point forces and pore pressure moving with a constant speed is investigated in this paper. To solve this problem, the dynamic stiffness method combined with the inverse Fourier transform is employed. First, the governing equations in terms of the displacement components and pore fluid pressure are solved in the transformed domain by employing the Fourier transform. Next, the exact three-dimensional (3D) dynamic stiffness matrices for the TI saturated layer, as well as the TI saturated half-space, are constructed, and the global dynamic matrix of the problem is formulated by assembling the dynamic matrices of the discrete layers and the underlying half-space. Finally, solutions in the frequency-wavenumber domain of the displacement, pore pressure and stress are obtained through the dynamic stiffness method. The result in the time-space domain is recovered by the Fourier synthesis of the frequency responses which, in turn, are obtained by numerical integration over on one horizontal wavenumber. The accuracy of the developed formulations is confirmed by comparison with existing solutions for an isotropic and saturated medium that is a special case of the more general problem addressed. Numerical results for both low and high source velocities are presented, and the effects of moving speed, material anisotropy, permeability, surface drainage condition and TI saturated layer on the dynamic response are analyzed. It is observed that the dynamic responses reach their peak values when the source velocity is equal to or approaches the phase velocities of SH-, qP1-, qP2- and qSV- in the horizontal direction and the phase velocity of qRayleigh waves. Material anisotropy is very important for the accurate assessment of the dynamic response due to the moving point forces and pore pressure in a TI saturated medium.

      PubDate: 2017-01-10T11:45:22Z
       
  • Why dual boundary element method is necessary?
    • Abstract: Publication date: March 2017
      Source:Engineering Analysis with Boundary Elements, Volume 76
      Author(s): Jeng-Tzong Chen, Ching-Yun Yueh, Yu-Lung Chang, Chun-Chiang Wen
      Dual boundary integral equation (BIE) was developed for problems containing degenerate boundaries in 1988 by Hong and Chen [Journal of Engineering Mechanics-ASCE, 114, 6, 1988] and was termed the dual boundary element method (BEM) in 1992 by Portela et al. [International Journal for Numerical Methods in Engineering, 33, 6, 1992]. After near 30 years, the dual BIE/BEM for the problem containing a zero-thickness barrier was revisited mathematically to study the rank deficiency from the viewpoint of the updating term and the updating document of singular value decomposition (SVD) [Journal of Mechanics, 31, 5, 2015]. In this paper, we revisit the dual BEM from the physical point of view. Although there is no zero-thickness barrier in the real world, it is always required to simulate a finite-thickness degenerate boundary to be zero-thickness in comparison with sea, air or earth scale. For example, a sheet pile, a screen, a crack problem, a thin airfoil and a breakwater were modeled by the geometry of zero-thickness. The role of the dual BEM is evident since Lafe et al. [Journal of the Hydraulics Division-ASCE, 106, 6, 1980] used the conventional BEM to model the finite-thickness pile wall to geometrically approximate zero-thickness barrier but numerically yielding divergent solution. On the contrary, we physically model the finite-thickness breakwater as a zero-thickness barrier. The breakwater is employed as an illustrative case to demonstrate that the dual BEM simulated by a zero-thickness barrier can yield more acceptable results to match the experiment data in comparison with those of the finite thickness using the conventional BEM. Finally, a single horizontal plate and two dual horizontal plates in vertical direction and in horizontal direction are three illustrative cases to tell you why the dual BEM is necessary not only in mathematics but also in physics.

      PubDate: 2017-01-10T11:45:22Z
       
  • Numerical simulation of three-dimensional double-diffusive natural
           convection in porous media by boundary element method
    • Abstract: Publication date: March 2017
      Source:Engineering Analysis with Boundary Elements, Volume 76
      Author(s): J. Kramer Stajnko, J. Ravnik, R. Jecl
      The paper presents numerical results for three-dimensional double-diffusive natural convection in a cubic enclosure fully filled with fluid saturated porous media. Two opposite vertical walls of the enclosure are subjected to different values of temperature and concentration, which causes buoyant and diffusive flow in the porous media domain. Mathematical model is based on the Brinkman-extended Darcy formulation as a governing momentum equation, which is coupled with the energy and species equations. The three-dimensional boundary element method based solver was used to solve the obtained set of partial differential equations. The existing numerical algorithm primarily derived for the pure fluid flow simulations was adopted to simulate transport phenomena in porous media. It is based on the combination of single and subdomain boundary element method, which solves the velocity-vorticity formulation of the governing equations. In the paper the influence of some governing parameters, specially the Rayleigh number, Darcy number and buoyancy coefficient are investigated in order to analyze the heat and mass transfer through porous enclosure. The numerical code is verified by comparison of the results with available previous numerical data found in the literature.

      PubDate: 2017-01-10T11:45:22Z
       
  • Elastodynamic analysis of regular polygonal CNT-reinforced composite
           plates via FSDT element-free method
    • Abstract: Publication date: March 2017
      Source:Engineering Analysis with Boundary Elements, Volume 76
      Author(s): L.W. Zhang, W.H. Liu, L.N. Xiao
      A comprehensive study on elastodynamic behavior of regular polygonal carbon nanotube (CNT) reinforced functionally graded composite plates subjected to a sudden transverse dynamic load is presented in this paper. This analysis uses as its base the first-order shear deformation theory (FSDT) and the element-free IMLS-Ritz method, to conduct a numerical simulation. A numerical time integration for the dynamic problems is performed using the Newmark-β method. Convergence studies are carried out for an isotropic square plate with different support sizes and different numbers of nodes. Parametric studies are further carried out to investigate the effect of four special regular polygons with different CNT volume fractions, CNT distribution types, plate apothem-to-thickness ratios and boundary conditions on the dynamic behaviors of regular polygonal CNT-reinforced composite plates.

      PubDate: 2017-01-10T11:45:22Z
       
  • A modification on strictly positive definite RBF-DQ method based on matrix
           decomposition
    • Abstract: Publication date: March 2017
      Source:Engineering Analysis with Boundary Elements, Volume 76
      Author(s): Saeed Kazem, Ali Hatam
      The infinitely smooth RBF methods are theoretically spectrally accurate for applying on scattered data interpolation, and also partial differential equations, but the interpolation matrices of them are extremely ill-conditioned especially for strictly positive definite ones. Therefore, an efficient technique to recover this problem is too important. In this article, a general matrix decomposition method for strictly positive definite RBFs interpolation matrix has been investigated. In the current decomposition the RBFs interpolation matrix is obtained as multiplication of some well-conditioned matrices. This decomposition has been applied to RBF-DQ method and its results more accurate weight coefficients when we involve solving PDEs.

      PubDate: 2017-01-10T11:45:22Z
       
  • Strategies using boundary integral equations for solving exterior
           anisotropic conduction problems outside long cylinders
    • Abstract: Publication date: March 2017
      Source:Engineering Analysis with Boundary Elements, Volume 76
      Author(s): A. Corfdir, G. Bonnet
      2D approximations can greatly alleviate the computing effort required to solve anisotropic conduction problems outside long 3D cylindrical domain using boundary integral methods. Two strategies can be used to this aim: either transform the anisotropic conduction problem into an isotropic one, or deal with the anisotropic 2D Green's function. In the first case, it is necessary to provide not only the new features of the transformed domain, but also the new expressions of the boundary conditions over the domain. Conversely, the anisotropic 2D Green's function is defined upto a constant which depends on the length of the cylindrical domain, as shown in the isotropic case. In addition, the use of anisotropic Green's function cannot avoid the occurrence in some cases of degenerate scales, which is well known in the isotropic case. The paper addresses these different points: construction of the anisotropic 2D Green's function and its relation with line sources, description of the transformation leading to an equivalent isotropic problem and finally study of the boundary integral solution of the equivalent 2D problem, including the occurence of degenerate scales.

      PubDate: 2016-12-30T11:03:48Z
       
  • The birth of the boundary element method from conception to application
    • Abstract: Publication date: Available online 27 December 2016
      Source:Engineering Analysis with Boundary Elements
      Author(s): Carlos A. Brebbia
      The Boundary Element Method (BEM) has now become a well established numerical technique with a number of computer programmes to its credit oriented towards industrial applications. They are reliable and robust tools which stress its unique features versus finite elements, ie reduced dimensionality which makes it easier to interface it to CAD codes; better accuracy, the elegant way in which moving boundaries are dealt with and the possibility of taking into consideration infinite domains without the need of introducing artificial boundaries. An excellent paper on the early work that led to the development of boundary elements has been given by A&D Cheng [1] and from which many of the illustrations depicting famous scientists were taken. The present contribution aims to explain further how the methodology developed and consolidated towards the end of the 1970s, beginning of the 1980s.

      PubDate: 2016-12-30T11:03:48Z
       
  • DRBEM formulation for transient Stokes flow with slip boundary condition
    • Abstract: Publication date: February 2017
      Source:Engineering Analysis with Boundary Elements, Volume 75
      Author(s): S. Gümgüm, Luiz C. Wrobel
      In this study, the effect of linear and nonlinear slip boundary conditions on the flow of a slow viscous fluid is investigated numerically. The boundary integral representation of the transient Stokes equations is given in primitive variables form. The fundamental solution to the steady Stokes equations is employed in the boundary element method (BEM) formulation. The time derivative is taken to the boundary with the dual reciprocity method and approximated by the finite difference method (FDM) until a steady-state is achieved. It is assumed that the fluid is capable of slip, with the slip velocity expressed as a function of shear rate at the wall. In the numerical tests, the fluid is initially assumed to be stationary; at each time step, the velocity boundary conditions along the walls are updated as the shear forces vary with time.

      PubDate: 2016-12-23T10:07:21Z
       
  • A note on the use of the Companion Solution (Dirichlet Green's function)
           on meshless boundary element methods
    • Abstract: Publication date: February 2017
      Source:Engineering Analysis with Boundary Elements, Volume 75
      Author(s): H. Power, N. Caruso, M. Portapila
      Most implementations of meshless BEMs use a circular integration contours (spherical in 3D) embedded into a local interpolation stencil with the so-called Companion Solution (CS) as a kernel, in order to eliminate the contribution of the single layer potential. However, the Dirichlet Green's Function (DGF) is the unique Fundamental Solution that is identically zero at any given close surface and therefore eliminates the single layer potential. One of the main objectives of this work is to show that the CS is nothing else than the DGF for a circle collocated at its origin. The use of the DGF allows the collocation at more than one point, permitting the implementation of a P-adaptive scheme in order to improve the accuracy of the solution without increasing the number of subregions. In our numerical simulations, the boundary conditions are imposed at the interpolation stencils in contact with the problem boundary instead of at the corresponding integration surfaces, permitting always the use of circular integration contours, even in regions near or in contact with the problem domain where the densities of the integrals are reconstructed from the interpolation formulae that already included the problem boundary conditions.

      PubDate: 2016-12-16T09:39:01Z
       
  • An examination of evaluation algorithms for the RBF method
    • Abstract: Publication date: February 2017
      Source:Engineering Analysis with Boundary Elements, Volume 75
      Author(s): Scott A. Sarra, Samuel Cogar
      Radial Basis Function (RBF) methods are important tools for scattered data interpolation and for the solution of PDEs in complexly shaped domains. Several approaches for the evaluation of RBF methods are known. To date, the most noteworthy methods are solving a linear system in the standard RBF basis using both double and extended precision floating point arithmetic and two approaches that make a change of basis for the purpose of obtaining a better conditioned linear system. In this work the approaches are compared and contrasted for the purpose of illustrating the strengths and weakness of each method as well as to give insight into the application of each approach.

      PubDate: 2016-12-09T08:49:41Z
       
  • Thermal shock analysis of 2D cracked solids using the numerical manifold
           method and precise time integration
    • Abstract: Publication date: February 2017
      Source:Engineering Analysis with Boundary Elements, Volume 75
      Author(s): H.H. Zhang, G.W. Ma, L.F. Fan
      The numerical manifold method (NMM), combined with the precise time integration method (PTIM), is proposed for thermal shock fracture analysis. The temperature and displacement discontinuity across crack faces is naturally portrayed attributing to the cover systems in the NMM. The crack tip singularities are characterized through the use of asymptotic bases in the approximations. The discrete equations for transient thermal analysis are firstly solved with the PTIM and then the thermoelastic study is performed. With the interaction integral, the stress intensity factors are computed. Several examples are tested and the nice consistency between the present and existing results is found.

      PubDate: 2016-12-09T08:49:41Z
       
  • 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
       
  • 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
       
  • 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
       
 
 
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