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  Subjects -> COMPUTER SCIENCE (Total: 2053 journals)
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COMPUTER SCIENCE (1198 journals)                  1 2 3 4 5 6 | Last

Showing 1 - 200 of 872 Journals sorted alphabetically
3D Printing and Additive Manufacturing     Full-text available via subscription   (Followers: 20)
Abakós     Open Access   (Followers: 4)
ACM Computing Surveys     Hybrid Journal   (Followers: 27)
ACM Journal on Computing and Cultural Heritage     Hybrid Journal   (Followers: 8)
ACM Journal on Emerging Technologies in Computing Systems     Hybrid Journal   (Followers: 11)
ACM Transactions on Accessible Computing (TACCESS)     Hybrid Journal   (Followers: 3)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 15)
ACM Transactions on Applied Perception (TAP)     Hybrid Journal   (Followers: 5)
ACM Transactions on Architecture and Code Optimization (TACO)     Hybrid Journal   (Followers: 9)
ACM Transactions on Autonomous and Adaptive Systems (TAAS)     Hybrid Journal   (Followers: 7)
ACM Transactions on Computation Theory (TOCT)     Hybrid Journal   (Followers: 12)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 3)
ACM Transactions on Computer Systems (TOCS)     Hybrid Journal   (Followers: 17)
ACM Transactions on Computer-Human Interaction     Hybrid Journal   (Followers: 14)
ACM Transactions on Computing Education (TOCE)     Hybrid Journal   (Followers: 5)
ACM Transactions on Design Automation of Electronic Systems (TODAES)     Hybrid Journal   (Followers: 3)
ACM Transactions on Economics and Computation     Hybrid Journal  
ACM Transactions on Embedded Computing Systems (TECS)     Hybrid Journal   (Followers: 3)
ACM Transactions on Information Systems (TOIS)     Hybrid Journal   (Followers: 19)
ACM Transactions on Intelligent Systems and Technology (TIST)     Hybrid Journal   (Followers: 7)
ACM Transactions on Interactive Intelligent Systems (TiiS)     Hybrid Journal   (Followers: 3)
ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP)     Hybrid Journal   (Followers: 9)
ACM Transactions on Reconfigurable Technology and Systems (TRETS)     Hybrid Journal   (Followers: 6)
ACM Transactions on Sensor Networks (TOSN)     Hybrid Journal   (Followers: 7)
ACM Transactions on Speech and Language Processing (TSLP)     Hybrid Journal   (Followers: 8)
ACM Transactions on Storage     Hybrid Journal  
ACS Applied Materials & Interfaces     Full-text available via subscription   (Followers: 28)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 2)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Ad Hoc Networks     Hybrid Journal   (Followers: 11)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Advanced Engineering Materials     Hybrid Journal   (Followers: 28)
Advanced Science Letters     Full-text available via subscription   (Followers: 10)
Advances in Adaptive Data Analysis     Hybrid Journal   (Followers: 7)
Advances in Artificial Intelligence     Open Access   (Followers: 15)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 19)
Advances in Computer Science : an International Journal     Open Access   (Followers: 15)
Advances in Computing     Open Access   (Followers: 2)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 51)
Advances in Engineering Software     Hybrid Journal   (Followers: 27)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 13)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 22)
Advances in Human-Computer Interaction     Open Access   (Followers: 19)
Advances in Materials Sciences     Open Access   (Followers: 14)
Advances in Operations Research     Open Access   (Followers: 12)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 6)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Remote Sensing     Open Access   (Followers: 44)
Advances in Science and Research (ASR)     Open Access   (Followers: 5)
Advances in Technology Innovation     Open Access   (Followers: 5)
AEU - International Journal of Electronics and Communications     Hybrid Journal   (Followers: 8)
African Journal of Information and Communication     Open Access   (Followers: 8)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 4)
AI EDAM     Hybrid Journal  
Air, Soil & Water Research     Open Access   (Followers: 11)
AIS Transactions on Human-Computer Interaction     Open Access   (Followers: 5)
Algebras and Representation Theory     Hybrid Journal   (Followers: 1)
Algorithms     Open Access   (Followers: 11)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 5)
American Journal of Computational Mathematics     Open Access   (Followers: 4)
American Journal of Information Systems     Open Access   (Followers: 5)
American Journal of Sensor Technology     Open Access   (Followers: 4)
Anais da Academia Brasileira de Ciências     Open Access   (Followers: 2)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 7)
Analysis in Theory and Applications     Hybrid Journal   (Followers: 1)
Animation Practice, Process & Production     Hybrid Journal   (Followers: 5)
Annals of Combinatorics     Hybrid Journal   (Followers: 4)
Annals of Data Science     Hybrid Journal   (Followers: 11)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 12)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Software Engineering     Hybrid Journal   (Followers: 13)
Annual Reviews in Control     Hybrid Journal   (Followers: 6)
Anuario Americanista Europeo     Open Access  
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applied and Computational Harmonic Analysis     Full-text available via subscription   (Followers: 1)
Applied Artificial Intelligence: An International Journal     Hybrid Journal   (Followers: 12)
Applied Categorical Structures     Hybrid Journal   (Followers: 2)
Applied Clinical Informatics     Hybrid Journal   (Followers: 2)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 11)
Applied Computer Systems     Open Access   (Followers: 2)
Applied Informatics     Open Access  
Applied Mathematics and Computation     Hybrid Journal   (Followers: 33)
Applied Medical Informatics     Open Access   (Followers: 10)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Soft Computing     Hybrid Journal   (Followers: 16)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Applied System Innovation     Open Access  
Architectural Theory Review     Hybrid Journal   (Followers: 3)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 5)
Archive of Numerical Software     Open Access  
Archives and Museum Informatics     Hybrid Journal   (Followers: 140)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5)
arq: Architectural Research Quarterly     Hybrid Journal   (Followers: 7)
Artifact     Hybrid Journal   (Followers: 2)
Artificial Life     Hybrid Journal   (Followers: 7)
Asia Pacific Journal on Computational Engineering     Open Access  
Asia-Pacific Journal of Information Technology and Multimedia     Open Access   (Followers: 1)
Asian Journal of Computer Science and Information Technology     Open Access  
Asian Journal of Control     Hybrid Journal  
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
Australian Educational Computing     Open Access   (Followers: 1)
Automatic Control and Computer Sciences     Hybrid Journal   (Followers: 4)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Automatica     Hybrid Journal   (Followers: 11)
Automation in Construction     Hybrid Journal   (Followers: 6)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 9)
Basin Research     Hybrid Journal   (Followers: 5)
Behaviour & Information Technology     Hybrid Journal   (Followers: 52)
Big Data and Cognitive Computing     Open Access   (Followers: 2)
Biodiversity Information Science and Standards     Open Access  
Bioinformatics     Hybrid Journal   (Followers: 288)
Biomedical Engineering     Hybrid Journal   (Followers: 15)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 21)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 37)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 45)
British Journal of Educational Technology     Hybrid Journal   (Followers: 146)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 12)
c't Magazin fuer Computertechnik     Full-text available via subscription   (Followers: 1)
CALCOLO     Hybrid Journal  
Calphad     Hybrid Journal  
Canadian Journal of Electrical and Computer Engineering     Full-text available via subscription   (Followers: 14)
Capturing Intelligence     Full-text available via subscription  
Catalysis in Industry     Hybrid Journal   (Followers: 1)
CEAS Space Journal     Hybrid Journal   (Followers: 2)
Cell Communication and Signaling     Open Access   (Followers: 2)
Central European Journal of Computer Science     Hybrid Journal   (Followers: 5)
CERN IdeaSquare Journal of Experimental Innovation     Open Access   (Followers: 3)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 14)
ChemSusChem     Hybrid Journal   (Followers: 7)
China Communications     Full-text available via subscription   (Followers: 8)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
CIN Computers Informatics Nursing     Full-text available via subscription   (Followers: 11)
Circuits and Systems     Open Access   (Followers: 15)
Clean Air Journal     Full-text available via subscription   (Followers: 1)
CLEI Electronic Journal     Open Access  
Clin-Alert     Hybrid Journal   (Followers: 1)
Cluster Computing     Hybrid Journal   (Followers: 1)
Cognitive Computation     Hybrid Journal   (Followers: 4)
COMBINATORICA     Hybrid Journal  
Combinatorics, Probability and Computing     Hybrid Journal   (Followers: 4)
Combustion Theory and Modelling     Hybrid Journal   (Followers: 14)
Communication Methods and Measures     Hybrid Journal   (Followers: 12)
Communication Theory     Hybrid Journal   (Followers: 21)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Algebra     Hybrid Journal   (Followers: 3)
Communications in Computational Physics     Full-text available via subscription   (Followers: 2)
Communications in Partial Differential Equations     Hybrid Journal   (Followers: 3)
Communications of the ACM     Full-text available via subscription   (Followers: 52)
Communications of the Association for Information Systems     Open Access   (Followers: 16)
COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering     Hybrid Journal   (Followers: 3)
Complex & Intelligent Systems     Open Access   (Followers: 1)
Complex Adaptive Systems Modeling     Open Access  
Complex Analysis and Operator Theory     Hybrid Journal   (Followers: 2)
Complexity     Hybrid Journal   (Followers: 6)
Complexus     Full-text available via subscription  
Composite Materials Series     Full-text available via subscription   (Followers: 8)
Computación y Sistemas     Open Access  
Computation     Open Access  
Computational and Applied Mathematics     Hybrid Journal   (Followers: 2)
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2)
Computational and Mathematical Organization Theory     Hybrid Journal   (Followers: 2)
Computational and Structural Biotechnology Journal     Open Access   (Followers: 2)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 9)
Computational Astrophysics and Cosmology     Open Access   (Followers: 1)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 11)
Computational Chemistry     Open Access   (Followers: 2)
Computational Cognitive Science     Open Access   (Followers: 2)
Computational Complexity     Hybrid Journal   (Followers: 4)
Computational Condensed Matter     Open Access  
Computational Ecology and Software     Open Access   (Followers: 9)
Computational Economics     Hybrid Journal   (Followers: 9)
Computational Geosciences     Hybrid Journal   (Followers: 15)
Computational Linguistics     Open Access   (Followers: 23)
Computational Management Science     Hybrid Journal  
Computational Mathematics and Modeling     Hybrid Journal   (Followers: 8)
Computational Mechanics     Hybrid Journal   (Followers: 5)
Computational Methods and Function Theory     Hybrid Journal  
Computational Molecular Bioscience     Open Access   (Followers: 2)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Particle Mechanics     Hybrid Journal   (Followers: 1)
Computational Research     Open Access   (Followers: 1)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computational Science and Techniques     Open Access  
Computational Statistics     Hybrid Journal   (Followers: 14)
Computational Statistics & Data Analysis     Hybrid Journal   (Followers: 30)
Computer     Full-text available via subscription   (Followers: 94)
Computer Aided Surgery     Hybrid Journal   (Followers: 6)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 8)
Computer Communications     Hybrid Journal   (Followers: 16)
Computer Engineering and Applications Journal     Open Access   (Followers: 5)
Computer Journal     Hybrid Journal   (Followers: 9)
Computer Methods in Applied Mechanics and Engineering     Hybrid Journal   (Followers: 23)
Computer Methods in Biomechanics and Biomedical Engineering     Hybrid Journal   (Followers: 12)
Computer Methods in the Geosciences     Full-text available via subscription   (Followers: 2)
Computer Music Journal     Hybrid Journal   (Followers: 19)

        1 2 3 4 5 6 | Last

Journal Cover Advances in Engineering Software
  [SJR: 0.812]   [H-I: 49]   [27 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0965-9978
   Published by Elsevier Homepage  [3175 journals]
  • Suspension mechanical performance and vehicle ride comfort applying a
           novel jounce bumper based on negative Poisson's ratio structure
    • Authors: Yuanlong Wang; Wanzhong Zhao; Guan Zhou; Qiang Gao; Chunyan Wang
      Pages: 1 - 12
      Abstract: Publication date: August 2018
      Source:Advances in Engineering Software, Volume 122
      Author(s): Yuanlong Wang, Wanzhong Zhao, Guan Zhou, Qiang Gao, Chunyan Wang
      Comparing with traditional honeycomb structures, Negative Poisson's Ratio (NPR) structures had better mechanical performances in some certain respects, especially the shear modulus and fracture toughness. However, few publications focused on the cylinder-shape NPR structure, which influence the diversity and possibility of NPR structure applications. In this paper, a cylindrical NPR structure was introduced and applied as a suspension jounce bumper in order to solve the issue that the ideal uniaxial compression load-displacement curve sometimes cannot be realized by traditional Polyurethane (PU) jounce bumper. The load-displacement curve of NPR jounce bumper was proved to be smoother and more ideal than that of traditional jounce bumper. Nevertheless, the influences of NPR jounce bumper on the suspension mechanical performance and vehicle ride comfort were not comprehended yet. In this study, the traditional and NPR jounce bumpers were both assembled into virtual prototypes of Macpherson, double wishbone and multi-link suspensions to conduct single wheel travel virtual tests. The results indicated that NPR jounce bumper can achieve more ideal wheel force vs. jounce height curve without adjusting free travel, which is beneficial to spare precise suspension space. Furthermore, a jounce bumper evaluation method using pulse ride comfort was proposed in this paper. The virtual ride comfort tests of travelling through bump and pothole were conducted using established vehicle virtual prototype. The maximum vertical accelerations and weighted root mean square (RMS) of acceleration of vehicle centroid at most speeds were reduced applying NPR jounce bumper. Thus, the NPR jounce bumper can apparently improve vehicle ride comfort.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.04.001
      Issue No: Vol. 122 (2018)
       
  • Time delay control of cable-driven manipulators with adaptive
           fractional-order nonsingular terminal sliding mode
    • Authors: Yaoyao Wang; Fei Yan; Surong Jiang; Bai Chen
      Pages: 13 - 25
      Abstract: Publication date: July 2018
      Source:Advances in Engineering Software, Volume 121
      Author(s): Yaoyao Wang, Fei Yan, Surong Jiang, Bai Chen
      For the high performance control of cable-driven manipulators, a novel time delay control (TDC) scheme with adaptive fractional-order nonsingular terminal sliding mode (AFONTSM) is presented and studied in this work. The presented control scheme uses time delay estimation (TDE) as its basic framework, which can effectively obtain a fascinating model-free feature just using the time-delayed information of the closed-loop control system. Afterwards, a novel AFONTSM control scheme is applied to provide with good comprehensive performance under complicated lumped disturbance in both reaching and sliding phases. The presented control method can be easily applied in real situations thanks to TDE, meanwhile satisfactory control performance can be guaranteed benefiting from the adopted AFONTSM error dynamics. Stability analysis is given based on Lyapunov stability theory. Finally, the effectiveness and superiorities of our newly designed control scheme are validated through 2-DOFs (degree of freedoms) comparative simulations and experiments.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.03.004
      Issue No: Vol. 121 (2018)
       
  • A new approach in designing of local controlled developable H-Bézier
           surfaces
    • Authors: Gang Hu; Junli Wu; Xinqiang Qin
      Pages: 26 - 38
      Abstract: Publication date: July 2018
      Source:Advances in Engineering Software, Volume 121
      Author(s): Gang Hu, Junli Wu, Xinqiang Qin
      To solve the problem of shape adjustment for developable surfaces, we propose a novel method for constructing local controlled generalized developable H-Bézier surfaces with shape parameters. The generalized developable H-Bézier surfaces are designed by using control planes with generalized H-Bézier basis functions and their shapes can be adjusted by altering the values of shape parameters. When the shape parameters assume different values, a family of developable H-Bézier surfaces can be constructed, which retain the characteristics of the developable Bézier surfaces. Furthermore, we derive the necessary and sufficient conditions for G1 continuity, Farin-Boehm G2 continuity and G2 Beta continuity between two adjacent generalized developable H-Bézier surfaces. Finally, some properties of the new developable surfaces are discussed, and the influence rules of shape parameters on the new developable surfaces are studied. Modeling examples provided show that the proposed methods are effective and hence can greatly improve problem-solving abilities in engineering appearance design by adjusting the position and shape of developable surfaces.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.03.003
      Issue No: Vol. 121 (2018)
       
  • π-BEM: A flexible parallel implementation for adaptive, geometry aware,
           and high order boundary element methods
    • Authors: Nicola Giuliani; Andrea Mola; Luca Heltai
      Pages: 39 - 58
      Abstract: Publication date: July 2018
      Source:Advances in Engineering Software, Volume 121
      Author(s): Nicola Giuliani, Andrea Mola, Luca Heltai
      Many physical phenomena can be modelled using boundary integral equations, and discretised using the boundary element method (BEM). Such models only require the discretisation of the boundary of the domain, making the setup of the simulation straightforward and lowering the number of degrees of freedom. However, while many parallel efficient libraries are available for the Finite Element Method (FEM), the implementation of scalable BEM solvers still poses many challenges. We present the open source framework π-BEM (where π stands for parallel): a novel boundary element method solver, combining distributed and shared memory paradigms to achieve high scalability. π-BEM exploits high performance libraries and graph partitioning tools to deliver a parallel solver employing automatic domain decomposition, high order elements, local refinement capabilities, and exact geometry-adaptivity (using CAD files). A preliminary fast multipole accelerator is included in the implementation. Every aspect of the library is modular and easily extendible by the community. We discuss the internal structure of the code, and present some examples to demonstrate the reliability and scalability of our implementation.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.03.008
      Issue No: Vol. 121 (2018)
       
  • Reliability-based design optimization of nonlinear inelastic trusses using
           improved differential evolution algorithm
    • Authors: Viet-Hung Truong; Seung-Eock Kim
      Pages: 59 - 74
      Abstract: Publication date: July 2018
      Source:Advances in Engineering Software, Volume 121
      Author(s): Viet-Hung Truong, Seung-Eock Kim
      A robust method for sizing reliability-based design optimization (RBDO) of truss structures is developed by integrating nonlinear inelastic analysis, a structural reliability analysis method, and a proposed optimization method based on differential evolution (DE) algorithm. Both discrete and continuous optimizations are considered. Compared to conventional DE, three main improvements are introduced in the proposed optimization method such as: (1) a new mutation scheme based on p-best strategy to balance between local and global searches; (2) modifications of the scale factor and crossover rate parameters; (3) a multi-comparison technique to reduce the useless objective function evaluations. 20 test functions and 4 real-world examples are first considered to demonstrate the performance of the proposed optimization method for deterministic optimization problems. 3 nonlinear inelastic truss structures are then carried out to investigate the robustness of proposed RBDO method.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.03.006
      Issue No: Vol. 121 (2018)
       
  • Numerical formulation based on moving mesh method for vehicle–bridge
           interaction
    • Authors: Fabrizio Greco; Paolo Lonetti
      Pages: 75 - 83
      Abstract: Publication date: July 2018
      Source:Advances in Engineering Software, Volume 121
      Author(s): Fabrizio Greco, Paolo Lonetti
      A finite element modeling based on a moving mesh strategy is developed to predict Vehicle–Bridge Interaction (VBI) in moving load applications. The formulation is based on an Arbitrary Lagrangian–Eulerian (ALE) approach, which is able to reproduce the vehicle motion on the basis of a fixed-referential system and moving coordinate variables, representing the positions of the external system. Conceptually, the vehicle and the bridge are considered as an integrated system, in which wheel-bridge interaction as well as the internal forces are implemented by means of moving interface elements. The governing equations of the VBI are derived in the referential coordinate system, whereas the ones associated to bridge structure are not modified from the conventional formulation. Such task is achieved by means of proper projection operators, which define the mapping between the referential and material configurations, reproducing the contact forces between the substructures. The proposed model is quite general to be endorsed in classical FE approach, since it does not require specialized connections with conventional structural formulations. The accuracy and efficiency are verified by means of comparisons with existing numerical results available from the literature, including cases in which the bridge structure is affected by damage phenomena.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.03.013
      Issue No: Vol. 121 (2018)
       
  • Assembly sequences plan generation using features simplification
    • Authors: Riadh Ben Hadj; Imen Belhadj; Moez Trigui; Nizar Aifaoui
      Pages: 1 - 11
      Abstract: Publication date: May 2018
      Source:Advances in Engineering Software, Volume 119
      Author(s): Riadh Ben Hadj, Imen Belhadj, Moez Trigui, Nizar Aifaoui
      The automatic generation of the assembly/disassembly plan is considered a topical problem in the computer-aided tools area. The main problem of the major proposed approaches is the excessive processing time to treat the whole assembly model. This paper proposes a simplification approach of CAD models to make the generation of assembly plan easy. The developed method begins by the elimination of connection elements to obtain a simplified assembly sequence. A case-based reasoning algorithm is, then, developed to insert the entire eliminated elements in the global assembly sequence plan. Two examples of CAD assembly are treated in order to compare and validate the obtained results.

      PubDate: 2018-02-05T00:15:34Z
      DOI: 10.1016/j.advengsoft.2018.01.008
      Issue No: Vol. 119 (2018)
       
  • A modified strain-controlled reference stress approach for submarine
           pipelines under large-scale plastic strain
    • Authors: Xiaoxin Zhao; Lianyong Xu; Hongyang Jing; Lei Zhao; Jiangzhong Huang
      Pages: 12 - 20
      Abstract: Publication date: May 2018
      Source:Advances in Engineering Software, Volume 119
      Author(s): Xiaoxin Zhao, Lianyong Xu, Hongyang Jing, Lei Zhao, Jiangzhong Huang
      The reel-lay approach is widely applied in submarine pipelines. During the process of reeling and unreeling, pipelines are subjected to nominal strain of 1–4%. In this study, various pipeline geometries and crack dimensions were calculated using a finite element analysis and analytical solution under strain-controlled boundary conditions. A modified reference stress approach was applied under strain-controlled boundary conditions using a derived implicit analytical solution of the nominal stress. The limit load solution was modified through a γ factor based on the finite element analysis under strain-controlled boundary conditions. A regression analysis of γ was conducted and an empirical formula was determined. The modified strain-controlled reference approach is in contrast to other ECA methods and proved to be closer to the finite element analysis results.

      PubDate: 2018-02-26T01:24:18Z
      DOI: 10.1016/j.advengsoft.2018.01.010
      Issue No: Vol. 119 (2018)
       
  • A new continuous fractional-order nonsingular terminal sliding mode
           control for cable-driven manipulators
    • Authors: Yaoyao Wang; Surong Jiang; Bai Chen; Hongtao Wu
      Pages: 21 - 29
      Abstract: Publication date: May 2018
      Source:Advances in Engineering Software, Volume 119
      Author(s): Yaoyao Wang, Surong Jiang, Bai Chen, Hongtao Wu
      To ensure satisfactory control performance for the cable-driven manipulators under complex lumped uncertainties, a new continuous fractional-order nonsingular terminal sliding mode (CFONTSM) control scheme based on time delay estimation (TDE) is proposed and studied in this paper. The proposed control scheme contains three elements, a TDE element adopted to suitably cancel out the unknown lumped dynamics with purposely time-delayed signals of the closed-loop control system, a newly proposed FONTSM manifold adopted to realize finite-time convergence in the sliding mode phase and a fast-TSM-type reaching law adopted to ensure finite-time convergence in the reaching phase. The proposed control scheme is model-free and no longer needs system dynamics benefiting from TDE, which is very suitable and easy to use in practical applications. Meanwhile, high precision, fast convergence and good robustness against lumped uncertainties are ensured thanks to the newly proposed FONTSM manifold and adopted fast-TSM-type reaching law. Integrated stability analysis of the closed-loop control system is presented based on Lyapunov stability theory. Finally, the effectiveness of our proposed control scheme is demonstrated by comparative 2-DoFs (degrees-of-freedom) simulation and experiments.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.01.011
      Issue No: Vol. 119 (2018)
       
  • DEM simulation of bionic subsoilers (tillage depth >40 cm) with drag
           reduction and lower soil disturbance characteristics
    • Authors: Jiyu Sun; Yueming Wang; Yunhai Ma; Jin Tong; Zhijun Zhang
      Pages: 30 - 37
      Abstract: Publication date: May 2018
      Source:Advances in Engineering Software, Volume 119
      Author(s): Jiyu Sun, Yueming Wang, Yunhai Ma, Jin Tong, Zhijun Zhang
      Successive years of mechanical operations and conservation tillage in Northeast China have made subsoiling necessary, and the tillage depth can be no less than 40 cm. In this paper, a bionic design method was used to reduce subsoiler energy consumption and soil disturbance. The bionic structural elements, i.e., triangular prism (BTP) and partial circular column (BPCC), were inspired by the placoid scale rib structure of shark skin, which has low drag. These elements were then applied to the subsoiler to reduce energy consumption. Six types of bionic subsoilers were designed. Discrete element modeling (DEM) was used to simulate and analyze the interactions of the bionic subsoilers and an ordinary subsoiler (O-S) with the soil. The results showed that bionic subsoilers with a shank and BTP in the horizontal direction of motion (S-T-H) and tines with the BTP parallel to the centerline (T-T) had lower draft requirements and energy consumption than the other designs. The draft requirements and energy consumption of S-T-H subsoilers with different height-to-lateral-rib-spacing (h/s) ratios were then compared. The subsoiler with a bionic element h/s of 0.57 (S-T-H-0.57) had a lower draft requirement (1292.59 N) and a lower total energy requirement (23.48 J) than the other designs. A soil disturbance analysis demonstrated that S-T-H-0.57-T-T (bionic elements arranged in both the shank and tine) provided superior benefits in terms of root growth and improved crop stress resistance. The result is consistent with the mechanical analysis of the riblet, which will be helpful for designing new subsoilers with reduced drag and soil disturbance.

      PubDate: 2018-02-26T01:24:18Z
      DOI: 10.1016/j.advengsoft.2018.02.001
      Issue No: Vol. 119 (2018)
       
  • Model-free based adaptive nonsingular fast terminal sliding mode control
           with time-delay estimation for a 12 DOF multi-functional lower limb
           exoskeleton
    • Authors: Shuaishuai Han; Haoping Wang; Yang Tian
      Pages: 38 - 47
      Abstract: Publication date: May 2018
      Source:Advances in Engineering Software, Volume 119
      Author(s): Shuaishuai Han, Haoping Wang, Yang Tian
      The design of a 12 DOF lower limb multi-functional exoskeleton is realized in SolidWorks with the analysis of kinematics. For controller design, this paper presents the model-free based adaptive nonsingular fast terminal sliding mode control which comprises three parts: the intelligent PI controller, time-delay estimation, and adaptive sliding mode compensator. The proposed control strategy drives tracking errors to a nonsingular fast terminal sliding surface and realizes fast convergence in finite time. The designed adaptive law approximates the upper bound of estimation error in time-delay estimation and thus it reduces the fundamental chattering on the switching manifold. The stability of controller is verified by using Lyapunov theory. To validate the proposed method, the virtual prototype is transferred to MATLAB/SimMechanics as a platform for co-simulation. The proposed method shows improved tracking performance compared with the existing model free controller in co-simulations.

      PubDate: 2018-02-26T01:24:18Z
      DOI: 10.1016/j.advengsoft.2018.01.004
      Issue No: Vol. 119 (2018)
       
  • An efficient approach for optimal sensor placement and damage
           identification in laminated composite structures
    • Authors: D. Dinh-Cong; H. Dang-Trung; T. Nguyen-Thoi
      Pages: 48 - 59
      Abstract: Publication date: May 2018
      Source:Advances in Engineering Software, Volume 119
      Author(s): D. Dinh-Cong, H. Dang-Trung, T. Nguyen-Thoi
      This paper proposed an efficient approach for optimal sensor placement and damage identification in laminated composite structures. This approach first utilized a model reduction technique, namely iterated improved reduced system (IIRS) method, to develop a reduced order model for optimal sensor placement (OSP), and then the OSP strategy using Jaya algorithm is conducted by formulating and solving an optimization problem for finding the best sensor locations. The objective function of the optimization problem is defined based on the correlation between the flexibility matrix obtained from an original finite element model and the corresponding one calculated from IIRS method. Next, the approach uses the measured incomplete modal data from optimized sensor locations for detecting and assessing any stiffness reduction induced by damage. In order to do this, the damage identification problem is formulated as an optimization problem where the damage extent of elements and the modal flexibility change are taken as the continuous design variables and the objective function, respectively. The Jaya algorithm is again adopted to solve the optimization problem for determining the actual damage sites and extents. Numerical simulations of a three cross-ply (0°/90°/0°) beam and a four-layer (0°/90°/90°/0°) laminated composite plate are carried out to demonstrate the applicability and efficiency of the proposed approach.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.02.005
      Issue No: Vol. 119 (2018)
       
  • An effective and user-friendly web application for the collaborative
           analysis of steel joints
    • Authors: J. Gracia; E. Bayo
      Pages: 60 - 67
      Abstract: Publication date: May 2018
      Source:Advances in Engineering Software, Volume 119
      Author(s): J. Gracia, E. Bayo
      The Internet has increased its potential exponentially since its inception. This progress has been possible due to new standards and technologies, which have also allowed the development of a new type of web applications that are fully integrated in web browsers. In addition, structural analysis has become a collaborative task in which different people have to share information and outputs of analysis programs. In this paper, an effective and user-friendly web application for the collaborative analysis of steel joints is presented. The latest cutting edge technologies in the Internet are used to address fundamental issues inherent in structural analysis software such as visualisation, interaction, and structural evaluation. Specifically, WebGL API, part of the HTML5 standard, is used to solve the visualisation issues of the proposed application. A rigorous analysis of simple and rigid structural joints is performed according to the standards and criteria set by the Eurocode 3.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.02.007
      Issue No: Vol. 119 (2018)
       
  • Overview of the incompressible Navier–Stokes simulation capabilities
           in the MOOSE framework
    • Authors: John W. Peterson; Alexander D. Lindsay; Fande Kong
      Pages: 68 - 92
      Abstract: Publication date: May 2018
      Source:Advances in Engineering Software, Volume 119
      Author(s): John W. Peterson, Alexander D. Lindsay, Fande Kong
      The Multiphysics Object Oriented Simulation Environment (MOOSE) framework is a high-performance, open source, C++ finite element toolkit developed at Idaho National Laboratory. MOOSE was created with the aim of assisting domain scientists and engineers in creating customizable, high-quality tools for multiphysics simulations. While the core MOOSE framework itself does not contain code for simulating any particular physical application, it is distributed with a number of physics “modules” which are tailored to solving e.g. heat conduction, phase field, and solid/fluid mechanics problems. In this report, we describe the basic equations, finite element formulations, software implementation, and regression/verification tests currently available in MOOSE’s navier_stokes module for solving the Incompressible Navier-Stokes (INS) equations.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.02.004
      Issue No: Vol. 119 (2018)
       
  • Fast sensitivity reanalysis methods assisted by Independent Coefficients
           and Indirect Factorization Updating strategies
    • Authors: Juanjuan Liu; Hu Wang
      Pages: 93 - 102
      Abstract: Publication date: May 2018
      Source:Advances in Engineering Software, Volume 119
      Author(s): Juanjuan Liu, Hu Wang
      In this study, the novel sensitivity reanalysis methods are suggested to obtain the static displacement sensitivity to local modifications efficiently. Details of displacement sensitivity formulations are deduced from the displacement reanalysis equations of Independent Coefficients (IC) and Indirect Factorization Updating (IFU) strategies. Moreover, the performances of the proposed sensitivity reanalysis methods are investigated to compare with Combined Approximation (CA) methods. Different numerical examples and efficient comparison are performed to confirm the accuracy and efficiency of the proposed methods. As a result, the proposed sensitivity reanalysis methods are proved to be more efficient with large scale problems and the accuracy of modified Degrees of Freedoms (DOFs) can be guaranteed as well.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.02.009
      Issue No: Vol. 119 (2018)
       
  • An adaptive isogeometric boundary element method for predicting the
           effective thermal conductivity of steady state heterogeneity
    • Authors: Y.P. Gong; C.Y. Dong; X.Y. Qu
      Pages: 103 - 115
      Abstract: Publication date: May 2018
      Source:Advances in Engineering Software, Volume 119
      Author(s): Y.P. Gong, C.Y. Dong, X.Y. Qu
      This work presents an adaptive isogeometric boundary element method (IGBEM) for the calculation of effective thermal conductivity of steady state heterogeneities. Based on the generalized self-consistent scheme (GSCS), some integral equation formulations which only contain the unknown temperatures on the interface are used to calculate the effective thermal conductivity of steady state composites. In our approach, the geometries of the inclusion and original matrix are described using NURBS basis functions. The advantage over currently used methods is that no geometrical errors exist in the analysis process. And the geometry data in the isogeometric GSCS model can be taken directly from CAD programs. In addition, based on the upper bound of the relative error of the Gaussian quadrature formula, an adaptive integration method is used to compute the boundary integrals, which makes the computation of the integrals easier and more efficient at optimal computational cost. The comparisons between the results obtained by the present method and the existing counterparts are carried out and the good agreement can be observed.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.03.001
      Issue No: Vol. 119 (2018)
       
  • NE-IIBEFM for problems with body forces: A seamless integration of the
           boundary type meshfree method and the NURBS boundary in CAD
    • Authors: Qiao Wang; Wei Zhou; Yonggang Cheng; Gang Ma; Xiaolin Chang; E. Chen
      Pages: 1 - 17
      Abstract: Publication date: April 2018
      Source:Advances in Engineering Software, Volume 118
      Author(s): Qiao Wang, Wei Zhou, Yonggang Cheng, Gang Ma, Xiaolin Chang, E. Chen
      A NURBS-enhanced interpolating boundary element-free method (NE-IIBEFM) is proposed by coupling the meshfree method with the non-uniform rational B-spline (NURBS). The NURBS plays an essential role in computer aided design (CAD) whereby it can be used as the bridge between boundary type meshless method and CAD, which is convenient and is widely utilized in engineering. The NURBS basis functions used in CAD packages for geometry construction are applied to describe the boundary in the numerical procedure. Thus, the geometry of the curve can be reproduced exactly at all stages. The boundary integral cells and nodes are defined from the knot vector in NURBS, and both the open and closed curves are considered. The fields are approximated by an improved interpolating moving least square method, in which the obtained shape functions have the property of delta function. Thus, the boundary conditions can be imposed directly. A line integration method without domain discretization is further coupled with the proposed method for the treatment of domain integrals for problems with body forces.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.01.002
      Issue No: Vol. 118 (2018)
       
  • Integrated probabilistic modeling method for transient opening height
           prediction of check valves in oil-gas multiphase pumps
    • Authors: Hongying Deng; Yi Liu; Ping Li; Yi Ma; Shengchang Zhang
      Pages: 18 - 26
      Abstract: Publication date: April 2018
      Source:Advances in Engineering Software, Volume 118
      Author(s): Hongying Deng, Yi Liu, Ping Li, Yi Ma, Shengchang Zhang
      To ensure the reliability of oil-gas multiphase pumps, it is necessary to model the relationship between the transient opening height of the check valve and multiphase transportation conditions. However, the choice of a suitable turbulence model is not straightforward for the widely used computational fluid dynamics (CFD) method. Additionally, the CFD models are still not easy to be validated experimentally because the transient opening motion is difficult to be accurately measured for its quick and nonlinear characteristics. In this work, an integrated probabilistic modeling (IPM) method is proposed to predict the transient opening height of the check valve in oil-gas multiphase pumps. First, candidate CFD transient models with different turbulence models are adopted to provide initial training data for several Gaussian process regression (GPR) models. Then, a probabilistic index of the trained GPR models is formulated to assess their reliability. Consequently, without knowing the actual values, a suitable GPR model is chosen from the candidates for online prediction of a new condition. Moreover, instead of the time-consuming CFD design process, a better CFD turbulence model can be selected efficiently. The superiority of IPM is demonstrated using simulation and experiments.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.01.003
      Issue No: Vol. 118 (2018)
       
  • Efficient approach to database integration for an aerospace vehicle design
           and certification framework
    • Authors: Aye Aye Maw; Tun Lwin; Maxim Tyan; Jae-Woo Lee; Sangho Kim
      Pages: 27 - 34
      Abstract: Publication date: April 2018
      Source:Advances in Engineering Software, Volume 118
      Author(s): Aye Aye Maw, Tun Lwin, Maxim Tyan, Jae-Woo Lee, Sangho Kim
      The integration of distributed data sources is one of the main problems of engineering software. The data integration process for a heterogeneous legacy system is a key aspect of the development of a computerized system and in the integration of a design framework. In this research, our approach to data integration focuses on developing system-building techniques for efficient data integration queries. Keyword-based data searching is investigated and applied within a database for a design framework. A database table connector (DTC) wrapper program is implemented based on the use of data integration processes and keyword-based searching. The DTC provides data integration for various data resources from legacy programs and database management systems using SQL querying. The DTC enables designers and developers to rapidly and efficiently develop integration frameworks for different data resources. This paper also describes the implementation and deployment of the Certification and Aircraft Design Integration System framework, which integrates various analysis and optimization codes, computer-aided design software and database management systems. Multiple data types are used within the framework, including databases, spreadsheets, flat files, XML files and personal data management. Several aircraft design and optimization problems are successfully solved using the developed framework.

      PubDate: 2018-02-26T01:24:18Z
      DOI: 10.1016/j.advengsoft.2018.01.001
      Issue No: Vol. 118 (2018)
       
  • Development of a finite element/discontinuous Galerkin/level set approach
           for the simulation of incompressible two phase flow
    • Authors: Puyang Gao; Jie Ouyang; Wen Zhou
      Pages: 45 - 59
      Abstract: Publication date: April 2018
      Source:Advances in Engineering Software, Volume 118
      Author(s): Puyang Gao, Jie Ouyang, Wen Zhou
      In this paper, we present a combined finite element/ discontinuous Galerkin/ level set method to simulate the incompressible two phase flow. The level set method is employed to capture the moving interface because of its simplicity and efficiency when dealing with the significant interface deformations. Due to the hyperbolic nature of the level set equation and the level set re-initialization equation, we apply the second order Runge Kutta Discontinuous Galerkin (RKDG) method to get the stable and precise results. Moreover, in order to obtain the accurate velocity field, the hybrid continuous and discontinuous Galerkin approach is utilized to solve the incompressible Navier–Stokes equations. In our combined method, there is no need to re-initialize the level set function in every time step and the re-initialization process is implemented after suitable time steps. The desirable mass conservation property is able to be guaranteed with a mass correction technique in the combined algorithm. In addition, the stabilization terms can be avoided in the whole computational process. Several challenging problems, i.e., a rising bubble, the dam-break flow, the Rayleigh–Taylor instability, and the complex metal casting process in the engineering applications are investigated to evaluate the feasibility, validity and practicability of our approach for solving the problem of the incompressible two phase flow.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.01.006
      Issue No: Vol. 118 (2018)
       
  • Singular Value Decomposition used for compression of results from the
           Finite Element Method
    • Authors: Štěpán Beneš; Jaroslav Kruis
      Pages: 8 - 17
      Abstract: Publication date: March 2018
      Source:Advances in Engineering Software, Volume 117
      Author(s): Štěpán Beneš, Jaroslav Kruis
      A complex finite element analysis can produce large amount of data that is problematic to post-process in reasonable time. This paper describes application of Singular Value Decomposition (SVD) to the compression of results from finite element solvers. Although the idea of image compression method is an inspiration for this research work, the SVD compression algorithm used for compression of images cannot be directly used for FEM results. Differences and implementation challenges are discussed in the text. Quality of approximation is more important in scientific field than in computer graphics where the most significant factor is the human perception of the resulting image. Error estimation methods used during compression of finite element results are presented. The focus is also on the algorithm performance. SVD is a very computational intensive method. Therefore, various optimization techniques were investigated, e.g. randomized SVD. The method leads to the lower memory consumption, 10% of the original size or less, with negligible compression error.

      PubDate: 2018-02-05T00:15:34Z
      DOI: 10.1016/j.advengsoft.2017.12.007
      Issue No: Vol. 117 (2018)
       
  • A new data-driven design methodology for mechanical systems with high
           dimensional design variables
    • Authors: Xianping Du; Feng Zhu
      Pages: 18 - 28
      Abstract: Publication date: March 2018
      Source:Advances in Engineering Software, Volume 117
      Author(s): Xianping Du, Feng Zhu
      Complicated engineering products such as cars with a large number of components can be regarded as big data systems, where the vast amount of dependent and independent design variables must be considered systematically during the product development. To design such a system with high-dimensional design variables, this study aims at developing a novel methodology based on data mining theory, and it is implemented through designing a crashworthy passenger car, which is a multi-level (system – components) complicated system. Decision tree technique was used to mine the crash simulation datasets to identify the key design variables with most significant effect on the vehicular energy absorption response and determine the range of their values. In this way, the design space can be significantly reduced and the high-dimensional design problem is greatly simplified. The results suggest that the data mining based approach can be used to design a complicated structure with multiple parameters effectively and efficiently. Compared with the traditional design method, the new approach could simplify and speed up the design process without significant influence on the accuracy.

      PubDate: 2018-02-05T00:15:34Z
      DOI: 10.1016/j.advengsoft.2017.12.006
      Issue No: Vol. 117 (2018)
       
  • A plane model of the interaction of a vehicle with the road infrastructure
    • Authors: J.A. Romero; A.A. Lozano-Guzmán; S.A. Obregón-Biosca; E. Betanzo-Quezada
      Pages: 46 - 58
      Abstract: Publication date: March 2018
      Source:Advances in Engineering Software, Volume 117
      Author(s): J.A. Romero, A.A. Lozano-Guzmán, S.A. Obregón-Biosca, E. Betanzo-Quezada
      In road transportation, bridges´ deck exhibit large deflections when compared with those of the pavements. The interaction of vehicles with these two types of road infrastructures signifies enormous costs for maintaining the whole infrastructure in economic operational conditions. In this paper, an integrated model for simulating the vehicle – infrastructure coupled interaction, is proposed. While the infrastructure model is based upon FEM, the vehicle considers a multibody model. A parametric analysis is carried out to analyse the effect of vehicle and infrastructure operational conditions, as well as vehicle design characteristics, on bridge and flexible pavement dynamic responses.

      PubDate: 2018-02-26T01:24:18Z
      DOI: 10.1016/j.advengsoft.2017.03.007
      Issue No: Vol. 117 (2018)
       
  • Numerical modeling of steel fillet welded joint
    • Authors: Martin Krejsa; Jiri Brozovsky; David Mikolasek; Premysl Parenica; Jakub Flodr; Alois Materna; Radim Halama; Jaroslav Kozak
      Pages: 59 - 69
      Abstract: Publication date: March 2018
      Source:Advances in Engineering Software, Volume 117
      Author(s): Martin Krejsa, Jiri Brozovsky, David Mikolasek, Premysl Parenica, Jakub Flodr, Alois Materna, Radim Halama, Jaroslav Kozak
      The paper is focused on the numerical modeling of steel bearing elements and their verification using experiment. Currently, for the stress-strain analysis of the elements supporting structures it is possible to use many commercial software systems, based on the finite element method - FEM. It is important to to check and compare the results of FEM analysis with the results of physical verification test, in which the real behavior of the bearing element can be observed. The results of the comparison can be used for calibration of the computational model.The article deals with the physical test of steel supporting elements, whose main purpose is obtaining of material, geometry and strength characteristics of the fillet welds. The main aim was defining of tested samples numerical models for using FEM analysis and for the commercial software ANSYS. The pressure test was performed during the experiment, wherein the total load value and the corresponding deformation of the specimens under the load was monitored. The measurements were carried out for a more detailed analysis of stresses and deformations in welds samples using a strain-gauge and a Q100 laser device for measuring the 3D deformation and infrared thermographic non-destructive testing.Obtained data were used for the calibration of numerical models of test samples and they are necessary for further strain analysis of steel supporting elements.

      PubDate: 2018-02-26T01:24:18Z
      DOI: 10.1016/j.advengsoft.2017.03.013
      Issue No: Vol. 117 (2018)
       
  • Running high resolution coastal models in forecast systems: Moving from
           workstations and HPC cluster to cloud resources
    • Authors: João Rogeiro; Marta Rodrigues; Alberto Azevedo; Anabela Oliveira; João Paulo Martins; Mário David; João Pina; Nuno Dias; Jorge Gomes
      Pages: 70 - 79
      Abstract: Publication date: March 2018
      Source:Advances in Engineering Software, Volume 117
      Author(s): João Rogeiro, Marta Rodrigues, Alberto Azevedo, Anabela Oliveira, João Paulo Martins, Mário David, João Pina, Nuno Dias, Jorge Gomes
      Computational forecast systems (CFS) are essential modelling tools for coastal management by providing water dynamics predictions. Nowadays CFS are processed in dedicated workstations, fulfilling quality control through automatic comparison with field data. Recently, CFS has been successfully ported to High Performance Computing (HPC) resources, maintained by highly-specialized staff in these complex environments. The need to increase the available resources for more demanding applications and to enhance the portability for use in non-scientific institutions has promoted the search for more flexible and user-friendly approaches. The scalability and flexibility of cloud resources, with dedicated services for facilitating their use, makes them an attractive option. Herein, the performance of CFS using ECO-SELFE MPI-based model is assessed and compared for the first time in multiple environments, including local workstations, an HPC cluster and a pilot cloud. The analysis is conducted in a range of resources from the physical core count available at the smaller resources to the optimal number of processes, using cloud and HPC cluster resources. Results for the smaller, common physical resources show that the cloud is an attractive option for CFS operation. As the optimal number of processes for the use case is at the limit of the workstations common pool, an analysis was also performed using HPC cluster nodes and federated MPI resources. Results show that the cloud remains an attractive option for CFS. This conclusion is valid both for the use of a single host or through federated hosts, providing that efficient communication infrastructure (such as SRIOV) is available.

      PubDate: 2018-02-26T01:24:18Z
      DOI: 10.1016/j.advengsoft.2017.04.002
      Issue No: Vol. 117 (2018)
       
  • Nonlinear analysis of a building surmounted by a reinforced concrete water
           tank under hydrostatic load
    • Authors: Lamia Ait L'Hadj; Hocine Hammoum; Karima Bouzelha
      Pages: 80 - 88
      Abstract: Publication date: March 2018
      Source:Advances in Engineering Software, Volume 117
      Author(s): Lamia Ait L'Hadj, Hocine Hammoum, Karima Bouzelha
      This work presents a methodology for assessing the damage level of an existing structure under seismic action. First, the seismic demand is introduced by the response spectrum provided by the seismic code, and then the nonlinear static equivalent analysis is performed by structural finite element software to obtain the capacity curve. The evaluated performance point according to the pushover analysis is positioned in European macroseismic scale in order to deduce the damage domain of the structure. The effectiveness of this proposed method is tested successfully for a real case. As a practical application, we analyse a highly complex structure which is an apartment building in Algiers surmounted by a reinforced concrete water tank with a container capacity of 1000 m3. It is complex in its design and analysis, and complex also by its behaviour under earthquake effect. Since being commissioned in 1962, this structure has been subjected to several earthquakes, but the one that hit Boumerdes town on 2003, was fatal for it. The proposed approach classifies the studied structure in the third domain; which describes a very important state of damage. This work fits into a practical environment of the engineering by combining analysis software with design codes and by the applicative character of the proposed approach.

      PubDate: 2018-02-26T01:24:18Z
      DOI: 10.1016/j.advengsoft.2017.04.005
      Issue No: Vol. 117 (2018)
       
  • An iterative method for the linearization of nonlinear failure criteria
    • Authors: S.K. Sharan
      Pages: 89 - 94
      Abstract: Publication date: March 2018
      Source:Advances in Engineering Software, Volume 117
      Author(s): S.K. Sharan
      Linearization of a nonlinear failure criterion may be required if a software incorporating the nonlinear failure criterion is not readily available or if an additional computational difficulty is encountered due to the nonlinearity of the failure criterion. In this paper, a novel method is proposed for the linearization of nonlinear failure criteria. The proposed method is based on an iterative procedure and the least-squares regression is used for the linearization. The material is assumed to be elastic-perfectly plastic. By conducting analytical and finite element analyses of stresses and displacements around underground openings in rock mass governed by the generalized Hoek–Brown failure criterion, it is shown that the proposed method is convergent, efficient and effective.

      PubDate: 2018-02-26T01:24:18Z
      DOI: 10.1016/j.advengsoft.2017.04.008
      Issue No: Vol. 117 (2018)
       
  • Computing permissible design spaces under consideration of functional
           responses
    • Authors: W. Graf; M. Götz; M. Kaliske
      Pages: 95 - 106
      Abstract: Publication date: March 2018
      Source:Advances in Engineering Software, Volume 117
      Author(s): W. Graf, M. Götz, M. Kaliske
      The design of structures is one of the major tasks for engineers. The objectives of numerical design – computing robust and reliable structures – can be realized by means of analyzing different variants, application of optimization tasks, or solving inverse problems. The method of choice depends on the objective of design, the problem and available data/resources. This contribution introduces an application oriented procedure for the solution of an inverse problem, on the basis of existing data. This data consists of design vectors and related responses. This contribution is focused on functional responses. With this procedure independent areas of permissible designs can identified. These areas are approximatively described by hyperrectangles, which are multi-dimensional boxes. The procedure uses various algorithms within the context of data mining. The relevant methods will be discussed shortly. The proposed field of application is the detection permissible design spaces in early design stages. Therefore the applicability of the presented procedure is shown by practical numerical design studies.

      PubDate: 2018-02-26T01:24:18Z
      DOI: 10.1016/j.advengsoft.2017.05.015
      Issue No: Vol. 117 (2018)
       
  • A half-analytical elastic solution for 2D analysis of cracked pavements
    • Authors: H. Nasser; A. Chabot
      Pages: 107 - 122
      Abstract: Publication date: March 2018
      Source:Advances in Engineering Software, Volume 117
      Author(s): H. Nasser, A. Chabot
      This paper presents a half-analytical elastic solution convenient for parametric studies of 2D cracked pavements. The pavement structure is reduced to three elastic and homogeneous equivalent layers resting on a soil. In a similar way than the Pasternak's modelling for concrete pavements, the soil is modelled by one layer, named shear layer, connected to Winkler's springs in order to ensure the transfer of shear stresses between the pavement structure and the springs. The whole four-layer system is modelled using a specific model developed for the analysis of delamination in composite materials. It reduces the problem by one dimension and gives access to regular interface stresses between layers at the edge of vertical cracks allowing the initial debonding analysis. In 2D plane strain conditions, a system of twelve-second order differential equations is written analytically. This system is solved numerically by the finite difference method (Newmark) computed in the free Scilab software.The calculus tool allows analysis of the impact of material characteristics changing, loads and locations of cracks in pavements on the distribution of mechanical fields. The approach with fracture mechanic concepts is well suited for practical use and for some subsequent numerical developments in 3D.

      PubDate: 2018-02-26T01:24:18Z
      DOI: 10.1016/j.advengsoft.2017.06.008
      Issue No: Vol. 117 (2018)
       
  • Euler-Lagrange Computational Fluid Dynamics simulation of a full-scale
           unconfined anaerobic digester for wastewater sludge treatment
    • Authors: D. Dapelo; J. Bridgeman
      Pages: 153 - 169
      Abstract: Publication date: March 2018
      Source:Advances in Engineering Software, Volume 117
      Author(s): D. Dapelo, J. Bridgeman
      For the first time, an Euler-Lagrange model for Computational Fluid Dynamics (CFD) is used to model a full-scale gas-mixed anaerobic digester. The design and operation parameters of a digester from a wastewater treatment works are modelled, and mixing is assessed through a novel, multi-facetted approach consisting of the simultaneous analysis of (i) velocity, shear rate and viscosity flow patterns, (ii) domain characterization following the average shear rate value, and (iii) concentration of a non-diffusive scalar tracer. The influence of sludge’s non-Newtonian behaviour on flow patterns and its consequential impact on mixing quality were discussed for the first time. Recommendations to enhance mixing effectiveness are given: (i) a lower gas mixing input power can be used in the digester modelled within this work without a significant change in mixing quality, and (ii) biogas injection should be periodically switched between different nozzle series placed at different distances from the centre.

      PubDate: 2018-02-26T01:24:18Z
      DOI: 10.1016/j.advengsoft.2017.08.009
      Issue No: Vol. 117 (2018)
       
  • Parallel implementation of hyper-dimensional dynamical particle system on
           CUDA
    • Authors: Jan Mašek; Miroslav Vořechovský
      Abstract: Publication date: Available online 7 April 2018
      Source:Advances in Engineering Software
      Author(s): Jan Mašek, Miroslav Vořechovský
      The presented paper deals with possible approaches to parallel implementation of solution of a hyper-dimensional dynamical particle system. The proposed implementation approaches are generally applicable for similar particle systems of interest in various research and engineering fields. The original motivation for the present work was a simulation of particles that represent a space-filling design to be optimized for further use in design of experiments. Due to the underlying purpose of this particle system, the dimension of the particle system of interest is considered to be entirely arbitrary. Such a hyper-dimensional space is further folded into a periodically repeated domain. The theoretical background of the proposed particle system is provided along with the derivation of equations of motion of the dynamical system. As the complexity of the system is not limited by the number of particles nor the number of dimensions, the possibilities of utilizing the GPGPU platform are more restricted in comparison with today’s fast parallel implementations of common particle systems. Two distinct approaches to parallel implementation are presented, one aiming at a generalized usage of the fast on-chip resources, the other entirely relying on the GPU’s on-board global memory. Despite unambiguous mutual differences in their performance, both parallel implementations deliver major speedup compared to the single-thread CPU solution as well as a better scaling of execution time when increasing both the number of particles and dimensions.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.03.009
       
  • Shape optimization of automotive body frame using an improved genetic
           algorithm optimizer
    • Authors: Huan Qin; Yi Guo; Zijian Liu; Yu Liu; Haolong Zhong
      Abstract: Publication date: Available online 6 April 2018
      Source:Advances in Engineering Software
      Author(s): Huan Qin, Yi Guo, Zijian Liu, Yu Liu, Haolong Zhong
      At conceptual design stage, the cross-sectional shape design of automotive body-in-white (BIW) frame is a critical and intractable technique. This paper presents shape optimization using an improved genetic algorithm (GA) optimizer to promote the development of auto-body. The shape optimization problem is formulated as a mass minimization problem with static stiffness, dynamic eigenfrequency and manufacture constraints. Then the transfer stiffness matrix method (TSMM) proposed in our previous study is adopted for the exact static and dynamic analyses of BIW frame. Additionally, the scale vector method is introduced to remarkably reduce design variables. Especially, an integrated object-oriented GA optimizer, which employs penalty-parameterless approach to handle constraints, is developed to solve constrained single-objective and multi-objective optimization problems. The optimizer is benchmarked on 12 test functions and compared with a variety of current metaheuristic algorithms to demonstrate its validity and effectiveness. Lastly, the optimizer is applied to the solution of BIW shape optimization.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.03.015
       
  • Research on structural optimization method of FRP fishing vessel based on
           artificial bee colony algorithm
    • Authors: Kai Li; Yanyun Yu; Yunlong Wang; Zhenwu Hu
      Abstract: Publication date: Available online 5 April 2018
      Source:Advances in Engineering Software
      Author(s): Kai Li, Yanyun Yu, Yunlong Wang, Zhenwu Hu
      Due to the increase of the operating cost and material cost, weight reduction has attracted much attention among ship designers and ship owners. Ship structure optimization remains a very complicated problem due to the feasible combinations of structural members with different sections are numerous. In the present work, based on artificial bee colony (ABC) algorithm, we propose a structural design optimization method of fiber reinforced plastic (FRP) ship structure. The objective of the proposed optimization method is to minimize the weight of FRP ship structure under a group of constraints. In order to deal with parametric finite element analysis (FEA) of the whole FRP ship structure, the modeling work is simplified by using beam element instead of shell element to simulate top hat stiffener. To evaluate the applicability of the proposed method, it was applied to a problem for finding optimal structure of a 32.98 m FRP fishing vessel. The result shows that the developed program can decrease the structural weight by about 8.31%. Thus, this study will be able to contribute to make energy saving and environment-friendly ship.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.03.011
       
  • An optimization approach for agent-based computational models of
           biological development
    • Authors: Pablo Gonzalez-de-Aledo; Andrey Vladimirov; Marco Manca; Jerry Baugh; Ryo Asai; Marcus Kaiser; Roman Bauer
      Abstract: Publication date: Available online 5 April 2018
      Source:Advances in Engineering Software
      Author(s): Pablo Gonzalez-de-Aledo, Andrey Vladimirov, Marco Manca, Jerry Baugh, Ryo Asai, Marcus Kaiser, Roman Bauer
      Current research in the field of computational biology often involves simulations on high-performance computer clusters. It is crucial that the code of such simulations is efficient and correctly reflects the model specifications. In this paper, we present an optimization strategy for agent-based simulations of biological dynamics using Intel Xeon Phi coprocessors, demonstrated by a prize-winning entry of the “Intel Modern Code Developer Challenge” competition. These optimizations allow simulating various biological mechanisms, in particular the simulation of millions of cells, their proliferation, movements and interactions in 3D space. Overall, our results demonstrate a powerful approach to implement and conduct very detailed and large-scale computational simulations for biological research. We also highlight the main difficulties faced when developing such optimizations, in particular the assessment of the simulation accuracy, the dependencies between different optimization techniques and counter-intuitive effects in the speed of the optimized solution. The overall speedup of 595 ×  shows a good parallel scalability.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.03.010
       
  • Modelling of nitrogen leaching from watersheds with large drained peat
           areas
    • Authors: Anatoli Vassiljev; Katrin Kaur; Ivar Annus
      Abstract: Publication date: Available online 23 March 2018
      Source:Advances in Engineering Software
      Author(s): Anatoli Vassiljev, Katrin Kaur, Ivar Annus
      The SOIL and MACRO models with different versions of SOILN initially developed for small field-scales were used to simulate the water flow and nitrate N concentrations in two watersheds in Estonia that contain large areas of peat soils. Monitoring data show that nitrogen concentrations tend to increase in some rivers even where the human activity is very low. This may be connected to soil self-degradation processes taking place in drained peat soils where it is difficult to use most of the hydrological models. Results show that SOIL, MACRO and SOILN may be successfully applied at the watershed scale to model the water quantity and quality on watersheds with high content of peat soils. The analysis revealed that the nitrate nitrogen level trends depend considerably on the meteorological conditions.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.03.007
       
  • Parallel two-stage algorithms for solving the PageRank problem
    • Authors: Violeta
      Abstract: Publication date: Available online 13 March 2018
      Source:Advances in Engineering Software
      Author(s): Héctor Migallón, Violeta Migallón, José Penadés
      In this work we present parallel algorithms based on the use of two-stage methods for solving the PageRank problem as a linear system. Different parallel versions of these methods are explored and their convergence properties are analyzed. The parallel implementation has been developed using a mixed MPI/OpenMP model to exploit parallelism beyond a single level. In order to investigate and analyze the proposed parallel algorithms, we have used several realistic large datasets. The numerical results show that the proposed algorithms can speed up the time to converge with respect to the parallel Power algorithm and behave better than other well-known techniques.

      PubDate: 2018-04-15T11:40:36Z
       
  • CUDA accelerated implementation of parallel dynamic relaxation
    • Abstract: Publication date: Available online 8 March 2018
      Source:Advances in Engineering Software
      Author(s): P. Iványi
      The dynamic relaxation method has been widely used for the design and analysis of cable-membrane structures. The method iteratively determines a static solution and it has already been parallelized with the MPI environment to speed up the analysis process. This paper discusses a new parallelization approach, which is programmed with the NVIDIA CUDA API and executed on GPU systems. Since a GPU system has a large number of cores and a separate memory from the computer therefore the original dynamic relaxation method has to be reorganized. The paper also discusses the performance measurements of the dynamic relaxation method on GPU systems.

      PubDate: 2018-04-15T11:40:36Z
       
  • Comparative studies of metamodeling and AI-Based techniques in damage
           detection of structures
    • Authors: Ramin Ghiasi; Mohammad Reza Ghasemi; Mohammad Noori
      Abstract: Publication date: Available online 6 March 2018
      Source:Advances in Engineering Software
      Author(s): Ramin Ghiasi, Mohammad Reza Ghasemi, Mohammad Noori
      Despite advances in computer capacity, the enormous computational cost of running complex engineering simulations makes it impractical to rely exclusively on simulation for the purpose of structural health monitoring. To cut down the cost, surrogate models, also known as metamodels, are constructed and then used in place of the actual simulation models. In this study, structural damage detection is performed using two approaches. In both cases ten popular metamodeling techniques including Back-Propagation Neural Networks (BPNN), Least Square Support Vector Machines (LS-SVMs), Adaptive Neural-Fuzzy Inference System (ANFIS), Radial Basis Function Neural network (RBFN), Large Margin Nearest Neighbors (LMNN), Extreme Learning Machine (ELM), Gaussian Process (GP), Multivariate Adaptive Regression Spline (MARS), Random Forests and Kriging are used and the comparative results are presented. In the first approach, by considering dynamic behavior of a structure as input variables, ten metamodels are constructed, trained and tested to detect the location and severity of damage in civil structures. The variation of running time, mean square error (MSE), number of training and testing data, and other indices for measuring the accuracy in the prediction are defined and calculated in order to inspect advantages as well as the shortcomings of each algorithm. The results indicate that Kriging and LS-SVM models have better performance in predicting the location/severity of damage compared with other methods. In the second approach, after locating precisely the eventual damage of a structure using modal strain energy based index (MSEBI), to efficiently reduce the computational cost of model updating during the optimization process of damage severity detection, the MSEBI of structural elements is evaluated using a properly trained surrogate model. The results indicate that after determining the damage location, the proposed solution method for damage severity detection leads to significant reduction of computational time compared to finite element method. Furthermore, engaging colliding bodies optimization algorithm (CBO) by efficient surrogate model of finite element (FE) model, maintains the acceptable accuracy of damage severity detection.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.02.006
       
  • A critical analysis of expected-compliance model in volume-constrained
           robust topology optimization with normally distributed loading directions,
           using a minimax-compliance approach alternatively
    • Abstract: Publication date: Available online 1 March 2018
      Source:Advances in Engineering Software
      Author(s): A. Csébfalvi, J. Lógó
      Uncertainty is an important consideration in topology optimization to produce robust and reliable solutions. There are several possibilities to take into account the uncertainty in the topology optimization of continuum structures. In this paper, we assume that the only source of uncertainty is the variability of the applied load directions. Most models in this area apply parametric statistical tools to describe the directional uncertainty of the applied loads to produce robust structures which are insensitive to the directional uncertainty as much as possible. In the most popular parametric statistical approach the expected-compliance, based on the directional normality assumption, is used as the preferred measure of robustness. We will proof indirectly that this approach is far from the engineering practice and may give hardly interpretable or totally misleading results, which will be demonstrated by two carefully selected counter-examples. The counter-examples validate the fact that the expected-compliance, as a statistical abstraction based on more or less theoretical assumption about normality, not a general applicable measure of robustness. It will be shown, that the non-parametric and really robust volume-constrained worst-load-direction-oriented minimax-compliance model, used in this paper only as a proofing tool in a very simple form, is a viable alternative of the parametric expected-compliance model and its results and its problem solving process as a whole are very close to the engineering thinking. The worst-load-direction-oriented minimax-compliance-model provides expressive, rigorous, generally applicable, and objective information about the robustness. The parametric expected-compliance in itself as the preferred measure of robustness is unable to characterize the compliance variability, in contrast of the minimax approach which can be describe the compliance variability by a robust range-like measure computed very easily as the difference of the maximal- and minimal-compliance on the set of the feasible loading directions.

      PubDate: 2018-04-15T11:40:36Z
       
  • Static load estimation using artificial neural network: Application on a
           wing rib
    • Authors: Samson B. Cooper; Dario DiMaio
      Abstract: Publication date: Available online 7 February 2018
      Source:Advances in Engineering Software
      Author(s): Samson B. Cooper, Dario DiMaio
      This paper presents a novel approach to predicting the static load on a large wing rib in the absence of load cells. A Finite Element model of the wing rib was designed and calibrated using measured data obtained from static experimental test. An Artificial Neural Network (ANN) model was developed to predict the static load applied on the wing rib, this was achieved by using random data and strain values obtained from the static test as input parameters. A number of two layer feed-forward networks were designed and trained in MATLAB using the back-propagation algorithm. The first set of Neural Networks (NN) were trained using random data as inputs, measured strain values were introduced as input into the already trained neural network to access the training algorithm and quantify the accuracy of the static load prediction produced by the trained NN. In addition, a procedure that combines ANN and FE modelling to create a hybrid inverse problem analysis and load monitoring tool is presented. The hybrid approach is based on using trained NN to estimate the applied load from a known FE structural response. Results obtained from this research proves that using an ANN to identify loads is feasible and a well-trained NN shows fast convergence and high degree of accuracy of 92% in the load identification process. Finally, additional trained network results showed that ANN as an inverse problem solver can be used to estimate the load applied on a structure once the load-response relationship has been identified.

      PubDate: 2018-04-15T11:40:36Z
      DOI: 10.1016/j.advengsoft.2018.01.007
       
  • Reliability-based design: Artificial neural networks and double-loop
           reliability-based optimization approaches
    • Authors: Slowik
      Abstract: Publication date: March 2018
      Source:Advances in Engineering Software, Volume 117
      Author(s): D. Lehký, O. Slowik, D. Novák
      Two advanced optimization approaches to solving a reliability-based design problem are presented. The first approach is based on the utilization of an artificial neural network and a small-sample simulation technique. The second approach considers an inverse reliability task as a reliability-based optimization task using a double-loop optimization method based on small-sample simulation. Both techniques utilize Latin hypercube sampling with correlation control. The efficiency of both approaches is tested using three numerical examples of structural design – a cantilever beam, a reinforced concrete slab and a post-tensioned composite bridge. The advantages and disadvantages of the approaches are discussed.

      PubDate: 2018-02-26T01:24:18Z
       
  • Quasi static and dynamic inelastic buckling and failure of folded-plate
           structures by a full-energy finite strip method
    • Authors: D.D.
      Abstract: Publication date: March 2018
      Source:Advances in Engineering Software, Volume 117
      Author(s): D.D. Milašinović, D. Majstorović, R. Vukomanović
      A study on how a mathematical material modeling approach named rheological-dynamical analogy (RDA) can be used to predict the quasi static and dynamic inelastic buckling and failure of structures is presented in this paper. An analysis of the uniformly compressed folded-plate structures, made of isotropic materials, is carried out. Two sources of non-linearity, one involving geometrical non-linearity due to large deflection, and the other involving material non-linearity due to inelastic behavior, are analyzed by implementing a full-energy finite strip method (FSM). The material non-linearity is analyzed using the RDA. A very basic continuum damage model with one damage parameter is implemented in conjunction with a mathematical material modeling approach in order to address stiffness reduction due to inelastic behavior. According to the analogy, a very complicated material non-linear problem in the inelastic range of strains is solved as a simple linear dynamic one. The orthotropic constitutive relations are derived and modulus iterative method for the solution of nonlinear equations is presented.

      PubDate: 2018-02-26T01:24:18Z
       
  • JACK2: An MPI-based communication library with non-blocking
           synchronization for asynchronous iterations
    • Authors: Frédéric Magoulès; Guillaume Gbikpi-Benissan
      Abstract: Publication date: Available online 13 February 2018
      Source:Advances in Engineering Software
      Author(s): Frédéric Magoulès, Guillaume Gbikpi-Benissan
      In this paper, we address the design of a communication library which particularly targets distributed iterative computing, including randomly executed asynchronous iterations. The well-known MPI programming framework is considered, upon which unique generic routines are proposed for both blocking and non-blocking communication modes. This allows for developing unique software applications to experiment both classical and asynchronous iterative methods through the same programming pattern. Convergence detection issues are investigated on pure algorithmic aspects, from which we provide an efficient exact approach to compute global convergence residual norms, by means of non-blocking synchronization. Point-to-point message reception and sending requests are carefully handled in view of producing the least possible delays about transmitted iterative data. Extensive experiments with an existing MPI-based scientific application validate both the proposed MPI-like programming framework and design options to achieve best performances of asynchronous iterative computing.

      PubDate: 2018-02-26T01:24:18Z
      DOI: 10.1016/j.advengsoft.2018.01.009
       
  • A B-spline design model for propeller blades
    • Abstract: Publication date: April 2018
      Source:Advances in Engineering Software, Volume 118
      Author(s): F. Pérez-Arribas, R. Pérez-Fernández
      This work presents a new design methodology for modelling the blades of propellers using B-spline surfaces. Propeller blades are good examples of free form surfaces, designed specifically considering several parameters that control their performance. Traditional tools for surface design in CAD, such as control point manipulation, are not appropriated for blade design, and the designers prefer to work with design parameters that possess a clear aerodynamic / hydrodynamic meaning. This method uses common design parameters for the geometry of propellers and produces a final B-spline surface for the geometry of the blades that can be used for the visualisation, calculations, and construction of the propeller. The method starts with the definition of a 3D grid of points that form the propeller blades based on the 2D definition of a series of cross-sectional profiles at several radial locations. Propeller blades are very thin objects with great changes of curvature, and if standard B-spline techniques are used, they cannot be modelled well under a tolerance unless a large number of control points is used, producing very complex surfaces. The inclination and twist of the blades are given by rake and pitch angles, quite common in the design procedures. The method stresses the fitting of the blade's leading edge which has great effect on the propeller behaviour and geometrically has a small curvature radius in comparison with the rest of the blades.

      PubDate: 2018-02-05T00:15:34Z
       
  • Optimized segmented heat source for the numerical simulation of
           welding-induced deformation in large structures
    • Authors: Haichao Wang; Zhijiang Wang; Pengfei Bai; Shengsun Hu; Yanshen Zhang; Ren Wang
      Pages: 1 - 7
      Abstract: Publication date: March 2018
      Source:Advances in Engineering Software, Volume 117
      Author(s): Haichao Wang, Zhijiang Wang, Pengfei Bai, Shengsun Hu, Yanshen Zhang, Ren Wang
      A segmented heat source is typically used in welding processes with high energy density and high welding speed, such as laser beam welding. In such welding processes, the intense heat source runs through one segment so quickly that the heating processes in each segment could be considered as a segmented heat source with the largest heat flux heating in a short time. It is then possible to use a segmented heat source model to reduce the computation time. In the present work, a feasible and highly efficient optimized segmented heat source, in which cooling time is considered, was proposed to extend its application area. The optimized segmented heat source could be applied to simulate welding processes with various welding speeds and to simulate large structures with high efficiency. The axial strain in welding a pipe with external diameter of 510 mm and wall thickness of 13.5 mm by shielded metal arc welding was measured to verify the accuracy of the proposed heat source. The temperature filed characteristics and the prediction of welding deformation and its distribution were discussed to measure the accuracy and efficiency of the model with the proposed heat source. The model with the optimized segmented heat source predicts the welding deformation with higher accuracy compared to the model with the traditional segmented heat source; however, the efficiency was compromised. Its accuracy is in the range of 10% compared to the model with a double-ellipsoidal heat source, but it is more effective.

      PubDate: 2017-12-26T18:05:57Z
      DOI: 10.1016/j.advengsoft.2017.12.005
      Issue No: Vol. 117 (2017)
       
 
 
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