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  Subjects -> ENGINEERING (Total: 2258 journals)
    - CHEMICAL ENGINEERING (190 journals)
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    - ENGINEERING (1203 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 Microwaves, Antennas & Propagation     Hybrid Journal   (Followers: 11)
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: 14)
IETE Journal of Research     Open Access   (Followers: 8)
IETE Technical Review     Open Access   (Followers: 6)
IIE Transactions     Hybrid Journal   (Followers: 2)
Implementation Science     Open Access   (Followers: 12)
Indian Journal of Biotechnology (IJBT)     Open Access   (Followers: 2)
Industrial Data     Open Access   (Followers: 1)
Industrie et Technologies     Full-text available via subscription   (Followers: 17)
Informatik-Spektrum     Hybrid Journal   (Followers: 1)
Ingeniare : Revista Chilena de Ingenieria     Open Access  
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Ingenieria de Recursos Naturales y del Ambiente     Open Access  
Ingeniería e Investigación     Open Access  
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Ingenieria Industrial. Actualidad y Nuevas Tendencias     Open Access  
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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: 6)
Intelligent Control and Automation     Open Access   (Followers: 5)
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (Followers: 7)
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: 13)
International conference KNOWLEDGE-BASED ORGANIZATION     Open Access  
International Heat Treatment and Surface Engineering     Hybrid Journal   (Followers: 3)
International Journal for Numerical Methods in Engineering     Hybrid Journal   (Followers: 29)
International Journal for Numerical Methods in Fluids     Hybrid Journal   (Followers: 19)
International Journal for Simulation and Multidisciplinary Design Optimization     Open Access   (Followers: 2)
International Journal for the History of Engineering & Technology     Hybrid Journal   (Followers: 6)
International Journal of Abrasive Technology     Hybrid Journal   (Followers: 2)
International Journal of Adaptive Control and Signal Processing     Hybrid Journal   (Followers: 2)
International Journal of Adhesion and Adhesives     Hybrid Journal   (Followers: 16)
International Journal of Advancements in Technology     Open Access   (Followers: 1)
International Journal of Advances in Applied Sciences     Open Access   (Followers: 4)
International Journal of Advances in Engineering Sciences     Open Access   (Followers: 3)
International Journal of Advances in Engineering Sciences and Applied Mathematics     Hybrid Journal   (Followers: 1)
International Journal of Advances in Engineering, Science and Technology     Open Access   (Followers: 4)
International Journal of Aerodynamics     Hybrid Journal   (Followers: 14)
International Journal of Aerospace Innovations     Full-text available via subscription   (Followers: 16)
International Journal of Air-Conditioning and Refrigeration     Hybrid Journal   (Followers: 7)
International Journal of Antennas and Propagation     Open Access   (Followers: 8)
International Journal of Applied Ceramic Technology     Hybrid Journal   (Followers: 7)
International Journal of Applied Power Engineering     Open Access   (Followers: 4)
International Journal of Architectural Computing     Full-text available via subscription   (Followers: 4)
International Journal of Automation and Control Engineering     Open Access   (Followers: 2)
International Journal of Automotive Technology and Management     Hybrid Journal   (Followers: 5)
International Journal of Autonomic Computing     Hybrid Journal   (Followers: 1)
International Journal of Autonomous and Adaptive Communications Systems     Hybrid Journal   (Followers: 4)
International Journal of Basic and Applied Sciences     Open Access   (Followers: 4)
International Journal of Bifurcation and Chaos     Hybrid Journal   (Followers: 2)
International Journal of Biomedical and Clinical Engineering     Full-text available via subscription   (Followers: 3)
International Journal of Biomedical Imaging     Open Access   (Followers: 5)
International Journal of Cast Metals Research     Hybrid Journal  
International Journal of Circuit Theory and Applications     Hybrid Journal   (Followers: 2)
International Journal of Coal Science & Technology     Open Access   (Followers: 1)
International Journal of Collaborative Engineering     Hybrid Journal  
International Journal of Combinatorics     Open Access   (Followers: 1)
International Journal of Communication Systems     Hybrid Journal   (Followers: 2)
International Journal of Computer Aided Engineering and Technology     Hybrid Journal  
International Journal of Computer Applications in Technology     Hybrid Journal   (Followers: 3)
International Journal of Control Science and Engineering     Open Access   (Followers: 5)
International Journal of Control, Automation and Systems     Hybrid Journal   (Followers: 12)
International Journal of Corrosion     Open Access   (Followers: 10)
International Journal of Crashworthiness     Hybrid Journal   (Followers: 7)
International Journal of Design Engineering     Hybrid Journal   (Followers: 14)
International Journal of Digital Multimedia Broadcasting     Open Access   (Followers: 5)
International Journal of Education and Management Engineering     Open Access   (Followers: 2)
International Journal of Education Economics and Development     Hybrid Journal   (Followers: 3)
International Journal of Embedded Systems     Hybrid Journal   (Followers: 5)
International Journal of Emerging Multidisciplinary Fluid Sciences     Full-text available via subscription   (Followers: 1)
International Journal of Energy Optimization and Engineering     Hybrid Journal   (Followers: 3)
International Journal of Engine Research     Hybrid Journal   (Followers: 1)
International Journal of Engineering & Technology     Open Access   (Followers: 4)
International Journal of Engineering and Manufacturing     Open Access   (Followers: 1)
International Journal of Engineering Education     Full-text available via subscription   (Followers: 6)
International Journal of Engineering Management and Economics     Hybrid Journal   (Followers: 3)
International Journal of Engineering Mathematics     Open Access   (Followers: 2)
International Journal of Engineering Pedagogy     Open Access  
International Journal of Engineering Practical Research     Open Access  
International Journal of Engineering Research in Africa     Full-text available via subscription   (Followers: 1)
International Journal of Engineering Science     Hybrid Journal   (Followers: 6)
International Journal of Engineering Systems Modelling and Simulation     Hybrid Journal   (Followers: 8)
International Journal of Engineering, Science and Technology     Open Access  
International Journal of Engineering, Social Justice, and Peace     Open Access   (Followers: 5)
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: 35)
International Journal of Flow Control     Full-text available via subscription   (Followers: 4)
International Journal of Foresight and Innovation Policy     Hybrid Journal   (Followers: 7)
International Journal of Fracture     Hybrid Journal   (Followers: 11)
International Journal of Geo-Engineering     Open Access  
International Journal of Geotechnical Engineering     Hybrid Journal   (Followers: 5)
International Journal of Grid and Utility Computing     Hybrid Journal  
International Journal of Heat and Fluid Flow     Hybrid Journal   (Followers: 31)
International Journal of Heat and Mass Transfer     Hybrid Journal   (Followers: 131)
International Journal of Heavy Vehicle Systems     Hybrid Journal   (Followers: 6)
International Journal of Hypersonics     Full-text available via subscription   (Followers: 4)
International Journal of Imaging Systems and Technology     Hybrid Journal   (Followers: 1)
International Journal of Impact Engineering     Hybrid Journal   (Followers: 9)
International Journal of Information Acquisition     Hybrid Journal   (Followers: 1)
International Journal of Innovation and Applied Studies     Open Access   (Followers: 5)
International Journal of Innovation Science     Full-text available via subscription   (Followers: 9)
International Journal of Innovative Technology and Research     Open Access   (Followers: 1)
International Journal of Integrated Engineering     Open Access  
International Journal of Intelligent Engineering Informatics     Hybrid Journal  
International Journal of Intelligent Systems and Applications in Engineering     Open Access   (Followers: 2)
International Journal of Lifecycle Performance Engineering     Hybrid Journal   (Followers: 1)
International Journal of Machine Tools and Manufacture     Hybrid Journal   (Followers: 5)
International Journal of Manufacturing Research     Hybrid Journal   (Followers: 6)
International Journal of Manufacturing Technology and Management     Hybrid Journal   (Followers: 8)
International Journal of Materials and Product Technology     Hybrid Journal   (Followers: 4)
International Journal of Mathematical Education in Science and Technology     Hybrid Journal   (Followers: 8)
International Journal of Mathematics in Operational Research     Hybrid Journal  
International Journal of Medical Engineering and Informatics     Hybrid Journal   (Followers: 3)
International Journal of Micro Air Vehicles     Full-text available via subscription   (Followers: 7)
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 3)
International Journal of Microwave Science and Technology     Open Access   (Followers: 4)
International Journal of Mobile Network Design and Innovation     Hybrid Journal   (Followers: 1)
International Journal of Multiphase Flow     Hybrid Journal   (Followers: 4)
International Journal of Nanomanufacturing     Hybrid Journal  
International Journal of Nanoscience     Hybrid Journal   (Followers: 2)
International Journal of Nanotechnology     Hybrid Journal   (Followers: 5)
International Journal of Nanotechnology and Molecular Computation     Full-text available via subscription   (Followers: 2)
International Journal of Navigation and Observation     Open Access   (Followers: 18)
International Journal of Network Management     Hybrid Journal   (Followers: 1)
International Journal of Nonlinear Sciences and Numerical Simulation     Hybrid Journal  
International Journal of Numerical Methods for Heat & Fluid Flow     Hybrid Journal   (Followers: 9)
International Journal of Optics     Open Access   (Followers: 2)
International Journal of Organisational Design and Engineering     Hybrid Journal   (Followers: 6)
International Journal of Pattern Recognition and Artificial Intelligence     Hybrid Journal   (Followers: 6)
International Journal of Pavement Engineering     Hybrid Journal   (Followers: 4)
International Journal of Physical Modelling in Geotechnics     Hybrid Journal   (Followers: 4)
International Journal of Plasticity     Hybrid Journal   (Followers: 6)
International Journal of Plastics Technology     Hybrid Journal   (Followers: 1)
International Journal of Polymer Analysis and Characterization     Hybrid Journal   (Followers: 6)
International Journal of Polymer Science     Open Access   (Followers: 22)
International Journal of Precision Engineering and Manufacturing     Hybrid Journal   (Followers: 6)
International Journal of Precision Engineering and Manufacturing-Green Technology     Hybrid Journal  
International Journal of Precision Technology     Hybrid Journal  
International Journal of Pressure Vessels and Piping     Hybrid Journal   (Followers: 17)
International Journal of Production Economics     Hybrid Journal   (Followers: 13)
International Journal of Quality and Innovation     Hybrid Journal   (Followers: 5)
International Journal of Quality Assurance in Engineering and Technology Education     Full-text available via subscription   (Followers: 3)
International Journal of Quality Engineering and Technology     Hybrid Journal   (Followers: 2)
International Journal of Quantum Information     Hybrid Journal   (Followers: 2)
International Journal of Rapid Manufacturing     Hybrid Journal   (Followers: 4)
International Journal of Recent Contributions from Engineering, Science & IT     Open Access  
International Journal of Reliability, Quality and Safety Engineering     Hybrid Journal   (Followers: 11)
International Journal of Renewable Energy Technology     Hybrid Journal   (Followers: 9)
International Journal of Robust and Nonlinear Control     Hybrid Journal   (Followers: 4)
International Journal of Science Engineering and Advance Technology     Open Access  
International Journal of Sediment Research     Full-text available via subscription   (Followers: 3)
International Journal of Self-Propagating High-Temperature Synthesis     Hybrid Journal   (Followers: 2)
International Journal of Service Science, Management, Engineering, and Technology     Full-text available via subscription   (Followers: 1)
International Journal of Signal and Imaging Systems Engineering     Hybrid Journal  
International Journal of Six Sigma and Competitive Advantage     Hybrid Journal   (Followers: 2)
International Journal of Social Robotics     Hybrid Journal   (Followers: 2)
International Journal of Software Engineering and Knowledge Engineering     Hybrid Journal   (Followers: 3)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 4)
International Journal of Speech Technology     Hybrid Journal   (Followers: 7)
International Journal of Spray and Combustion Dynamics     Full-text available via subscription   (Followers: 12)
International Journal of Surface Engineering and Interdisciplinary Materials Science     Full-text available via subscription   (Followers: 1)
International Journal of Surface Science and Engineering     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Engineering     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Manufacturing     Hybrid Journal   (Followers: 5)
International Journal of Systems and Service-Oriented Engineering     Full-text available via subscription  
International Journal of Systems Assurance Engineering and Management     Hybrid Journal  
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 4)
International Journal of Technoethics     Full-text available via subscription   (Followers: 1)
International Journal of Technology Management and Sustainable Development     Hybrid Journal   (Followers: 1)
International Journal of Technology Policy and Law     Hybrid Journal   (Followers: 6)
International Journal of Telemedicine and Applications     Open Access   (Followers: 3)
International Journal of Thermal Sciences     Hybrid Journal   (Followers: 13)
International Journal of Thermodynamics     Open Access   (Followers: 8)
International Journal of Turbo & Jet-Engines     Hybrid Journal   (Followers: 3)
International Journal of Ultra Wideband Communications and Systems     Hybrid Journal  
International Journal of Vehicle Autonomous Systems     Hybrid Journal  
International Journal of Vehicle Design     Hybrid Journal   (Followers: 6)
International Journal of Vehicle Information and Communication Systems     Hybrid Journal   (Followers: 2)
International Journal of Vehicle Noise and Vibration     Hybrid Journal   (Followers: 4)
International Journal of Vehicle Safety     Hybrid Journal   (Followers: 6)
International Journal of Vehicular Technology     Open Access   (Followers: 4)
International Journal of Virtual Technology and Multimedia     Hybrid Journal   (Followers: 3)
International Journal of Wavelets, Multiresolution and Information Processing     Hybrid Journal   (Followers: 1)
International Journal on Artificial Intelligence Tools     Hybrid Journal   (Followers: 5)
International Nano Letters     Open Access   (Followers: 6)
International Review of Applied Sciences     Open Access  

  First | 1 2 3 4 5 6 7 | Last

Journal Cover Engineering Analysis with Boundary Elements
  [SJR: 1.216]   [H-I: 42]   [1 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0955-7997
   Published by Elsevier Homepage  [2969 journals]
  • Crack analysis by using the enriched singular boundary method
    • Abstract: Publication date: November 2016
      Source:Engineering Analysis with Boundary Elements, Volume 72
      Author(s): Ji Ma, Wen Chen, Ji Lin
      In this paper, we make the first attempt to extend the singular boundary method to crack problems in conjunction with the domain decomposition technique. In order to characterize singular behaviors around cracks, enriched functions are analytically derived from the governing equations and the corresponding conditions containing singularities. We verify the present enriched singular boundary method to the torsion problem of a cracked bar and the acoustic propagation problem in crack media, which are governed by Laplace and Helmholtz equations, respectively. Numerical results demonstrate the accuracy and efficiency of the proposed scheme.


      PubDate: 2016-08-21T13:11:53Z
       
  • More accurate results for nonlinear generalized
           Benjamin-Bona-Mahony-Burgers (GBBMB) problem through spectral meshless
           radial point interpolation (SMRPI)
    • Abstract: Publication date: November 2016
      Source:Engineering Analysis with Boundary Elements, Volume 72
      Author(s): Elyas Shivanian, Ahmad Jafarabadi
      In this article, the spectral meshless radial point interpolation (SMRPI) technique is applied to the nonlinear generalized Benjamin-Bona-Mahony-Burgers (GBBMB) in two-dimension with initial and Dirichlet-type boundary conditions. This method is based on erudite combination of meshless methods and spectral collocation techniques. The point interpolation method with the help of radial basis functions is used to construct shape functions which play as basis functions in the frame of SMRPI. To treat the nonlinearity part, a kind of predictor-corrector scheme combined with Crank-Nicolson technique is adopted. We prove that the time discrete scheme is stable respect to the time variable in H 1 and convergent with convergence order O ( δ t ) . To show the high accuracy of SMRPI, a comparison study of the present method and recently applied interpolating element-free Galerkin technique is given through applying on GBBMB equation. The results reveal that the method is more accurate and possesses low complexity.


      PubDate: 2016-08-21T13:11:53Z
       
  • Analysis of underwater acoustic scattering problems using stable
           node-based smoothed finite element method
    • Abstract: Publication date: November 2016
      Source:Engineering Analysis with Boundary Elements, Volume 72
      Author(s): Yingbin Chai, Wei Li, Tianyun Li, Zhixiong Gong, Xiangyu You
      A stable node-based smoothed finite element method (SNS-FEM) is presented that cures the “overly-soft” property of the original node-based smoothed finite element method for the analysis of underwater acoustic scattering problems. In the SNS-FEM model, the node-based smoothed gradient field is enhanced by additional stabilization term related to the gradient variance items. It is demonstrated that SNS-FEM provides an ideal stiffness of the continuous system and improves the performance of the NS-FEM and FEM. In order to handle the acoustic scattering problems in unbounded domain, the well known Dirichlet-to-Neumann (DtN) boundary condition is combined with the present SNS-FEM to give a SNS-FEM-DtN model for exterior acoustic problems. Several numerical examples are investigated and the results show that the SNS-FEM-DtN model can achieve more accurate solutions compared to the NS-FEM and FEM.


      PubDate: 2016-08-17T18:03:24Z
       
  • Crack propagation in non-homogenous materials: Evaluation of mixed-mode
           SIFs, T-stress and kinking angle using a variant of EFG Method
    • Abstract: Publication date: November 2016
      Source:Engineering Analysis with Boundary Elements, Volume 72
      Author(s): N. Muthu, S.K. Maiti, B.G. Falzon, Wenyi Yan
      A new variant of the Element-Free Galerkin (EFG) method, that combines the diffraction method, to characterize the crack tip solution, and the Heaviside enrichment function for representing discontinuity due to a crack, has been used to model crack propagation through non-homogenous materials. In the case of interface crack propagation, the kink angle is predicted by applying the maximum tangential principal stress (MTPS) criterion in conjunction with consideration of the energy release rate (ERR). The MTPS criterion is applied to the crack tip stress field described by both the stress intensity factor (SIF) and the T-stress, which are extracted using the interaction integral method. The proposed EFG method has been developed and applied for 2D case studies involving a crack in an orthotropic material, crack along an interface and a crack terminating at a bi-material interface, under mechanical or thermal loading; this is done to demonstrate the advantages and efficiency of the proposed methodology. The computed SIFs, T-stress and the predicted interface crack kink angles are compared with existing results in the literature and are found to be in good agreement. An example of crack growth through a particle-reinforced composite materials, which may involve crack meandering around the particle, is reported.


      PubDate: 2016-08-12T17:41:09Z
       
  • A direct velocity-pressure coupling Meshless algorithm for incompressible
           fluid flow simulations
    • Abstract: Publication date: November 2016
      Source:Engineering Analysis with Boundary Elements, Volume 72
      Author(s): Andrés Vidal, Alain J. Kassab, Eduardo A. Divo
      A localized radial-basis function (RBF) Meshless algorithm, with a direct velocity-pressure coupling scheme, is presented for fluid flow simulations. The proposed method is a combination of several efficient techniques found in different Computational Fluid Dynamic (CFD) procedures and has very low numerical diffusion. The fundamental idea of this method lays on several important inconsistencies found in three of the most popular techniques used in CFD, segregated procedures, streamline-vorticity formulation for 2D viscous flows, and the fractional-step method, very popular in Direct Numerical Simulation (DNS) and Large-Eddy Simulation (LES). The proposed scheme uses the classical segregated point distribution for all primitive variables, and performs all necessary interpolations with the accurate RBF technique. The viscous term is estimated using standard second order finite differences, while the convection term is discretized using the low-diffusion flux limiters. The velocity-pressure coupling is performed with the flow equations in their original form, and using a direct velocity-pressure coupling scheme. This way of solving the flow equations has no approximations in the boundary conditions. The method is validated with the 2D lid-driven cavity problem and very good agreement is found with classical data.


      PubDate: 2016-08-12T17:41:09Z
       
  • Sub-regions without subdomain partition with boundary elements
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Carlos Friedrich Loeffler, Webe João Mansur
      This paper presents a simple and effective numerical procedure to model domains with sectorial heterogeneous properties using the boundary element method. The physical problem is divided into a complete homogenous domain and other non homogeneous sectors. Matrices similar to the standard H boundary element matrix are constructed for each sector, which are related to the energy stored in them. The assembly of the coefficients related to the sectorial matrices in the final boundary element system is done through the direct introduction of unknown variables at internal auxiliary points. Comparatively to the sub-regions technique, the proposed procedure is advantageous, since the effect of interface approximations is attenuated and computer implementation of its corresponding numerical model is simpler.


      PubDate: 2016-08-08T17:26:11Z
       
  • Single layer regularized meshless method for three dimensional Laplace
           problem
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Lin Liu, Hong Zhang
      The subtraction and adding-back technique for Regularized Meshless Method (RMM) has been proposed by Young et al. (2005) [8] on 2-D Laplace problem and extended to 3-D Laplace problem by Young et al. (2009) [13], where the kernel functions of double layer potentials were adopted to desingularize fundamental solution singularity while the source points are overlapped on the physical points. Here the Single Layer Regularized Meshless Method (SRMM) is proposed. The solutions are represented by single layer potential. The singularity of the fundamental solution is desingularized by the carefully chosen particular solution in the null-fields of the boundary integral equation using the subtraction and adding-back technique for the Dirichlet boundary condition. The double layer potential is adopted for the Neumann boundary condition. The numerical examples show that the convergence trend and accuracy of the SRMM are better than those of using other methods (RMM, IBDS) by one or two orders of magnitude.


      PubDate: 2016-08-08T17:26:11Z
       
  • Interior field methods for Neumann problems of Laplace's equation in
           elliptic domains, comparisons with degenerate scales
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Zi-Cai Li, Li-Ping Zhang, Ming-Gong Lee
      The interior field method (IFM) is applied to Neumann problems for Laplace's equation in elliptic domains. The polynomial convergence rates are derived, and small condition number as O(N) can be obtained, where N is the number of particular solutions used. Moreover, the effective condition number as O ( 1 ) is explored, to display excellent stability (Li et al., 2015 [21]). Numerical experiments are carried out, to support the analysis made. The error analysis of the IFM for Dirichlet problems in circular domains is reported in Li et al. (2016) [19]. The error and stability analysis of the IFM for Neumann problems in elliptic domains is more advanced and challenging; this is the first goal of this paper. The second goal is to compare the Neumann problems with the degenerate scales of Dirichlet problems; some useful guidances are found for application. From the comparisons, the conservation law is essential to guarantee the unique solutions. The adaptive processes are also proposed to deal with the algorithm singularity of Dirichlet problems; they may be applied to the boundary element method (BEM), the original NFM, and the indirect BIEM for the arbitrary smooth boundary or the convex polygonal boundary.


      PubDate: 2016-08-08T17:26:11Z
       
  • Simulation of micro-seismicity in response to injection/production in
           large-scale fracture networks using the fast multipole displacement
           discontinuity method (FMDDM)
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Moien Farmahini-Farahani, Ahmad Ghassemi
      Analysis of fluid flow, permeability, and micro-seismicity in large fracture networks are essential for economical production from engineered geothermal and petroleum reservoirs. In this work, the fluid pressure change, as a result of injection and production inside a stochastic, deformable, non-propagating fracture network is modeled using the fast multipole displacement discontinuity method combined with the finite difference method. The former is employed to simulate the response of the fracture network to changes in the pressure due to fluid injection. In addition to pressure changes inside the fracture network, changes in fracture status with respect to normal (“joint” versus hydraulic fracture) and shear (stick versus slip) deformation, dilation, and friction coefficient are considered. Rate-and-state friction model and the Mohr-Coulomb criterion are used to model slip and potential micro-earthquakes and their seismic moments. Simulation results show that increase in pressure inside a fracture network leads to permanent slip and nucleation of micro-earthquakes which are mostly influenced by the orientation of the fractures and the magnitude of fluid pressure and the injection rate. Injecting the same volume of water over a longer time period decreases the number and magnitude of seismic events.


      PubDate: 2016-08-08T17:26:11Z
       
  • Shape reconstructions from phaseless data
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Kuo-Ming Lee
      For the inverse scattering problem from a sound-soft obstacle with full far field data, a simple hybrid method was proposed by Lee [9]. In this research, we consider the case where as data only the modulus of the far field are available. The aim is to reconstruct the shape of the obstacle with this limited data.


      PubDate: 2016-08-08T17:26:11Z
       
  • MHD natural convection in a semi-annulus enclosure filled with water-based
           nanofluid using DRBEM
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): F.S. Oğlakkaya, Canan Bozkaya
      Natural convection of a water-based nanofluid consisting Cu nanoparticles in a semi-annulus enclosure subjected to a magnetic field is considered. The inner wall has constant heat flux, the outer wall is maintained at a cold temperature and the other two walls are thermally insulated. The governing equations derived by considering the effect of magnetic field are solved numerically using the dual reciprocity boundary method (DRBEM) with constant elements. The boundary only nature of the dual reciprocity method results in considerably small computational cost in obtaining the solution. The simulations focus on the effects of the Rayleigh number, the Hartmann number, the nanoparticle volume fraction, and the inclination angles of the enclosure and the magnetic field on the flow and heat transfer characteristics. The results show that the convection and the average Nusselt number ( Nu ¯ ) decrease with an increase in the strength of the magnetic field whereas they increase by increasing the Rayleigh number. Furthermore, an increase in Hartmann number accelerates the rate of decrease in Nu ¯ as inclination angles decrease. Thus, the inclined magnetic field and the inclination angle of the enclosure can be used as control parameters for enhancing the heat transfer convection and flow behavior in an enclosure.


      PubDate: 2016-08-04T17:14:00Z
       
  • Applications of the Clifford algebra valued boundary element method to
           electromagnetic scattering problems
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Jia-Wei Lee, Li-Wei Liu, Hong-Ki Hong, Jeng-Tzong Chen
      Electromagnetic problems governed by Maxwell's equations are solved by using a Clifford algebra valued boundary element method (BEM). The well-known Maxwell's equations consist of eight pieces of scalar partial differential equations of the first order. They can be rewritten in terms of the language of Clifford analysis as a nonhomogeneous k-Dirac equation with a Clifford algebra valued function. It includes three-component electric fields and three-component magnetic fields. Furthermore, we derive Clifford algebra valued boundary integral equations (BIEs) with Cauchy-type kernels and then develop a Clifford algebra valued BEM to solve electromagnetic scattering problems. To deal with the problem of the Cauchy principal value, we use a simple Clifford algebra valued k-monogenic function to exactly evaluate the Cauchy principal value. Free of calculating the solid angle for the boundary point is gained. The remaining boundary integral is easily calculated by using a numerical quadrature except the part of Cauchy principal value. This idea can also preserve the flexibility of numerical method, hence it is suitable for any geometry shape. In the numerical implementation, we introduce an oriented surface element instead of the unit outward normal vector and the ordinary surface element. In addition, we adopt the Dirac matrices to express the bases of Clifford algebra C l 3 ( ℂ ) . We also use an orthogonal matrix to transform global boundary densities into local boundary densities for satisfying boundary condition straightforward. Finally, two electromagnetic scattering problems with a perfect spherical conductor and a prolate spheroidal conductor are both considered to examine the validity of the Clifford algebra valued BEM with Cauchy-type kernels.


      PubDate: 2016-08-04T17:14:00Z
       
  • Numerical and experimental investigation on vibro-acoustic response of a
           shaft-hull system
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Chenyang Li, Jian Wang, Yegao Qu, Zhiyi Zhang, Hongxing Hua
      The vibro-acoustic characteristics of a submerged shaft-hull system are investigated by numerical and experimental methods. A numerical model for the structure-fluid interaction of the system is formulated by the coupled finite element/boundary element methods. With this model, the influence of the shaft vibration on the dynamic and acoustic responses of the submerged shaft-hull system is analyzed via the modal decomposition technology. It is found that reduction of the stiffness of the stern bearing and symmetrization of the foundation can reduce the sound radiation from the submerged shaft-hull system subjected to transversal and axial force excitations, respectively. The numerical solutions are validated by the experimental results, and reasonable agreement is observed.


      PubDate: 2016-08-04T17:14:00Z
       
  • A coupled FE-BIE model for the static analysis of Timoshenko beams bonded
           to an orthotropic elastic half-plane
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Enrico Tezzon, Nerio Tullini, Luca Lanzoni
      Interface displacements, surface tractions and stresses of a flexible beam bonded to an elastic orthotropic half-plane are analysed by means of a Finite Element-Boundary Integral Equation (FE-BIE) method. Numerical results are obtained by using locking-free shear deformable beams and piecewise constant interfacial reactions. Making use of the generalised Green's function for the half-plane, the mechanical behaviour of fully bonded or detached beams subjected to force, couple or thermal load is investigated. The special cases of a beam in bilateral frictionless contact with the half-plane and a beam having a vanishing bending rigidity (thin film) are considered also. In particular, the maximum bending moment of beams subjected to a vertical point force are compared with some closed-form solutions of the contact problem of a rigid indenter and with the solution of an infinite Euler–Bernoulli beam in bilateral frictionless contact with an isotropic substrate.


      PubDate: 2016-08-04T17:14:00Z
       
  • Editorial Board
    • Abstract: Publication date: September 2016
      Source:Engineering Analysis with Boundary Elements, Volume 70




      PubDate: 2016-07-29T16:38:12Z
       
  • An ACA-SBM for some 2D steady-state heat conduction problems
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Xing Wei, Bin Chen, Shenshen Chen, Shuohui Yin
      In this paper, an accelerated singular boundary method (SBM) incorporating adaptive cross approximation (ACA) is developed for the steady-state heat conduction problems. The SBM, a recently developed boundary collocation method, employs the fundamental solutions of the governing operators as the kernel functions, and desingularizes the source singularity with a concept of origin intensity factor. However, the SBM suffers fully-populated influence matrix which results in prohibitively expensive operation counts and memory requirements as the number of degrees of freedom increases. In this paper, the ACA is applied to accelerate the SBM meanwhile reducing the memory requirement. Furthermore, the ACA-SBM is robust to different fundamental solutions, which enables it to deal with different heat conduction problems. The effectiveness, feasibility and robustness of the proposed method are numerically tested on different heat conduction problems including isotropic homogeneous, anisotropic homogeneous and non-homogeneous media with quadratic material variation of thermal conductivity, highlighting the accuracy as well as the significant reduction in memory storage and analysis time in comparison with the traditional SBM.


      PubDate: 2016-07-29T16:38:12Z
       
  • Coupling of BEM subdomains – BETI applied to collocation BEM with
           mixed basis functions
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Bernhard Lindner, Christian Duenser, Gernot Beer
      This work is about the coupling of subdomains for elasticity problems using the boundary element tearing and interconnecting method (BETI). BETI is a substructuring technique which is able to solve large problems involving subdomains efficiently, because its formulation is ideally suited for parallel computation. In contrast to the original formulation of BETI, where the symmetric Galerkin boundary element method (SGBEM) is applied, here the traditional collocation BEM is used. As will be shown the solution algorithm is applied in a very similar way as in the original version. Special attention will be paid to the distribution of tractions along interfaces of BEM subdomains. Especially if the coupling interface is not smooth but has corners and edges erroneous traction results can be obtained by using the non-symmetric approximation of the Dirichlet-to-Neumann map. For a sequential calculation involving several load steps this leads to unacceptable results if a classical continuous approximation of the physical fields is used. Therefore discontinuous basis functions for the displacement and traction field are introduced. As will be shown in this work the quality of results can be improved drastically by this technique.


      PubDate: 2016-07-29T16:38:12Z
       
  • Displacement and equilibrium mesh-free formulation based on integrated
           radial basis functions for dual yield design
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Phuc L.H. Ho, Canh V. Le, T. Tran-Cong
      This paper presents displacement and equilibrium mesh-free formulation based on integrated radial basis functions (iRBF) for upper and lower bound yield design problems. In these approaches, displacement and stress fields are approximated by the integrated radial basis functions, and the equilibrium equations and boundary conditions are imposed directly at the collocation points. In this paper it has been shown that direct nodal integration of the iRBF approximation can prevent volumetric locking in the kinematic formulation, and instability problems can also be avoided. Moreover, with the use of the collocation method in the static problem, equilibrium equations and yield conditions only need to be enforced at the nodes, leading to the reduction in computational cost. The mean value of the approximated upper and lower bound is found to be in excellent agreement with the available analytical solution, and can be considered as the actual collapse load multiplier for most practical engineering problems, for which exact solution is unknown.


      PubDate: 2016-07-29T16:38:12Z
       
  • Local Eshelby matrix in eigen-variable boundary integral equations for
           solids with particles and cracks in full space
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Yingjie Tang, Hang Ma, Cheng Yan
      In order for the large scale numerical simulation of solids with particles and cracks, the concept of local Eshelby matrix has been introduced into the computational model of the eigen-variable boundary integral equation (BIE) to resolve the problem of interactions among particles and cracks by joining the two concepts of the eigenstrain and eigen COD. The local Eshelby matrix in the present paper is considered as an extension of the concept of Eshelby tensor in numerical form for both equivalent inclusions and cracks, defined on the group of near field particles and cracks in full space. Through some typical numerical examples, the computations of stress intensity factors (SIF) are carried out and compared with the results of the sub-domain method using the dual BIE. With the proposed computational model, it is verified not only the correctness and feasibility but also the high efficiency of the present solution procedure, showing the potential of the proposed method for large scale numerical simulation of solids with particles and cracks.


      PubDate: 2016-07-29T16:38:12Z
       
  • Improved hybrid boundary solution for shell elements
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Taha H.A. Naga, Youssef F. Rashed
      In this paper, a new finite element for shell structures is developed using an improved hybrid boundary solution. First the variational boundary integral equation for shear-deformable plate bending problems is developed based on quadratic boundary elements. Hence such a formulation is coupled to a similar formulation for 2D plane stress problems to produce the developed shell elements. Numerical examples are presented to demonstrate the accuracy and validity of the proposed formulation.


      PubDate: 2016-07-29T16:38:12Z
       
  • Three-dimensional thermo-elastoplastic analysis of thick functionally
           graded plates using the meshless local Petrov–Galerkin method
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): R. Vaghefi, M.R. Hematiyan, A. Nayebi
      A numerical method based on the meshless local Petrov–Galerkin (MLPG) method is presented for three-dimensional (3D) thermo-elastoplastic analysis of thick functionally graded (FG) plates subjected to combined thermal and mechanical loads. The FG plate is assumed to be made of two constituents, whose volume fractions vary continuously in the thickness direction according to a power law. All material properties are considered to be temperature dependent. The von-Mises yield criterion and isotropic strain hardening rule are employed to describe the elastoplastic behaviors of the FG plates. The weak form is derived using the 3D equilibrium equations, and then it is transformed into local integral equations on brick-shaped local sub-domains by using a Heaviside step function as the test function. The proposed approach makes it possible to distribute more nodes in the direction of the material variation to construct the shape and test functions. Consequently, more accurate solutions can be obtained easily and effectively. Several numerical examples for temperature, displacement and stress analysis of thick FG plates are presented for different material gradients and boundary conditions. The obtained results have been compared with accurate finite element results and an excellent agreement has been observed.


      PubDate: 2016-07-25T16:22:05Z
       
  • Radial basis function-based pseudospectral method for static analysis of
           thin plates
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Artur Krowiak
      The paper deals with the implementation of radial basis function-based pseudospectral method (RBF-PS), which is a meshless numerical technique, to static analysis of thin, isotropic plates. The analyzed problem possesses multiple boundary conditions, therefore direct application of the RBF-PS is not straightforward. In the paper, some approaches to implement the method in such the case are presented. They are examined by the analysis of square plates as well as irregular shaped ones with various combinations of boundary conditions. A careful attention is paid to the problem of choosing an appropriate value of the shape parameter for radial basis functions and an effective approach is explained. The obtained results show the usefulness and high accuracy of the approaches proposed, confirming the advantages of the use of the radial basis function approximation in pseudospectral mode.


      PubDate: 2016-07-25T16:22:05Z
       
  • Implementation of CPCT based BIEs for 3D elasticity and its application in
           fracture mechanics
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Jia-He Lv, Xia-Ting Feng, Fei Yan, Bing-Rui Chen
      The accurate evaluation of singular boundary integrals is a long-debated issue for the successful implementation of BIEs. In the past decades, various methods have been developed, among which the singularity subtraction technique (SST) has been proved to be a unified method for various orders of singularities. However, the accuracy of original SST is sensitive to element shape due to the near singularity caused by element shape distortion. In this paper, a new conformal polar coordinate transformation (CPCT) for quadrilateral elements is proposed to eliminate the shape effect. Besides, an improved sigmoidal transformation is introduced in the angular direction to assign Gauss points more reasonably. By combination of the two strategies with original SST, a more efficient and robust numerical integration scheme for singular integrals can be obtained. Several numerical examples including crack problems are presented to demonstrate the accuracy and feasibility to coarse meshes for CPCT based BIEs and dual BEM.


      PubDate: 2016-07-18T15:46:47Z
       
  • Solid analysis of micron-sized thin structures with BEM for steady-state
           heat conduction
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Jia-He Lv, Xia-Ting Feng, Shao-Jun Li, Quan Jiang, Hao-Sen Guo
      Accurate thermal or mechanical analysis of thin structures has been a challenging task for various numerical methods, due to the exceeding closeness of the two neighboring surfaces. In this paper, the micron-sized interior-like thin structures for steady-state heat conduction is investigated with BEM. Three major difficulties would be encountered during solid analysis of thin structures with BEM: 1) degeneracy of the linear systems of equations; 2) evaluation of singular integrals over distorted elements; 3) evaluation of various orders of nearly singular integrals. To investigate the effect of singular and nearly singular integrals independently, the singularity subtraction technique (SST) and nonlinear distance transformation combined with adaptive subdivision method are employed to deal with singular and nearly singular integrals, respectively. Besides, a conformal mapping procedure aligned with sigmoidal transformation in angular direction is proposed to eliminate the near singularity derived from the distortion of element shape. Several challenging numerical examples with characteristic thickness h = 10 − 3 , including annular disk, hollow sphere and hollow torus examples, are solved with coarse meshes compared to original methods, and some meaningful conclusions have been obtained.


      PubDate: 2016-07-18T15:46:47Z
       
  • An improved exponential transformation for accurate evaluation of nearly
           singular boundary integrals in 3D BEM
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): Qing-Nian Yang, Yu Miao
      Accurate evaluation of nearly singular integrals is an important issue for the successful implementation of the boundary element method (BEM), and the exponential transformation has been proved to be feasible in dealing with nearly weak and strong singular integrals for 2D and 3D boundary elements with regular shape. In this paper, in order to eliminate the shape effect from distorted elements, an improved exponential transformation is proposed by combination of the conformal mapping and sigmoidal transformation in angular direction. Besides, the nearly hyper-singular integrals have been solved readily with a simple geometrical manipulation to convert them into line integrals. The performance of the conformal mapping based exponential transformation, including sensitivity to the relative distance, location of projection point and number of Gauss points used, is tested in detail through a distorted curved element extracted from cylinder surface. Finally, an alternative form of exponential transformation and comparisons with the distance transformation are discussed.


      PubDate: 2016-07-18T15:46:47Z
       
  • A boundary integral equation over the thin rotating blade of a wind
           turbine
    • Abstract: Publication date: October 2016
      Source:Engineering Analysis with Boundary Elements, Volume 71
      Author(s): K. Mescheryakov, M.A. Sumbatyan, A.A. Bondarchuk
      In the present paper we study the aerodynamics of a thin rotating Wind Turbine (WT) blade. Under the assumption of high specific speed (i.e. large angular velocity), by using the classical potential theory, the problem is reduced to a dual integral equation over the surface of the blade. Since a certain value of the axial component of the velocity vector, which is not known a priori, is present in the right-hand side of the basic dual integral equation, the method proposed is based on an iteration scheme. This rapidly converges in two-three steps. The method is tested on example of a small WT, by a comparison with the results obtained by the ANSYS-CFX finite-volume software.


      PubDate: 2016-07-18T15:46:47Z
       
  • Unsteady hydrodynamic interaction between two cylindroids in shallow water
           based on high-order panel method
    • Abstract: Publication date: September 2016
      Source:Engineering Analysis with Boundary Elements, Volume 70
      Author(s): Huafu Xu, Zaojian Zou, Lu Zou, Xiaoyan Liu
      A NURBS-based high-order panel method is developed for predicting the hydrodynamic interaction of two bodies moving along parallel courses in shallow water. Source and dipole are distributed on the body surfaces, while dipole is distributed on the wake surfaces; the singularity strengths are determined by satisfying the boundary condition on the body surfaces and the Kutta condition at the trailing edges. The wave-making effect is neglected under the low speed assumption; the image method is used to deal with the effects of finite water depth and undisturbed free surface. The time-stepping method is used to update the velocity potential and the position of each body. Firstly, calculations are carried out for a cylindroid passing a stationary cylindroid and two cylindroids moving in the same direction with the same speed. Detailed convergence study with respect to panel size, time step and truncated mirrored images is carried out. On the basis of convergence study, numerical results are compared with experimental measurements to validate the numerical method. Then, calculations are conducted for two cylindroids during passing, meeting and overtaking under different lateral distances between cylindroids, different water depths and different cylindroid geometry. Numerical results are presented to demonstrate the effects of these factors.


      PubDate: 2016-07-14T15:31:38Z
       
  • Numerical solution for the degenerate scale in 2D Laplace equation for
           notch in half-plane using null field BIE
    • Abstract: Publication date: September 2016
      Source:Engineering Analysis with Boundary Elements, Volume 70
      Author(s): Y.Z. Chen
      This paper provides a numerical solution for the degenerate scale in the antiplane elasticity with the traction free condition along the half-plane boundary. The image method is used in the formulation of the fundamental solution. After using the Betti׳s reciprocal theorem between the fundamental field and the physical field, the null field boundary integral equation (BIE) is obtained. After performing the coordinate transform, the BIE can be alternatively formulated in the normal scale, and a linear algebraic equation is obtained after discretization. The influence matrix in the normal scale is invertible. The degenerate scale can be evaluated by the invertible property of the influence matrix.


      PubDate: 2016-07-06T14:18:42Z
       
  • Average source boundary node method for potential problems
    • Abstract: Publication date: September 2016
      Source:Engineering Analysis with Boundary Elements, Volume 70
      Author(s): Yao-Ming Zhang, Fang-Ling Sun, Der-Liang Young, Wen Chen, Yan Gu
      A new boundary meshfree method, named the average source boundary node method (ASBNM), is presented in this paper for potential problems. The method is based on coupling a ‘completely’ regularized boundary integral equation (CRBIE) with direct unknowns developed in this paper, removing the singularity computation, and an average source technique (AST). In this approach there are two critical developments. One is the presentation of a new removal singularity technique that results in the CRBIE, and therefore all diagonal coefficients of influence matrices can be determined analytically by the off-diagonal ones, unlike some existing boundary meshless approaches that determine diagonal coefficients from the fundamental solution by applying a known solution inside the domain, which amounts to solve the problem twice. The other is the introduction of an AST, by which the distributed source on a segment/cell can be reduced to a concentrated point source and therefore the boundary integrals in the CRBIE are not necessary. Hence, in the ASBNM only boundary nodes are required for computation without using any element or integration concept. Several test examples are presented to demonstrate the effectiveness and robustness of the proposed ASBNM.


      PubDate: 2016-07-02T13:18:39Z
       
  • A boundary element and level set based topology optimisation using
           sensitivity analysis
    • Abstract: Publication date: September 2016
      Source:Engineering Analysis with Boundary Elements, Volume 70
      Author(s): B. Ullah, J. Trevelyan
      The structural topology optimisation method presented in this paper is based on the boundary element method, level set method and shape sensitivity analysis for two-dimensional linear elastic problems. The proposed method automatically nucleates holes within the design domain during the optimisation process using a topological derivative based hole insertion criterion. The level set method is used to provide an implicit description of the structural geometry, which is capable of automatically handling topological changes, i.e. holes merging with each other or with the boundary. During the optimisation process non-uniform rational b-splines are fitted through the zero level set contours, which links an implicit geometry representation to its structural model. In addition, this provides an optimal design in standard CAD format, and without intermediate material densities, which can be directly used in other design processes. The proposed optimisation method is tested against different benchmark examples and the optimal geometries generated are in close agreement those available in the literature of topology optimisation.


      PubDate: 2016-06-27T12:08:15Z
       
  • An efficient nodal integration with quadratic exactness for
           three-dimensional meshfree Galerkin methods
    • Abstract: Publication date: September 2016
      Source:Engineering Analysis with Boundary Elements, Volume 70
      Author(s): Bingbing Wang, Qinglin Duan, Yulong Shao, Xikui Li, Dixiong Yang, Hongwu Zhang
      Quadratically consistent nodal integration (QCNI) for three-dimensional meshfree Galerkin methods with second order approximation is presented. The number of integration points is dramatically reduced since the weak form is evaluated only at approximation nodes. The stabilization for such reduced integration stems from the correction of nodal derivatives. Such correction is based on the orthogonality condition between the stress and strain difference in the framework of Hu-Washizu three-field variational principle. Taylor series expansion is employed such that a linear strain field in each background integration cell can be exactly reproduced. Three-dimensional quadratic patch test is exactly passed by QCNI and thus it possesses quadratic exactness. In contrast, the stabilized conforming nodal integration (SCNI) which is so far the most successful nodal integration technique can only reproduce a constant strain field in each integration cell and fails to pass the quadratic patch test. The comprehensive superiorities of the proposed QCNI over the existing SCNI in accuracy, convergence, efficiency and smoothness of the resulting stress fields are further demonstrated by several three-dimensional numerical examples. Especially, it is shown in some example that the accuracy of QCNI is surprisingly four order higher than that of SCNI.


      PubDate: 2016-06-27T12:08:15Z
       
  • A new meshless method for solving steady-state nonlinear heat conduction
           problems in arbitrary plane domain
    • Abstract: Publication date: September 2016
      Source:Engineering Analysis with Boundary Elements, Volume 70
      Author(s): Chih-Wen Chang
      For solving steady-state nonlinear heat conduction problems (HCPs) in arbitrary plane domain enclosed by a complex boundary shape, the meshless methods are convenient to programming, of which the polynomial expansion method seems the simplest one. However, it is seldom used as a major medium to solve nonlinear partial differential equations owing to its highly ill-conditioned behavior. First, we decompose the steady-state nonlinear heat conduction equation into a linear portion on the left-hand side, and leave other terms on the right-hand side as a non-homogeneous portion. Then, we need to solve a steady-state linear heat conduction problem in each iteration, for which we propose a multiple-scale Pascal triangle method to generate the linear algebraic equations, where the multiple scales are automatically decided by the collocation points. We can find that these scales can largely reduce the condition number of the coefficient matrix in each linear system, such that the iteration process is convergent very quickly, and the numerical solutions obtained are very accurate and stable against very large noise to over 50%, no matter for the Dirichlet and mixed-type boundary value problems. Numerical results confirm the validity of the present multiple-scale polynomial expansion method for solving steady-state nonlinear HCPs in arbitrary plane domains.


      PubDate: 2016-06-18T18:36:15Z
       
  • 3-D rolling processing analysis by Fast Multipole Boundary Element Method
    • Abstract: Publication date: September 2016
      Source:Engineering Analysis with Boundary Elements, Volume 70
      Author(s): Chunxiao Yu, Deyi Liu, Yongjiang Zheng, Guangxian Shen
      This paper presents the numerical analysis of 3-D rolling processing by a kind of Fast Multipole Boundary Element Method (FM-BEM). The FM-BEM combines the Fast Multipole Method (FMM) and Boundary Element Method (BEM), for which the fundamental formulations and numerical implementations are obtained. Then a node-to-surface frictional contact model is provided and contact constraints are linearized. For the solution system, an improved Generalized Minimal Residual Algorithm (GMRES) is employed as a fast solver. Combined with high performance computing, a cold rolling process of 2030 four-high mill with a width-to-thickness ratio of 1850 is successfully simulated, and comprehensive new rolling information is obtained. Numerical results show that the presented FM-BEM requires less artificial assumptions, and it has higher precision and efficiency as compared to the traditional BEM, Finite Element Method (FEM) and Finite Difference Method (FDM). It is a breakthrough progress in the simulation of rolling engineering, which is of great significance.


      PubDate: 2016-06-18T18:36:15Z
       
  • Stochastic analysis using the generalized perturbation stable node-based
           smoothed finite element method
    • Abstract: Publication date: September 2016
      Source:Engineering Analysis with Boundary Elements, Volume 70
      Author(s): X.B. Hu, X.Y. Cui, H. Feng, G.Y. Li
      The traditional stochastic finite element method based on the finite element method fails to give the fine solution in precise determination of reliable problems when the computer power consumption is limited. To cure this fatal defect, the generalized nth order stochastic perturbation technique based on a stable node-based smoothed finite element method (GS_SNS-FEM) is presented. The framework intends to essentially improve the accuracy, lower the mesh limitation and occupy much less computational consumption for stochastic problems, especially when its second order realization is ineffective for large variations of input random fields. Besides, the nth orders expansion makes it possible to get the prefect accuracy for expected values and variances. Numerical examples including the static and dynamic problems are completed and compared with the solution of Monte Carlo simulation. It is found that the SNS-FEM applied in the stochastic problem can improve the accuracy of static and dynamic results, largely decrease the time cost, and lower the requirement of mesh.


      PubDate: 2016-06-18T18:36:15Z
       
  • Editorial Board
    • Abstract: Publication date: July 2016
      Source:Engineering Analysis with Boundary Elements, Volume 68




      PubDate: 2016-06-15T05:42:03Z
       
  • Interactions of fully nonlinear solitary wave with a freely floating
           vertical cylinder
    • Abstract: Publication date: August 2016
      Source:Engineering Analysis with Boundary Elements, Volume 69
      Author(s): B.Z. Zhou, G.X. Wu, Q.C. Meng
      Fully nonlinear numerical interaction of a transient wave with a three dimensional structure has been analysed based on a higher-order boundary element method (BEM). The BEM mesh on the free surface is generated through a combination of the structured and unstructured meshes. Through some auxiliary functions, the mutual dependence of fluid/structure motions is decoupled, which allows the body acceleration to be obtained without the knowledge of the pressure distribution. The solitary wave is used as the case study for the transient wave. It is obtained by the third order theory and the fully nonlinear theory. The accuracy of the present numerical model is verified through the steady propagation of a solitary wave and comparison with the published results for solitary wave interaction with a vertical wall. Simulations are then made to study solitary wave interaction with a truncated cylinder. Numerical results are provided for motions, forces and run-ups on the cylinder and comparison between results for the fixed cylinder and the freely floating cylinder is also made.


      PubDate: 2016-06-15T05:42:03Z
       
  • Meshfree approach for linear and nonlinear analysis of sandwich plates: A
           critical review of twenty plate theories
    • Abstract: Publication date: August 2016
      Source:Engineering Analysis with Boundary Elements, Volume 69
      Author(s): Manoj Kumar Solanki, Sabin Kumar Mishra, Jeeoot Singh
      Present paper reviews twenty different theories used for analysis of multilayered plates. The mathematical formulation of the actual physical problem of the plate subjected to mechanical loading is presented using von Karman nonlinear kinematics. These non-linear governing differential equations of equilibrium are linearized using quadratic extrapolation technique. A meshfree approach based on polynomial radial basis function is used for obtaining the solution. The results obtained for the sandwich plate are validated with other available results. It is observed that some theories under predicts the deflection by a reasonable amount. The effect varying core thickness on stresses and deflection of the sandwich plate is also presented.


      PubDate: 2016-06-15T05:42:03Z
       
  • Meshfree simulation of temperature effects on the mechanical behaviors of
           microtubules
    • Abstract: Publication date: August 2016
      Source:Engineering Analysis with Boundary Elements, Volume 69
      Author(s): Ping Xiang, L.W. Zhang, K.M. Liew
      The temperature-related mechanical behaviors of microtubules are investigated by way of the developed meshfree computational framework. An atomistic-continuum constitutive relationship is formulated for bridging-scale simulations of microtubules from polyatomic structure to continuum meshfree modeling. The establishment of a specific meshfree theory is based on high-order gradient continuity, by incorporating a higher-order Cauchy–Born rule. The influence of temperature on the critical buckling force and free vibration frequencies of microtubules is intensively studied. It is realized from the simulation results that temperature significantly affects the mechanical behaviors of microtubules. The critical buckling force and natural vibration frequencies of microtubules decrease with increases in temperature. A lower temperature will always result in a higher flexural rigidity, thus benefiting the mechanical strength of microtubules. In contrast, an elevated temperature will have negative impacts on microtubule stiffness. Microtubules with typical boundary restrictions subjected to different temperatures are included in the analysis. A series of simulation results on the critical buckling force and natural vibration frequencies of microtubules covering a wide range of microtubule lengths is presented for the purpose of the provision of engineering references.


      PubDate: 2016-06-15T05:42:03Z
       
  • Efficient analysis of sound propagation in sonic crystals using an
           ACA–MFS approach
    • Abstract: Publication date: August 2016
      Source:Engineering Analysis with Boundary Elements, Volume 69
      Author(s): L. Godinho, D. Soares, P.G. Santos
      Sonic crystals have been analysed making use of a variety of strategies, such as those based in the multiple-scattering theory (MST) or in the Finite Element Method (FEM). Recently, some works have proposed the use of the Method of Fundamental Solutions (MFS) and of the Boundary Element Method (BEM). However, considering these numerical techniques, the associated memory requirements and CPU times are usually prohibitive when problems with a large number of scatterers are considered, particularly when 3D problems are addressed. A new strategy for the solution of 3D configurations of sonic crystals is proposed here, based on the use of the MFS (formulated in the frequency domain), considering a 2.5D approach to describe the 3D model. The sound field is synthesised as a summation of much simpler 2D problems, drastically reducing the memory requirements and computational effort of the analysis. To allow the solution of very large-scale problems, with a great amount of scatterers, an Adaptive-Cross-Approximation (ACA) approach is incorporated into the MFS algorithm, rendering faster calculations and significant savings in terms of computational requirements. Examples are presented illustrating the good performance of the proposed methodology and its capacity to properly handle complex large-scale models.


      PubDate: 2016-06-15T05:42:03Z
       
  • A serendipity triangular patch for evaluating weakly singular boundary
           integrals
    • Abstract: Publication date: August 2016
      Source:Engineering Analysis with Boundary Elements, Volume 69
      Author(s): Yudong Zhong, Jianming Zhang, Yunqiao Dong, Yuan Li, Weicheng Lin, Jinyuan Tang
      Element subdivision is the most widely used method for the numerical evaluation of weakly singular integrals in three-dimensional boundary element analyses. In the traditional subdivision method, the sub-elements, which are called patches in this paper, are obtained by simply connecting the singular point with each vertex of the element. Patches with large angles at the source point may be produced and thus, a large number of Gaussian quadrature points are needed to achieve acceptable accuracy. In this paper, a serendipity triangular patch with four-node is presented to solve the problem. Case studies have been made to investigate the effect of the location of the middle node of the serendipity patch on accuracy, and an optimal location is determined. Moreover, theoretical analysis validating the optimal location is also given with a new form of polar coordinate transformation. Numerical examples are presented to compare the new patch with the conventional linear patch with respect to both accuracy and efficiency. In all cases, the results are encouraging.


      PubDate: 2016-06-15T05:42:03Z
       
  • Buckling analysis of graphene sheets embedded in an elastic medium based
           on the kp-Ritz method and non-local elasticity theory
    • Abstract: Publication date: September 2016
      Source:Engineering Analysis with Boundary Elements, Volume 70
      Author(s): Yang Zhang, L.W. Zhang, K.M. Liew, J.L. Yu
      Graphene finds application in nanoscale electronic devices, nano sensors and nanocomposites in which graphene sheets usually rest on an elastic medium. Buckling of graphene sheets can occur in such structures, which significantly influences its performance. Therefore, it is essential to investigate the buckling behavior of graphene for better engineering design and manufacture. The present work provides an element-free kp-Ritz framework to analyze the buckling behavior of graphene. The element-free kp-Ritz method is first implemented to investigate the buckling behavior of single-layered graphene sheets (SLGSs) embedded in elastic foundations, based on the classical plate theory (CLP), incorporating the non-local elasticity theory, which takes small effects into account when dealing with nanostructures. A Winkler-type model is adopted to simulate the functioning of the elastic medium. Numerical solutions for critical buckling loads of SLGSs are obtained by solving the governing differential equations derived from the principle of minimum potential energy using the element-free kp-Ritz method. The concepts of non-local parameter effects and non-local effects are distinguished. The influence of non-local parameters for both side length and aspect ratio on critical buckling loads of SLGSs is analyzed. Additionally, the effects of non-local parameters and the Winkler modulus parameter on the buckling patterns are discussed.


      PubDate: 2016-06-15T05:42:03Z
       
  • Editorial Board
    • Abstract: Publication date: August 2016
      Source:Engineering Analysis with Boundary Elements, Volume 69




      PubDate: 2016-06-15T05:42:03Z
       
  • A surface-to-surface scheme for 3D contact problems by boundary face
           method
    • Abstract: Publication date: September 2016
      Source:Engineering Analysis with Boundary Elements, Volume 70
      Author(s): Xiaomin Shu, Jianming Zhang, Lei Han, Yunqiao Dong
      The surface-to-surface contact algorithm has been proposed to overcome the drawbacks of node-to-surface algorithm in finite element method implementations. In the surface-to-surface algorithm, contact constraints are imposed between sub-elements rather than between nodes, and an auxiliary plane for each element is introduced to perform overlapping area detection. This work presents a combination of the surface-to-surface algorithm and the boundary face method (BFM) for solving contact problems in three dimensions. The BFM is based on boundary integral equation and is a truly isogeometric method, as it makes direct use of the geometric information of the bounding surface of a body. Apparently, the BFM is more suitable for solving contact problems. In our implementation, the auxiliary plane is no more necessary, but replaced by the boundary faces themselves which already exist in the BFM data structure. Our implementation is natural and can more precisely match the contact conditions between faces, and therefore, higher level of accuracy can be expected. Numerical examples presented have demonstrated the advantages of the combined method.


      PubDate: 2016-06-15T05:42:03Z
       
  • Free and forced vibration analyses using the four-node quadrilateral
           element with continuous nodal stress
    • Abstract: Publication date: September 2016
      Source:Engineering Analysis with Boundary Elements, Volume 70
      Author(s): Yongtao Yang, Li Chen, Dongdong Xu, Hong Zheng
      The recently published four-node quadrilateral element with continuous nodal stress (Quad4-CNS) is extended to free and forced vibration analyses of two-dimensional solids. The Quad4-CNS element can be regarded as a partition-of-unity (PU) based ‘FE-Meshfree’ element which inherits better accuracy, higher convergence rate, and high tolerance to mesh distortion from the meshfree methods, while preserving the Kronecker-delta property of the finite element method (FEM). Moreover, the Quad4-CNS element is free from the linear dependence problem which otherwise cripples many of the PU based finite elements. Several free and forced vibration problems are solved and the performance of the element is compared with that of the four-node isoparametric quadrilateral element (Quad4) and eight-node isoparametric quadrilateral element (Quad8). The results show that, for regular meshes, the performance of the element is superior to that of Quad4 element, and comparable to that of Quad8 element. For distorted meshes, the present element has better mesh-distortion tolerance than Quad4 and Quad8 elements.


      PubDate: 2016-06-15T05:42:03Z
       
  • A meshless solution of two dimensional multiphase flow in porous media
    • Abstract: Publication date: September 2016
      Source:Engineering Analysis with Boundary Elements, Volume 70
      Author(s): Karel Kovářík, Soňa Masarovičová, Juraj Mužík, Dana Sitányiová
      Multiphase fluid flow problems are of importance in many disciplines including hydrology and petroleum reservoir engineering. Standard methods such as the finite differences, finite volumes and expanded mixed finite elements methods use very general unstructured grids and need different grid adaptation strategies to ensure optimal solution of this non-linear problem. The meshless methods seem to be quite a good alternative to these classical mesh-based methods. In our work we used the meshless Petrov–Galerkin local method based on the pressure-saturation formulation.


      PubDate: 2016-06-15T05:42:03Z
       
  • A new approach to non-homogeneous hyperbolic boundary value problems using
           hybrid-Trefftz stress finite elements
    • Abstract: Publication date: August 2016
      Source:Engineering Analysis with Boundary Elements, Volume 69
      Author(s): Ionuţ Dragoş Moldovan
      A new approach to the solution of non-homogeneous hyperbolic boundary value problems is casted here using the hybrid-Trefftz stress/flux elements. Similarly to the Dual Reciprocity Method, the technique adopted in this paper uses a Trefftz-compliant set of functions to approximate the complementary solution of the problem and an additional trial basis to approximate its particular solution. However, the particular and complementary solutions are obtained here in a single step, and not sequentially, as typical of the Dual Reciprocity Method. The trial functions used for both particular and complementary solutions are merged together in the same basis and offered full flexibility to combine so as to recover the enforced equations in the best possible way. This option enables Trefftz-compliant functions to compensate for deficiencies of the particular solution basis, meaning that accurate total solutions can be obtained with relatively poor particular solution approximations. The formulation preserves the Hermitian, sparse and localized structure that typifies the matrix of coefficients of hybrid-Trefftz finite elements and avoids the drawbacks of the collocation procedures that arise in the Dual Reciprocity Method. Moreover, all terms of the matrix of coefficients are reduced to boundary integral expressions provided the particular solution trial functions satisfy the static problem obtained after discarding both non-homogeneous and time derivative terms from the governing equation.


      PubDate: 2016-05-10T03:29:23Z
       
  • Fast frequency sweep method for indirect boundary element models arising
           in acoustics
    • Abstract: Publication date: August 2016
      Source:Engineering Analysis with Boundary Elements, Volume 69
      Author(s): Sanda Lefteriu, Marcos Souza Lenzi, Hadrien Bériot, Michel Tournour, Wim Desmet
      This paper presents an efficient approach for computing frequency sweeps with fine increments of acoustic systems described by the variational indirect boundary element method. The matrices arising from such boundary element discretizations are fully populated and their assembly is computationally demanding as it involves the calculation of double surface integrals for each system matrix entry. Therefore, the two operations performed when computing the response at one frequency, namely assembling the system matrix and solving the associated linear system, may be of the same order of magnitude in terms of the required computational time. The proposed fast frequency sweep approach accelerates both operations. First, it avoids forming the system matrices for each individual frequency. Matrices are only assembled at a few master frequencies, while for the rest, interpolation is used on scaled quantities determined at the master frequencies. Second, it avoids solving a dense linear system at each frequency. Padé approximants constructed via the well-conditioned asymptotic waveform evaluation algorithm are used to extrapolate the response around expansion frequencies using derivative information. The proposed method was tested on an exterior acoustics application representing an academic test case, as well as on an interior/exterior application representing an industrial test case.


      PubDate: 2016-05-10T03:29:23Z
       
  • The plane waves method for axisymmetric Helmholtz problems
    • Abstract: Publication date: August 2016
      Source:Engineering Analysis with Boundary Elements, Volume 69
      Author(s): Andreas Karageorghis
      The plane waves method is employed for the solution of Dirichlet and Neumann boundary value problems for the homogeneous Helmholtz equation in two- and three-dimensional domains possessing radial symmetry. The appropriate selection of collocation points and unitary direction vectors in the method leads to circulant and block circulant coefficient matrices in two and three dimensions, respectively. We propose efficient matrix decomposition algorithms which make use of fast Fourier transforms for the solution of the systems resulting from such a discretization. In conjunction with the method of particular solutions, the method is extended to the solution of inhomogeneous axisymmetric Helmholtz problems. Several numerical examples are presented.


      PubDate: 2016-05-10T03:29:23Z
       
  • Nonlinear simulation of resonant sloshing in wedged tanks using boundary
           element method
    • Abstract: Publication date: August 2016
      Source:Engineering Analysis with Boundary Elements, Volume 69
      Author(s): Chongwei Zhang
      Nonlinear sloshing problems in wedged tanks are simulated based on the paralleled boundary element method. An improved semi-Lagrangian procedure is introduced for the free-surface updating near non-vertical tank walls. Two types of resonances are mainly considered. One is the classical resonance, which is induced by a lateral excitation on the tank. Featured sloshing phenomena in wedged tanks are observed compared with those in rectangular tanks. The other type is the Faraday waves due to the forced tank oscillation perpendicular to the undisturbed free-surface plane. Effects of the excitation frequency, acceleration amplitude, instability regions and initial free-surface disturbance on behaviours of the resonant sloshing in wedged tanks are investigated.


      PubDate: 2016-05-05T02:45:29Z
       
  • Parametric integral equation system (PIES) for 2D elastoplastic analysis
    • Abstract: Publication date: August 2016
      Source:Engineering Analysis with Boundary Elements, Volume 69
      Author(s): Agnieszka Bołtuć
      The paper presents the formalism of the parametric integral equation system (PIES) for two-dimensional elastoplastic problems and the algorithm for its numerical solution. The efficiency of the proposed approach lies in the global modeling of a plastic zone, without classic discretization into elements, using surface patches popular in computer graphics. Lagrange polynomials with various number and arrangement of interpolation nodes are used to approximate plastic strains. Three test examples are solved and the obtained results are compared with analytical and numerical solutions.


      PubDate: 2016-05-05T02:45:29Z
       
 
 
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