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  Subjects -> ENGINEERING (Total: 2277 journals)
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ENGINEERING (1203 journals)            First | 1 2 3 4 5 6 7 | Last

Showing 401 - 600 of 1205 Journals sorted alphabetically
IET Optoelectronics     Hybrid Journal   (Followers: 1)
IET Radar, Sonar & Navigation     Hybrid Journal   (Followers: 28)
IET Renewable Power Generation     Hybrid Journal   (Followers: 10)
IET Science, Measurement & Technology     Hybrid Journal   (Followers: 2)
IET Signal Processing     Hybrid Journal   (Followers: 19)
IETE Journal of Research     Open Access   (Followers: 11)
IETE Technical Review     Open Access   (Followers: 11)
IIE Transactions     Hybrid Journal   (Followers: 1)
IIUM Engineering Journal     Open Access  
Implementation Science     Open Access   (Followers: 15)
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: 17)
Informatik-Spektrum     Hybrid Journal   (Followers: 2)
Ingeniare : Revista Chilena de Ingenieria     Open Access   (Followers: 1)
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Ingeniería Investigación y Desarrollo     Open Access   (Followers: 2)
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Ingenio Magno     Open Access   (Followers: 1)
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: 23)
International Archives of Science and Technology     Open Access  
International Communications in Heat and Mass Transfer     Hybrid Journal   (Followers: 20)
International conference KNOWLEDGE-BASED ORGANIZATION     Open Access  
International Heat Treatment and Surface Engineering     Hybrid Journal   (Followers: 5)
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: 4)
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: 18)
International Journal of Advanced Engineering Research and Science IJAERS     Open Access   (Followers: 8)
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: 3)
International Journal of Aerodynamics     Hybrid Journal   (Followers: 20)
International Journal of Air-Conditioning and Refrigeration     Hybrid Journal   (Followers: 9)
International Journal of Antennas and Propagation     Open Access   (Followers: 11)
International Journal of Applied Ceramic Technology     Hybrid Journal   (Followers: 8)
International Journal of Applied Power Engineering     Open Access   (Followers: 5)
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 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: 11)
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: 4)
International Journal of Embedded Systems     Hybrid Journal   (Followers: 5)
International Journal of Energy Optimization and Engineering     Hybrid Journal   (Followers: 5)
International Journal of Engine Research     Hybrid Journal   (Followers: 1)
International Journal of Engineering & Technology     Open Access   (Followers: 6)
International Journal of Engineering and Future Technology     Open Access  
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: 2)
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: 10)
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: 37)
International Journal of Foresight and Innovation Policy     Hybrid Journal   (Followers: 6)
International Journal of Fracture     Hybrid Journal   (Followers: 12)
International Journal of Geo-Engineering     Open Access   (Followers: 3)
International Journal of Geotechnical Engineering     Hybrid Journal   (Followers: 6)
International Journal of Grid and Utility Computing     Hybrid Journal  
International Journal of Heat and Fluid Flow     Hybrid Journal   (Followers: 35)
International Journal of Heat and Mass Transfer     Hybrid Journal   (Followers: 205)
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: 2)
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: 7)
International Journal of Manufacturing Technology and Management     Hybrid Journal   (Followers: 8)
International Journal of Marine Engineering Innovation and Research     Open Access  
International Journal of Materials and Product Technology     Hybrid Journal   (Followers: 4)
International Journal of Mathematical Education in Science and Technology     Hybrid Journal   (Followers: 11)
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: 8)
International Journal of Mobile Network Design and Innovation     Hybrid Journal   (Followers: 2)
International Journal of Multiphase Flow     Hybrid Journal   (Followers: 7)
International Journal of Nanomanufacturing     Hybrid Journal  
International Journal of Nanoscience     Hybrid Journal   (Followers: 1)
International Journal of Nanotechnology     Hybrid Journal   (Followers: 7)
International Journal of Nanotechnology and Molecular Computation     Full-text available via subscription   (Followers: 3)
International Journal of Navigation and Observation     Open Access   (Followers: 20)
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: 11)
International Journal of Optics     Open Access   (Followers: 7)
International Journal of Organisational Design and Engineering     Hybrid Journal   (Followers: 6)
International Journal of Pattern Recognition and Artificial Intelligence     Hybrid Journal   (Followers: 8)
International Journal of Pavement Engineering     Hybrid Journal   (Followers: 6)
International Journal of Physical Modelling in Geotechnics     Hybrid Journal   (Followers: 5)
International Journal of Plastics Technology     Hybrid Journal   (Followers: 2)
International Journal of Polymer Analysis and Characterization     Hybrid Journal   (Followers: 7)
International Journal of Polymer Science     Open Access   (Followers: 24)
International Journal of Precision Engineering and Manufacturing     Hybrid Journal   (Followers: 9)
International Journal of Precision Engineering and Manufacturing-Green Technology     Hybrid Journal   (Followers: 2)
International Journal of Precision Technology     Hybrid Journal   (Followers: 1)
International Journal of Pressure Vessels and Piping     Hybrid Journal   (Followers: 20)
International Journal of Production Economics     Hybrid Journal   (Followers: 14)
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: 3)
International Journal of Quantum Information     Hybrid Journal   (Followers: 4)
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: 14)
International Journal of Renewable Energy Technology     Hybrid Journal   (Followers: 9)
International Journal of Robust and Nonlinear Control     Hybrid Journal   (Followers: 5)
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: 6)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 8)
International Journal of Speech Technology     Hybrid Journal   (Followers: 8)
International Journal of Spray and Combustion Dynamics     Hybrid Journal   (Followers: 14)
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  
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International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 3)
International Journal of Technoethics     Full-text available via subscription   (Followers: 2)
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: 4)
International Journal of Thermal Sciences     Hybrid Journal   (Followers: 16)
International Journal of Thermodynamics     Open Access   (Followers: 8)
International Journal of Turbo & Jet-Engines     Hybrid Journal   (Followers: 4)
International Journal of Turbomachinery, Propulsion and Power     Open Access   (Followers: 1)
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: 6)
International Journal of Vehicle Safety     Hybrid Journal   (Followers: 6)
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: 7)

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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  [3049 journals]
  • Analytical derivation and numerical experiment of degenerate scale by
           using the degenerate kernel of the bipolar coordinates
    • Abstract: Publication date: December 2017
      Source:Engineering Analysis with Boundary Elements, Volume 85
      Author(s): Jeng-Tzong Chen, Shing-Kai Kao, Jia-Wei Lee
      Degenerate scales of an eccentric annulus and an infinite plane with two identical circular holes in the boundary integral equation method (BIEM) are analytically derived and numerically implemented in this paper. To analytically study the degenerate scale of the BIE, the closed-form fundamental solution of the two-dimensional Laplace equation, ln r, is expanded by a degenerate (separate) kernel in terms of the bipolar coordinates. It is proved that unit radius of the outer circle dominates the degenerate scale of eccentric annulus. An analytical formula of degenerate scale for the infinite plane with two identical circular boundaries was also derived at the first time. In addition, null fields of the domain and complementary domain for the ordinary and degenerate scales are both shown, respectively. Finally, comparison with available results and the BEM data are well done.

      PubDate: 2017-10-14T10:55:16Z
       
  • Scaled boundary isogeometric analysis for electrostatic problems
    • Abstract: Publication date: December 2017
      Source:Engineering Analysis with Boundary Elements, Volume 85
      Author(s): Binghan Xue, Gao Lin, Zhiqiang Hu
      The scaled boundary isogeometric analysis (SBIGA) is a novel semi-analytical technique, combing the advantages of the scaled boundary finite element method and the isogeometric analysis. In this paper, SBIGA is firstly exploited to solve electrostatic problems. According to the Laplace equation of electrostatic problems, the derivations and solutions of SBIGA equations for bounded domain and open domain problems are presented in details. A mortar method is employed to couple the solution on different subdomains, when the electrostatic problems with inhomogeneous media or complex boundaries which cannot be described by a single NURBS patch or cannot satisfy the scaling requirement in SBIGA. The mortar-based SBIGA can retain the flexibility of interface meshes compared with strong coupling methods. A condensation scheme is exploited to treat system equation in the analysis. Several numerical examples confirm the effectiveness, accuracy and convergence properties of SBIGA and the mortar-based SBIGA in solving electrostatic problems.

      PubDate: 2017-10-10T10:38:42Z
       
  • An efficient method for predicting train-induced vibrations from a tunnel
           in a poroelastic half-space
    • Abstract: Publication date: December 2017
      Source:Engineering Analysis with Boundary Elements, Volume 85
      Author(s): Shunhua Zhou, Chao He, Honggui Di, Peijun Guo, Xiaohui Zhang
      This paper presents an efficient method for the prediction of vibrations induced by underground railways in a poroelastic half-space. The proposed method accounts for both the saturated porous characteristic of the soil and the free surface effect. An analytical tunnel model, which is coupled with a train-track system, is firstly developed to calculate the dynamic response of the tunnel–soil interface in a poroelastic full-space. By assuming that the near field response of the tunnel is not affected by the existence of the free surface, vibrations of the poroelastic half-space is then calculated by the two-and-a-half-dimensional (2.5-D) boundary integral equation for saturated porous media along with the Green's function for a poroelastic half-space. Soil vibrations generated by the quasi-static and dynamic train load are presented. It is found that an increase of the soil permeability leads to a decrease of the soil displacement. A saturated soil model may be more suitable for calculating the train-induced vibration in water-rich region. Isolation effectiveness of a float slab is also investigated. The simulation results show that floating the track slab can moderately induces the ground vibration, but also causes more transmission of vibration under certain conditions.

      PubDate: 2017-10-10T10:38:42Z
       
  • Exact evaluation of hydrodynamic loads on ships using NURBS surfaces and
           acceleration potential
    • Abstract: Publication date: December 2017
      Source:Engineering Analysis with Boundary Elements, Volume 85
      Author(s): Arash Abbasnia, C. Guedes Soares
      The development of an accurate surface intersecting methodology and adaptive acceleration potential scheme, in order to precisely compute pressure on the wet surface of ships hulls, is presented. Non-Uniform Rational B-Spline (NURBS) surfaces are used to describe the ships hulls and the free surface evolutions. The intersection of free surface with ship hull is found by solving the resultant system of equations yielded from surface intersecting scheme. The pressure distribution over the exact wet surface of ship hull surface is obtained based on acceleration potential in a time domain simulation. Hence, implicit body boundary condition is applied to evaluate the time derivative of velocity potential on the hull surface in a fully nonlinear numerical wave tank. On the other hand, tangential derivatives of the velocity potential on the wet surface are approximated by B-Spline surface. Wave propagation is considered to examine the accuracy and convergence of the present solution. Motions of a Wigley hulls in linear wave are compared with experimental measurements and prior numerical solutions to verify the present numerical procedure. Also, fully nonlinear motions of a Wigley hull in nonlinear wave is simulated.

      PubDate: 2017-10-02T09:49:27Z
       
  • An efficient high order plane wave time domain algorithm for transient
           electromagnetic scattering analysis
    • Abstract: Publication date: December 2017
      Source:Engineering Analysis with Boundary Elements, Volume 85
      Author(s): G.S. Cheng, Z.H. Fan, D.Z. Ding, R.S. Chen
      An efficient high order plane wave time domain algorithm is presented for analyzing the transient scattering from three dimensional electrically large conducting objects. This method uses a set of hierarchical divergence-conforming vector basis functions to accurately represent the current distribution on the perfect electrically conducting (PEC) surface. The higher order functions can significantly reduce the number of unknowns without compromise on the accuracy. The time domain combined field integral equation (TD-CFIE) is then discretized using the hierarchical divergence-conforming vector basis functions and shifted Lagrange polynomial functions in spatial and time domain, respectively. The final matrix equation can be accelerated using the plane wave time domain (PWTD) algorithm. Finally, a parallel algorithm that can execute on a distributed-memory parallel cluster is developed, which provides an appealing avenue for analyzing the transient scattering from three-dimensional electrically large complex PEC objects. Numerical examples are given to demonstrate the accuracy and efficiency of the method.

      PubDate: 2017-10-02T09:49:27Z
       
  • Non-Euclidean distance fundamental solution of Hausdorff derivative
           partial differential equations
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Wen Chen, Fajie Wang, Bin Zheng, Wei Cai
      The Hausdorff derivative partial differential equations have in recent years been found to be capable of describing complex mechanics and physics behaviors such as anomalous diffusion, creep and relaxation in fractal media. But most research is concerned with time Hausdorff derivative models, and little has been reported on the numerical solution of spatial Hausdorff derivative partial differential equations. In this study, we derive the fundamental solutions of the Hausdorff derivative Laplace, Helmholtz, modified Hemholtz, and convection-diffusion equations via a non-Euclidean metric, called the Hausdorff fractal distance. And then the singular boundary method is used to numerically simulate the steady heat transfer governed by the Hausdorff Laplace equation in comparison with the corresponding fractional Laplacian models. Numerical experiments show the validity and applicability of the derived fundamental solution of the Hausdorff Laplace equation.

      PubDate: 2017-09-25T08:38:20Z
       
  • Transient SH-wave scattering by the lined tunnels embedded in an elastic
           half-plane
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Mehdi Panji, Bahman Ansari
      A direct half-plane time-domain boundary element method (BEM) was developed and successfully applied to analyze the transient response of ground surface in the presence of arbitrarily shaped lined tunnels, embedded in a linear elastic half-space, subjected to propagating obliquely incident plane SH-waves. To prepare the model, only the interface and inner boundary of the lining need to be discretized. The problem was decomposed into a pitted half-plane and a closed ring-shaped domain, corresponding to the substructure procedure. After computing the matrices and satisfying the compatibility as well as boundary conditions, the coupled equations were solved to obtain the boundary values. To validate the responses, a practical example was analyzed and compared with those of the published works. The results showed that the model was very simple and the accuracy was favorable. Advanced numerical results were also illustrated for single/twin circular lined tunnels as synthetic seismograms and three-dimensional frequency-domain responses. The method used in this paper is recommended to obtain the transient response of underground structures in combination with other numerical methods.

      PubDate: 2017-09-25T08:38:20Z
       
  • A mesh-free vibration analysis of strain gradient nano-beams
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Lifeng Wang, Xiaoqiao He, Yuzhou Sun, K.M. Liew
      This paper focuses on developing a mesh-free method to analyze vibrational behavior of strain gradient nano-beams. For this purpose, the paper starts with the dynamic equation of a strain gradient Euler beam, and then the moving least-square (MLS) approximation is used to construct the shape function and its second- and third-order derivatives. A mesh-free numerical simulation scheme is develop, in which the higher-order gradient of strain is directly approximated with the nodal components due to the higher-order continuity of the shape function. The reliability of the mesh-free method is illustrated by an example of the simply-supported beam. Numerical simulations are carried out to study the small scale effect on both natural frequencies and vibration mode shapes of a single-walled carbon nanotube (SWCNT) which can be modeled as a nano-beam. The results of the mesh-free analysis are in good agreement with the theoretical results in analyzing the simply-supported SWCNT. The difference of natural frequency between that predicted by the strain gradient elastic beam and the classical beam rises with the increasing of the mode order and decreasing of the length.

      PubDate: 2017-09-25T08:38:20Z
       
  • A smoothed finite element method for exterior Helmholtz equation in two
           dimensions
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Yingbin Chai, Zhixiong Gong, Wei Li, Tianyun Li, Qifan Zhang
      In this work, a smoothed finite element method (SFEM), in which the gradient smoothing technique (GST) from meshfree methods is incorporated into the standard Galerkin variational equation, is proposed to handle the acoustic wave scattering by the obstacles immersed in water. In the SFEM model, only the values of shape functions, not the derivatives at the quadrature points, are required and no coordinate transformation is needed to perform the numerical integration. Due to the softening effects provided by the GST, the original “overly-stiff” FEM model has been properly softened and a more appropriate stiffness of the continuous system can be obtained, then the numerical dispersion error for the acoustic problems is decreased conspicuously and the quality of the numerical solutions can be improved significantly. To tackle the exterior Helmholtz equation in unbounded domains, we use the well-known Dirichlet-to-Neumann (DtN) map to guarantee that there are no spurious reflecting waves from the far field. Numerical tests show that the present SFEM cum DtN map (SFEM-DtN) works well for exterior Helmholtz equation and can provide better solutions than standard FEM.

      PubDate: 2017-09-25T08:38:20Z
       
  • Smoothed finite element methods (S-FEMs) with polynomial pressure
           projection (P3) for incompressible solids
    • Abstract: Publication date: Available online 14 September 2017
      Source:Engineering Analysis with Boundary Elements
      Author(s): Chen Jiang, Xu Han, G.R. Liu, Zhi-Qian Zhang, Gang Yang, Guang-Jun Gao
      In this paper, we apply a polynomial pressure projection (P3) formulation in the smoothed finite element methods (S-FEMs) to stabilize the pressure solutions for nearly-incompressible and incompressible solids. The P3 technique, using equal-order approximation, is implemented in the cell-based S-FEM (CS), edge-based S-FEM (ES) and node-based S-FEM (NS) all using simplest triangular element. The proposed P3-S-FEMs (P3-CS, P3-ES, P3-NS) are supposed to address issues of volumetric locking and pressure oscillation using equal-order displacement-pressure approximations. Numerical examples are employed to verify and check performances of the proposed methods, demonstrating that all the P3-S-FEMs are fully volumetric locking free. Except for P3-NS, P3-CS and P3-ES are without pressure oscillation. Another founding of P3-S-FEMs is that P3 technique can further soft the whole system besides S-FEMs. The excellent properties of these S-FEMs for compressible materials are still maintained by P3-S-FEMs, such as the insensitiveness to mesh distortion. The unique upper bound property of NS-FEM is also inherited by P3-NS. In the performance studies, P3-ES stands out on accuracy, convergence and efficiency among three proposed methods.

      PubDate: 2017-09-18T09:02:45Z
       
  • Galerkin boundary integral formulation for axisymmetric stokes flow
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): A. Xue, E. Graciani, L.J. Gray, V. Mantič, Maria Garzon
      A Galerkin boundary integral formulation for 3D axisymmetric Stokes flow is presented. The singular integrals are evaluated by splitting the complicated Green’s function kernels into a singular term that can be integrated analytically, plus a term for which Gauss quadrature provides sufficient accuracy. As in a previous axisymmetric Laplace implementation, the treatment of the additional on-axis singularity is aided by employing a modified Galerkin weight function, and a similar splitting method is then employed to handle this singularity. The target application of the Stokes algorithm is to model the breakup of one viscous fluid enclosed inside a second, and this two fluid problem can be formulated in terms of a single boundary integral equation along the interface. The Galerkin form for this equation is derived herein.

      PubDate: 2017-09-12T08:45:40Z
       
  • A boundary element method for a class of elliptic boundary value problems
           of functionally graded media
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Nasaruddin Salam, Amiruddin Haddade, David L. Clements, Moh. Ivan Azis
      A Boundary Element Method (BEM) is derived for obtaining solutions to a class of elliptic boundary value problems (BVPs) of functionally graded media (FGM). Some particular examples are considered to illustrate the application of the BEM.

      PubDate: 2017-09-12T08:45:40Z
       
  • Radial basis functions methods for boundary value problems: Performance
           comparison
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Lihua Wang
      We present in this paper comparisons on the performances among five typical radial basis functions methods, namely radial basis collocation method (RBCM), radial basis Galerkin method (RBGM), compactly supported radial basis collocation method (CSRBCM), compactly supported radial basis Galerkin method (CSRBGM), and finite subdomain radial basis collocation method (FSRBCM), for solving problems arising from engineering industries and applied sciences. Numerical comparison results demonstrate that the RBCM and FSRBCM possess high accuracy and superior convergence rates in which the FSRBCM particularly attains higher accuracy for problems with large gradients. The FSRBCM, CSRBCM and RBCM are computationally efficient while the CSRBCM, CSRBGM and FSRBCM can greatly improve the ill-conditioning of the resultant matrix. In conclusion, its advantages on high accuracy; exponential convergence; well-conditioning; and effective computation make the FSRBCM a first-choice among the five radial basis functions methods.

      PubDate: 2017-09-12T08:45:40Z
       
  • A novel approach to solve inverse heat conduction problems: Coupling
           scaled boundary finite element method to a hybrid optimization algorithm
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Sassan Mohasseb, Mohsen Moradi, Tahmineh Sokhansefat, Farshad kowsari, Alibakhsh Kasaeian, Omid Mahian
      Scaled boundary finite element method (SBFEM) has proved its abilities in problems with singularities successfully. In this work, the coupling of SBFEM and a hybrid optimization algorithm is employed to determine unknown heat flux in the transient heat conduction problems. The genetic algorithm (GA) is a stochastic method which solves problems considering a large number of generations, while the deterministic methods such as sequential quadratic programming (SQP), which are sensitive to the initial points, can solve problems faster. Combining GA, as the main optimizer, and SQP can lead to lower computational time. Herein, a square plate is considered as the case study. The inverse analysis is accomplished by utilizing the transient temperature data from direct solution. The difference between the calculated and the known values of temperature at four points within the plate is considered as the objective function, and the heat fluxes on the upper side of the plate are considered as the design variables. As a result, the exact value of the heat fluxes is obtained using this method. This new approach, in which the SBFEM as a meshless solver is combined with the hybrid GA-SQP as the optimizer, highlights its potentials in solving inverse problems.

      PubDate: 2017-09-12T08:45:40Z
       
  • An integrated SPH-polyhedral DEM algorithm to investigate hydraulic
           stability of rock and concrete blocks: Application to cubic armours in
           breakwaters
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Mohammad Sarfaraz, Ali Pak
      In this paper, a combination of the Lagrangian meshfree method of SPH and Polyhedral DEM is presented to simulate the interaction between the free surface of water and solid objects possessing sharp edges and flat surfaces, such as armour units of breakwaters. Both SPH and DEM schemes are validated successfully against experimental data. The numerical scheme is utilized to inspect the stability of concrete cubic armours in rubble-mound breakwaters through systematic analyses with various geometrical parameters and environmental conditions. The numerical results regarding the required dimensions of the cubic blocks for providing stability of the armour units under the wave attack are compared with the existing empirical formulae. It is shown that armour units located at the still water level are more exposed to damage due to wave attack. The proposed numerical technique proved to be accurate and therefore it can be used for designing the armour blocks of the sloping breakwaters and also for inspecting the possible level of damage to the system of armour units.

      PubDate: 2017-09-06T08:20:58Z
       
  • The frequency averaged normal-derivative integral equation to predict
           frequency averaged quadratic pressure radiated from structures
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Honglin Gao, Sheng Li, Chunxia Meng
      Frequency averaged normal-derivative Helmholtz integral equation is proposed to get robust predictions of the frequency averaged quadratic pressure (FAQP) radiated from the structures at medium and high frequencies. The non-uniqueness problem of frequency averaged Helmholtz integral equation and frequency averaged normal-derivative Helmholtz integral equation is overcome by the coupling method combining these two integral equations. The numerical examples are given to demonstrate the versatility of the frequency averaged normal-derivative Helmholtz integral equation and the coupling method.

      PubDate: 2017-09-06T08:20:58Z
       
  • Improved complex variable moving least squares approximation for
           three-dimensional problems using boundary integral equations
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Xiaolin Li, Shuling Li
      The improved complex variable moving least squares approximation is an efficient method to generate meshless approximation functions. In the past, the approximation has been used only for 2D problems. In this paper, the approximation is developed to solve 3D problems. Theoretical error estimation of the approximation is given. Then, incorporating the approximation into boundary integral equations, a symmetric and boundary-only meshless method, the complex variable Galerkin boundary node method, is developed and analyzed theoretically for 3D potential, Helmholtz and Stokes problems. Numerical results demonstrate the accuracy and efficiency of the developed method.

      PubDate: 2017-09-06T08:20:58Z
       
  • Extending Incompressible SPH framework for simulation of axisymmetric
           free-surface flows
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Gourabananda Pahar, Anirban Dhar, Md Rushdie Ibne Islam
      Dynamics of a Newtonian fluid in a cylindrical symmetric domain can be conceptualized as axisymmetric flow. Full-scale 3D simulation of such problems requires large computational overhead. A new divergence-free Axisymmetric Incompressible Smoothed Particle Hydrodynamics (AxISPH) framework is proposed for modeling of Newtonian fluid flow with free-surface. The formulation employs the concept of variable axisymmetric volume based on current particle position to incorporate symmetry around the central axis. The framework utilizes a semi-implicit two-step approach to obtain hydrodynamic variables and minimizes errors in particle position. Laplace and gradient operators are modified to incorporate axisymmetric nature. A radial dam-break flow has been simulated with the proposed model and compared with three-dimensional ISPH result.

      PubDate: 2017-09-06T08:20:58Z
       
  • Structured mesh refinement in MLS-based numerical manifold method and its
           application to crack problems
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Feng Liu, Kaiwen Xia
      The numerical manifold method (NMM) is suitable for both continuity and discontinuity problems due to its two cover systems, namely the mathematical cover and the physical cover. However, the use of these two cover systems makes it difficult to implement local mesh refinement in conventional NMM. In this paper, a structured mesh refinement is proposed for crack problems within the framework of MLS-based NMM. In order to balance both accuracy and efficiency, an eccentric domain of influence is suggested near the transition region, where the domain size is determined by surrounding elements. The visibility criterion used in element-free Galerkin method is introduced to describe the discontinuity near the crack tip. The main advantage of the proposed method is that it can solve complex crack problems straightforwardly without introducing any extra degree of freedom. Several examples are tested to demonstrate the effectiveness of the proposed method for crack problems.

      PubDate: 2017-09-06T08:20:58Z
       
  • A hybrid improved complex variable element-free Galerkin method for
           three-dimensional potential problems
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): H. Cheng, M.J. Peng, Y.M. Cheng
      Combining the dimension splitting method with the improved complex variable element-free Galerkin method, a hybrid improved complex variable element-free Galerkin (H-ICVEFG) method is presented for three-dimensional potential problems. Using the dimension splitting method, a three-dimensional potential problem is transformed into a series of two-dimensional ones which can be solved with the improved complex variable element-free Galerkin (ICVEFG) method. In the ICVEFG method for each two-dimensional problem, the improved complex variable moving least-square (ICVMLS) approximation is used to obtain the shape functions, and the penalty method is used to apply the essential boundary conditions. Finite difference method is used in the one-dimensional direction. And Galerkin weak form of three-dimensional potential problem is used to obtain the final discretized equations. Then the H-ICVEFG method for three-dimensional potential problems is presented. Four numerical examples are given to show that the new method has higher computational efficiency.

      PubDate: 2017-09-06T08:20:58Z
       
  • Propulsion of an active flapping foil in heading waves of deep water
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): G.D. Xu, W.Y. Duan, B.Z. Zhou
      The propulsion of a flapping foil in heading waves has been investigated through the velocity potential theory. The trajectory of the flapping foil is prescribed with the combined sinusoidal heave and pitch motions. Boundary element method is introduced to solve the boundary value problem and a time stepping scheme is adopted to simulate the interaction of the foil and Stokes waves of infinite water-depth. The nonlinear free surface boundary conditions are imposed when updating the free surface. The effects of the frequency difference between foil motion and waves have been investigated. When the encountered wave frequency equals the flapping frequency, hydrodynamic performance of the flapping foil can be enhanced significantly.

      PubDate: 2017-09-06T08:20:58Z
       
  • On the optimal shape parameters of distinct versions of RBF meshless
           methods for the bending analysis of plates
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Behzad V. Farahani, Jose Berardo, Jorge Belinha, A.J.M. Ferreira, Paulo J. Tavares, P.M.G.P. Moreira
      This study intends to computationally analyze single-layer plates. Reissner–Mindlin plate deformation theory was combined with the radial basis function (RBF) meshless method. Considering the first order shear deformation theory, the RBF meshless method formulation for isotropic plates analysis is presented. According to the motion equations in terms of displacement for isotropic homogeneous laminates, non-zero laminate stiffness is determined. Transverse displacement results are evaluated for various thickness values where the plate is simply supported in all edges. In this work, it is also shown that Wendland's RBF formulation with optimal values of the shape parameter formulation using several mesh densities produces deflections of single-layer laminate plates agreeing well with analytical solutions. The obtained RBF solution proves that the supporting numerical methodology is efficient and robust.

      PubDate: 2017-09-06T08:20:58Z
       
  • An enhanced octree polyhedral scaled boundary finite element method and
           its applications in structure analysis
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Degao Zou, Kai Chen, Xianjing Kong, Jingmao Liu
      In this paper, an enhanced octree polyhedral scaled boundary finite element method (SBFEM) is proposed in which arbitrary convex polygon (pentagon, hexagon, heptagon, octagon etc.) can be directly served as boundary face elements. The presented method overcomes the existing SBFEM's limitation that boundary face is strictly restricted to be a quadrangle or triangle. The conforming shape functions are constructed using a polygon mean-value interpolation scheme for polyhedral face. A highly efficient octree mesh generation technology is introduced to accelerate the progress of pre-treatment, wherein the mesh information can be directly used in the enhanced SBFEM. The accuracy of the proposed method is first verified using a beam under shear and torsion load. Another three more complicated geometries including a nuclear power plant structure, as well as two sculptures named Terra-Cotta Warriors and Sioux Falls Church are presented to demonstrate the application and robustness of the proposed method. The new method possesses appealing versatility and offers a swift adaptive capacity in mesh generation, which can provide a powerful technique for the simulation of complex geometries, rapid-design analysis and multi-scale problems.

      PubDate: 2017-09-06T08:20:58Z
       
  • Element-free Galerkin method for numerical simulation of sediment
           transport equations on regular and irregular distribution of nodes
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Ali Rahmani Firoozjaee, Mostafa Sahebdel
      In this paper, the numerical simulation of the bed-load sediment transport using Element-Free Galerkin (EFG) method is presented. The governing equations of this model include shallow water equations for the hydraulic behaviour, Exner equation for morphodynamic variations, and Grass model for solid discharge. The governing equations are formulated for the coupled approach. The problem is solved using EFG meshfree method, in which the problem domain is represented by a set of arbitrarily distributed nodes; there is no need to use meshes, elements, or any other node connectivity information for field variable interpolation. The EFG method is based on moving least-squares (MLS) shape functions originated in scattered data fitting. Finally, to assess the ability and the efficiency of the EFG method, several benchmark examples on regular and irregular distribution of nodes are investigated and the results are compared with those of previously published works.

      PubDate: 2017-09-06T08:20:58Z
       
  • Improved numerical manifold method (iNMM)—An extra-DOF free and
           interpolating NMM with continuous nodal stress
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Guohua Zhang, Yongtao Yang, Hao Wang
      As a partition of unity method (PUM), the numerical manifold method (NMM) is capable of constructing global approximation by simply multiplying PU function with local approximation. In order to enhance accuracy, high order polynomials can be specified as local approximation. This, however, will hinder the engineering application of NMM by its ill conditioning of the global stiffness matrix. In this study, an improved NMM (iNMM) without extra degree of freedoms (DOFs) is developed. Without the extra DOFs, the resulting global stiffness becomes linear independent. In addition, the stresses are continuous at all nodes. Numerical studies show the iNMM's excellent accuracy.

      PubDate: 2017-09-06T08:20:58Z
       
  • Numerical analysis of an advective diffusion domain coupled with a
           diffusive heat source
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Roberto Pettres, Luiz Alkimin de Lacerda
      This paper presents a formulation of the boundary element method (BEM) for the study of heat diffusion and advective effect in isotropic and homogeneous media. The proposed formulation has a time independent fundamental solution obtained from the two-dimensional Laplace equation. Consequently, the formulation is called D-BEM since it has domain integrals in the basic integral equation. The first order time derivative that appears in the integral equations is approximated by a backward finite difference scheme. Homogeneous subregions are considered in the analysis in a specific model simulating a nonuniform flow passing by a circular obstacle under internal heat generation. Results from numerical models are compared with the available analytical solutions. The correlation estimator R 2 is employed to validate the numerical model and to demonstrate the accuracy of the proposed formulation.

      PubDate: 2017-09-06T08:20:58Z
       
  • Dynamic crack analysis in piezoelectric solids under time-harmonic
           loadings with a symmetric Galerkin boundary element method
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): M. Wünsche, J. Sladek, V. Sladek, C. Zhang, F. García-Sánchez, A. Sáez
      This paper presents the dynamic crack analysis in two-dimensional (2D) and linear piezoelectric composites. Stationary cracks in infinite and finite piezoelectric solids subjected to different time-harmonic loadings are investigated. A symmetric Galerkin boundary element method (SGBEM) is developed for this purpose. The frequency-domain fundamental solutions for linear piezoelectric solids are utilized. The double boundary integrals are computed analytically for straight elements to enhance the efficiency of the present SGBEM. Non-linear electrical crack-face boundary conditions are applied to take the limited electrical permeability of the crack into account. Numerical examples are presented and discussed to show the accuracy of the presented frequency-domain SGBEM and the influences of the coupled fields on the dynamic field intensity factors.

      PubDate: 2017-09-06T08:20:58Z
       
  • The method of fundamental solution for elastic wave scattering and dynamic
           stress concentration in a fluid-saturated poroelastic layered half-plane
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Zhongxian Liu, Jianwen Liang, Chengqing Wu, Ruibin Zhao, Yan Li
      A meshless method based on the method of fundamental solution (MFS) is developed to solve elastic-wave scattering and dynamic stress concentration in a fluid-saturated poroelastic layered half-plane, by utilizing the line sources of cylindrical PI, PII, and SV waves in a poroelastic layered half-plane. The numerical accuracy and stability of the MFS is verified by examining the boundary conditions and comparison with other methods. Subsequently, the amplification effects on displacement, surface hoop stress and fluid pore pressure around a cavity in a three-layered poroelastic half-plane are investigated. Numerical results indicate that the scattering characteristics strongly depend on parameters including the incident frequency and angle, soil-layer porosity and boundary drainage condition. The amplification effects of a cavity in the poroelastic layered half-plane appear to be more significant than the corresponding case of a homogenous half-plane. The amplitude of the fluid pore pressure on the surface of the cavity is amplified up to five times that of the free field, which also considerably aggravates the dynamic stress concentration around the cavity.

      PubDate: 2017-09-06T08:20:58Z
       
  • Combined mesh free method and mode matching approach for transmission loss
           predictions of expansion chamber silencers
    • Abstract: Publication date: November 2017
      Source:Engineering Analysis with Boundary Elements, Volume 84
      Author(s): Z. Fang, C.Y. Liu
      A coupled method (abbreviated here as the MFMM method) that combines the mesh free (MF) method and mode matching (MM) approach is introduced to predict the transmission loss (TL) of expansion chamber silencers. The Hermite radial point interpolation collocation (HRPIC) method is employed to solve the 2-D eigen equation of silencer sections. Then the mode matching method is used to calculate the transmission loss. The eigenvalues predictions of circular cross section from the present method exhibit desirable precision comparison with analytical results. Additionally, the effects of size of influence domain, number of computational nodes and shape parameters of radial basis functions on the calculation accuracy are evaluated. TL calculations of four typical expansion chambers with extended inlet and outlet are presented to valid the computational accuracy and efficiency of the proposed combined method.

      PubDate: 2017-09-06T08:20:58Z
       
  • Subdomain BEM formulations for the solution of bio-heat problems in
           biological tissue with melanoma lesions
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): J. Iljaž, L.C. Wrobel, M. Hriberšek, J. Marn
      The main objective of the research presented in this paper is the development of efficient subdomain BEM solvers for the solution of steady-state and transient bio-heat problems in biological tissue, particularly involving melanoma of different sizes such as Clark II and IV. The short-term goal of the work is to investigate which of the numerical schemes implemented here produces the highest accuracy and efficiency, as a first step towards the long-term goal of solving inverse bio-heat problems for tumour diagnostics, i.e. the detection of tumour size and tumour parameters. The numerical results show that quadratic elements produce high accuracy with coarser meshes, and are thus more computationally efficient for this type of problem. It was also found that, for transient problems, a BEM formulation using the time-dependent fundamental solution of the diffusion equation was more efficient than the use of the fundamental solution of the Laplace equation with a finite difference time discretisation scheme, as much larger time steps could be used for the same accuracy. This work proposes that the subdomain BEM with quadratic elements and a time-dependent fundamental solution provides high accuracy and reduced computational time, and is thus indicated for the inverse analysis of bio-heat problems.

      PubDate: 2017-08-31T08:06:06Z
       
  • High regularity partition of unity for structural physically non-linear
           analysis
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): D.C.C. Pinheiro, F.B. Barros, R.L.S. Pitangueira, S.S. Penna
      Meshfree techniques, such as hp-Clouds and Element Free Galerkin Methods, have been used as attractive alternatives to finite element method, due to the flexibility in constructing conforming approximations. These approximations can present high regularity, improving the description of the state variables used in physically non-linear problems. On the other hand, some drawbacks can be highlighted, as the lack of the Kronecker-delta property and numerical integration problems. These drawbacks can be overcome by using a Ck, k arbitrarily large, partition of unity (PoU) function, built over a finite element mesh, but with the approximate characteristic of the meshfree methods. Here, this procedure is for the first time investigated to simulate the non-linear behavior of structures with quasi-brittle materials. The smeared crack model is adopted and numerical results, obtained with different kinds of polynomial enrichments, are compared with the experimental results.

      PubDate: 2017-08-31T08:06:06Z
       
  • Pipe flow of a magnetizable fluid in rectangular cavities under magnetic
           sources
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): P. Senel, M. Tezer-Sezgin
      In this paper, the fully developed flow of an electrically non-conducting, viscous, incompressible, magnetizable fluid is investigated in rectangular pipes with square or rectangular cross-sections under the effect of spatially varying magnetic field. Magnetic field is generated by multiple wires carrying electric current that pass below and above along the pipe. Thus, the problem is reduced to the 2D flow of a magnetizable fluid in the cross-section of the pipe (cavity). Governing equations are solved in terms of the velocity and the pressure of the fluid. Stream function and axial velocity profiles are also presented. The dual reciprocity boundary element method (DRBEM) is applied iteratively in obtaining numerical results. The flow behavior is approximated with a small computational expense due to the boundary only nature of DRBEM. The numerical results reveal that multiple point magnetic sources significantly influence and control the flow in cavities.

      PubDate: 2017-08-31T08:06:06Z
       
  • A local meshless method based on the finite collocation and local integral
           equations method for delay PDEs
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): Fariba Takhtabnoos, Ahmad Shirzadi
      A local meshless method based on the finite collocation, local radial basis function (RBF) and MLPG method is proposed for solving the 2D Delay partial differential equations. In fact, instead of collocation of governing equations in the finite collocation method, we propose the use of local weak form of governing equations on the local stencils. The method is used for the numerical solutions of the 2D delay partial differential equations (PDEs). Two delay and one nonlinear multidelay parabolic PDEs are solved as test problems and the comparisons of the results reveal the effectiveness of the method.

      PubDate: 2017-08-31T08:06:06Z
       
  • An efficient numerical technique for solution of two-dimensional cubic
           nonlinear Schrödinger equation with error analysis
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): Elyas Shivanian, Ahmad Jafarabadi
      In this paper, the spectral meshless radial point interpolation (SMRPI) technique is applied to the solution of two-dimensional cubic nonlinear Schrödinger equations. Firstly, we obtain a time discrete scheme by approximating time derivative via a finite difference formula, then we use the SMRPI approach to approximate the spatial derivatives. This method is based on a 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 act as basis functions in frame of SMRPI. In the current work, the thin plate splines (TPS) are used as the basis functions and in order to eliminate the nonlinearity, a simple predictor-corrector (P-C) scheme is performed. We prove that the time discrete scheme is unconditionally stable and convergent in time variable using the energy method. We show that convergence order of the time discrete scheme is O ( δ t ) . The aim of this paper is to show that the SMRPI method is suitable for the treatment of the nonlinear Schrödinger equations. Also, the SMRPI has less computational complexity than the other methods that have already solved this problem. The results of numerical experiments are compared with analytical solution to confirm the accuracy and efficiency of the presented scheme.

      PubDate: 2017-08-31T08:06:06Z
       
  • Iterative boundary element method for crack analysis of two-dimensional
           piezoelectric semiconductor
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): QiaoYun Zhang, CuiYing Fan, GuangTao Xu, MingHao Zhao
      Based on the well-developed boundary element methods for piezoelectric media and conductors, we present an iterative boundary element method to solve the boundary value problems in two-dimensional piezoelectric semiconductors (PSCs). The proposed method is verified by analyzing a piezoelectric semiconductor plate under multi-field load. Two typically important boundary value problems, a hole and a crack, are studied in PSC plates by using the proposed method. The stress concentration near the edge of an elliptical hole in a finite piezoelectric semiconductor plate is studied by using the single-domain boundary element method. Also, by using the sub-domain boundary element method, we analyzed how the mechanical load, electrical load, electric current density, and initial electron density affected the stress, electric displacement and electric current intensity factors near the crack tip.

      PubDate: 2017-08-31T08:06:06Z
       
  • On solving free surface problems in layered soil using the method of
           fundamental solutions
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): Jing-En Xiao, Cheng-Yu Ku, Chih-Yu Liu, Chia-Ming Fan, Weichung Yeih
      This paper presents the numerical solutions of free surface seepage flow in layered soil using the method of fundamental solutions (MFS). The numerical solutions are approximated by a set of fundamental solutions of the two-dimensional Laplace equation which are expressed in terms of sources located outside the domain of the problem. The unknown coefficients in the linear combination of the fundamental solutions which are accomplished by collocation imposing the boundary condition at a finite number of points can then be solved. To deal with the seepage problems of layered soil profiles, the domain decomposition method was adopted so that flux conservation and the continuity of pressure potential at the interface between two consecutive layers can be considered in the numerical model. The validity of the model is established for a number of test problems, including seepage problems in a rectangular dam, a trapezoidal dam, and an earth dam, by comparing numerical results with those from other methods. Application examples were also carried out. The results reveal that the proposed method based on the MFS has great numerical stability for solving seepage flow with nonlinear free surface in layered heterogeneous soil even with large contrasts in the hydraulic conductivity.

      PubDate: 2017-08-31T08:06:06Z
       
  • The MFS for the identification of a sound-soft interior acoustic scatterer
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): A. Karageorghis, D. Lesnic, L. Marin
      We employ the method of fundamental solutions (MFS) for detecting a sound-soft scatterer surrounding a host acoustic homogeneous medium due to a given point source inside it. The measurements are taken inside the medium and, in addition, are contaminated with noise. The MFS discretization yields a nonlinear constrained regularized minimization problem which is solved using standard software. The results of several numerical experiments are presented and discussed.

      PubDate: 2017-08-31T08:06:06Z
       
  • An adaptive meshless parameterization for full waveform inversion
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): Franciane Conceição Peters, Edivaldo Figueiredo Fontes Junior, Webe João Mansur, Djalma Manoel Soares Filho, Cid da Silva Garcia Monteiro, Pedro Carvalho
      Full waveform inversion is a technique to recover images of the subsurface using data from a seismic survey. Nonlinearity, ill-posedness, presence of noise in data, a large number of parameters, different kinds of parameters, and limitations of data are some of the factors that contribute to instabilities of the solution. One of the strategies to regularize the solution is a suitable choice of parameterization. Depending on the parameterization strategy, the solution is searched in a space with certain features, for instance, smoothness, that may be convenient to the problem. Furthermore, a parameterization that can represent well the solution with a reduced number of parameters may be robust due to the limited number of degrees of freedom. Here we show an adaptive meshless parameterization methodology for full waveform inversion, which may also be useful for other inverse problems. The parameterization is based on a meshless technique and uses Wendland’s functions as basis functions to an interpolation. As a meshless method, it is very flexible, then the spatial distribution of the unknowns can be non-uniform, allowing focusing on certain areas or automatically improving the quality of the image near the discontinuities of a velocity model. With some numerical experiments of acoustic inversion of synthetic data, we show that the parameterization methodology described here can represent complex velocity models and that, with a reduced number of unknowns, the inversion process behaves better than the standard parameterization with blocks. We also show that the adaptive meshless parameterization has a significant regularization effect, avoiding non-natural patterns and prioritizing smooth images.

      PubDate: 2017-08-31T08:06:06Z
       
  • Scalable topology optimization with the kernel-independent fast multipole
           method
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): Igor Ostanin, Ivan Tsybulin, Mikhail Litsarev, Ivan Oseledets, Denis Zorin
      The paper presents a new method for shape and topology optimization based on an efficient and scalable boundary integral formulation for elasticity. To optimize topology, our approach uses iterative extraction of isosurfaces of a topological derivative. The numerical solution of the elasticity boundary value problem at every iteration is performed with the boundary element formulation and the kernel-independent fast multipole method. Providing excellent single node performance and scalable parallelization, our method is among the fastest optimization tools available today. The performance of our approach is studied on few illustrative examples, including the optimization of engineered constructions for the minimum compliance and the optimization of the microstructure of a metamaterial for the desired macroscopic tensor of elasticity.

      PubDate: 2017-08-31T08:06:06Z
       
  • The MFS versus the Trefftz method for the Laplace equation in 3D
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): Hui Lv, Fang Hao, Yong Wang, C.S. Chen
      The method of fundamental solutions (MFS) and the Trefftz method are two powerful boundary meshless methods for solving boundary value problems governed by homogeneous partial differential equations. High accuracy can be obtained when we employ these two methods to solve equations with harmonic boundary conditions. However, dealing with equations with non-harmonic boundary conditions in irregular domains remains a challenge. Despite the long history of these two methods, each one has its disadvantages in numerical implementation. Recent advances in the Trefftz method using the multiple scale technique has made significant improvement in reducing the condition number. As a result, the Trefftz method has become more effective for solving challenging problems. Meanwhile, there has also been progress in selecting the source points in the MFS using the Leave-One-Out Cross Validation (LOOCV) method. In this paper, we propose a simple and yet effective approach to further improve the selection of source points of the MFS in 3D. Equipped with these new techniques, we compare these two methods for solving the Laplace equation with non-harmonic boundary conditions in complicated irregular domains in 3D. In this paper, we only consider the Trefftz method with cylindrical basis functions.

      PubDate: 2017-08-31T08:06:06Z
       
  • Smoothed particle hydrodynamics with kernel gradient correction for
           modeling high velocity impact in two- and three-dimensional spaces
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): Z.L. Zhang, M.B. Liu
      High velocity impact (HVI) is associated with large deformations of structures, phase transition of materials, big craters and possible flying debris. It is thus challenging for conventional numerical methods to well capture the major physics of HVI problems. This paper presents the development of an improved smoothed particle hydrodynamics (SPH) method with kernel gradient correction (KGC) technique and the original application of the improved SPH method to modeling high velocity impact problems in two-dimensional and three-dimensional spaces. The SPH method with KGC is first validated by the 3D Taylor-Bar-Impact (TBI) test with Armco iron and OFHC copper. It is demonstrated that the obtained results agree well with experimental observations and with existing numerical results. The improved SPH method is then used to model a hypervelocity impact problem with an aluminum sphere impacting onto an aluminum plate in two- and three-dimensional spaces. It is shown that the presented SPH method can qualitatively and quantitatively model the HVI problem with main physics well captured. It is also demonstrated that the presented SPH method can reproduce experimental observations better than other numerical approaches, including the characteristic shape and evolution of the debris cloud as well the particle distribution.

      PubDate: 2017-08-31T08:06:06Z
       
  • NURBS-enhanced boundary element method based on independent geometry and
           field approximation for 2D potential problems
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): Wei Zhou, Biao Liu, Qiao Wang, Yonggang Cheng, Gang Ma, Xiaolin Chang, Xudong Chen
      Non-uniform rational B-spline (NURBS) in Isogeometric analysis (IGA) is coupled with the boundary element method (BEM) for 2D potential problems in this paper. The geometry and field are usually approximated by the same basis functions in IGA, such as the B-spline or the NURBS basis functions. In the proposed method, these two kinds of approximation are performed independently, i.e. the geometry is reproduced by the NURBS basis functions while the field is approximated by the traditional Lagrangian basis functions which are used in the conventional BEM. The proposed method has the advantage that the geometry can be reproduced exactly at all stages in IGA methods. Actually, one can use the computer aided design (CAD) software or NURBS library to perform the operations related to the geometry. The field approximation is performed in parameter space and separated from the geometry. Thus, it can be implemented easily as the conventional BEM since most algorithms for BEM can be applied directly, such as the methods for treatment of the singular integrals, and the boundary conditions can be imposed directly. Numerical examples have demonstrated the accuracy of the proposed method.

      PubDate: 2017-08-31T08:06:06Z
       
  • An extension of the singular boundary method for solving two dimensional
           time fractional diffusion equations
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): Azim Rivaz, Farzane Yousefi
      In this paper, singular boundary method (SBM) in conjunction with the dual reciprocity method (DRM) is extended to the solution of constant and variable order time fractional diffusion equations (TFDEs). In this procedure, finite difference method breaks down the time domain and reduces the time fractional diffusion equation into a sequence of boundary value problems in inhomogeneous Helmholtz-type equations. Then SBM-DRM is applied to space semi-discretization of these types of equations, in a two step process. First, DRM, which is a popular meshless method based on radial basis functions (RBFs), is applied to obtain the particular solution. After evaluating the particular solution, singular boundary method can be employed to evaluate the homogeneous solution. To consider the accuracy and efficiency of the presented method, some benchmark problems subjected to the Dirichlet and Neumann boundaries are examined on regular and irregular geometries.

      PubDate: 2017-08-31T08:06:06Z
       
  • Stress calculation and optimization in composite plates with holes based
           on the modified integral equation method
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): Olesya Maksymovych, Oleksandr Illiushyn
      The integral equations are written for multiple connected anisotropic plates in a simple form based on the simple dependencies between the Lekhnitskii complex potentials and stress and strain. The numerical method for solving integral equations is developed by the mechanical quadrature method for systems of holes, which takes into account their eigen-solutions. Simplicity, precision of the approach and stability of obtained algebraic equations is illustrated in determination of hole shapes with low stress concentration; study of high stress concentration at slit of arbitrary width (additionally used asymptotic method); calculation of the stress with controlled accuracy for a large number of holes.

      PubDate: 2017-08-31T08:06:06Z
       
  • Nested equivalence source approximation with adaptive group size for
           multiscale simulations
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): Mengmeng Li, Dazhi Ding, Jipeng Li, Rushan Chen
      A nested equivalence source approximation (NESA) of the electric field integral equation with adaptive octree is explored for multiscale problems in this paper. The NESA low rank approximation formulation previously for far coupling groups with uniform size is derived for coupling groups with adaptive size, while preserves the kernel free and multiscale property. With the proposed adaptive group decomposition, reasonable separation of near and far region can be obtained. Numerical tests of the conformal and non-conformal multiscale electromagnetic simulation to show the validity of the adaptive NESA.

      PubDate: 2017-08-31T08:06:06Z
       
  • Micro-structured materials: Inhomogeneities and imperfect interfaces in
           plane micropolar elasticity, a boundary element approach
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): Elena Atroshchenko, Jack S. Hale, Javier A. Videla, Stanislav Potapenko, Stéphane P.A. Bordas
      In this paper we tackle the simulation of microstructured materials modelled as heterogeneous Cosserat media with both perfect and imperfect interfaces. We formulate a boundary value problem for an inclusion of one plane strain micropolar phase into another micropolar phase and reduce the problem to a system of boundary integral equations, which is subsequently solved by the boundary element method. The inclusion interface condition is assumed to be imperfect, which permits jumps in both displacements/microrotations and tractions/couple tractions, as well as a linear dependence of jumps in displacements/microrotations on continuous across the interface tractions/couple traction (model known in elasticity as homogeneously imperfect interface). These features can be directly incorporated into the boundary element formulation. The BEM-results for a circular inclusion in an infinite plate are shown to be in an excellent agreement with the analytical solutions. The BEM-results for inclusions in finite plates are compared with the FEM-results obtained with FEniCS.

      PubDate: 2017-08-31T08:06:06Z
       
  • A meshless complex variable Galerkin boundary node method for potential
           and Stokes problems
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): Yaozong Tang, Xiaolin Li
      In this study, combining the boundary integral equations (BIEs) with the complex variable moving least squares (CVMLS) approximation, a symmetric and boundary-only meshless method, the complex variable Galerkin boundary node method (CVGBNM), is developed. Numerical applications and theoretical error estimates of the CVGBNM are derived for BIEs, potential problems and Stokes problems. Finally, numerical examples are given to demonstrate the efficacy of the method.

      PubDate: 2017-08-31T08:06:06Z
       
  • Efficient analysis of plates on nonlinear foundations
    • Abstract: Publication date: October 2017
      Source:Engineering Analysis with Boundary Elements, Volume 83
      Author(s): Ahmed Fady Farid, Marina Reda, Youssef F. Rashed
      This paper presents efficient analysis of plates on nonlinear foundations. The Reissner plate theory is used to model plates. Foundations are presented as the Winkler springs or the elastic half space. The developed analysis is mainly presented for tensionless foundation; however as demonstrated, it is straightforward extended to analysis of elastic-plastic foundations. The plate is analyzed using the boundary element method (BEM). Unlike the traditional BEM which uses equations in form ([H] {u} = [G] {t}), the presented formulation uses finite element like equations, in the form of ([K] {u} = {P}). An innovative formulation is presented to derive the relevant plate stiffness matrix [K] and load vector {P} from the BEM integral equation. Iterative procedures together with condensation process are used to eliminate degree of freedom at failed zones. Results of the present analysis are more accurate than those obtained from previously published results. The main advantages of the presented technique are its simplicity and accuracy and it gains both advantages of the boundary element and the finite element methods.

      PubDate: 2017-07-27T17:23:35Z
       
 
 
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