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  Subjects -> COMPUTER SCIENCE (Total: 1969 journals)
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COMPUTER SCIENCE (1147 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: 11)
Abakós     Open Access   (Followers: 3)
Academy of Information and Management Sciences Journal     Full-text available via subscription   (Followers: 67)
ACM Computing Surveys     Hybrid Journal   (Followers: 23)
ACM Journal on Computing and Cultural Heritage     Hybrid Journal   (Followers: 8)
ACM Journal on Emerging Technologies in Computing Systems     Hybrid Journal   (Followers: 13)
ACM Transactions on Accessible Computing (TACCESS)     Hybrid Journal   (Followers: 4)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 16)
ACM Transactions on Applied Perception (TAP)     Hybrid Journal   (Followers: 6)
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: 11)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 4)
ACM Transactions on Computer Systems (TOCS)     Hybrid Journal   (Followers: 18)
ACM Transactions on Computer-Human Interaction     Hybrid Journal   (Followers: 12)
ACM Transactions on Computing Education (TOCE)     Hybrid Journal   (Followers: 3)
ACM Transactions on Design Automation of Electronic Systems (TODAES)     Hybrid Journal   (Followers: 1)
ACM Transactions on Economics and Computation     Hybrid Journal  
ACM Transactions on Embedded Computing Systems (TECS)     Hybrid Journal   (Followers: 4)
ACM Transactions on Information Systems (TOIS)     Hybrid Journal   (Followers: 19)
ACM Transactions on Intelligent Systems and Technology (TIST)     Hybrid Journal   (Followers: 9)
ACM Transactions on Interactive Intelligent Systems (TiiS)     Hybrid Journal   (Followers: 4)
ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP)     Hybrid Journal   (Followers: 10)
ACM Transactions on Reconfigurable Technology and Systems (TRETS)     Hybrid Journal   (Followers: 7)
ACM Transactions on Sensor Networks (TOSN)     Hybrid Journal   (Followers: 8)
ACM Transactions on Speech and Language Processing (TSLP)     Hybrid Journal   (Followers: 10)
ACM Transactions on Storage     Hybrid Journal  
ACS Applied Materials & Interfaces     Full-text available via subscription   (Followers: 21)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Ad Hoc Networks     Hybrid Journal   (Followers: 11)
Adaptive Behavior     Hybrid Journal   (Followers: 10)
Advanced Engineering Materials     Hybrid Journal   (Followers: 24)
Advanced Science Letters     Full-text available via subscription   (Followers: 5)
Advances in Adaptive Data Analysis     Hybrid Journal   (Followers: 8)
Advances in Artificial Intelligence     Open Access   (Followers: 14)
Advances in Artificial Neural Systems     Open Access   (Followers: 4)
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: 15)
Advances in Computer Science : an International Journal     Open Access   (Followers: 13)
Advances in Computing     Open Access   (Followers: 3)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 53)
Advances in Engineering Software     Hybrid Journal   (Followers: 25)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 9)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 23)
Advances in Human-Computer Interaction     Open Access   (Followers: 19)
Advances in Materials Sciences     Open Access   (Followers: 16)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 35)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Advances in Technology Innovation     Open Access  
AEU - International Journal of Electronics and Communications     Hybrid Journal   (Followers: 8)
African Journal of Information and Communication     Open Access   (Followers: 6)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 4)
Air, Soil & Water Research     Open Access   (Followers: 7)
AIS Transactions on Human-Computer Interaction     Open Access   (Followers: 6)
Algebras and Representation Theory     Hybrid Journal   (Followers: 1)
Algorithms     Open Access   (Followers: 9)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 3)
American Journal of Computational Mathematics     Open Access   (Followers: 4)
American Journal of Information Systems     Open Access   (Followers: 6)
American Journal of Sensor Technology     Open Access   (Followers: 2)
Anais da Academia Brasileira de Ciências     Open Access   (Followers: 2)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 5)
Analysis in Theory and Applications     Hybrid Journal  
Animation Practice, Process & Production     Hybrid Journal   (Followers: 5)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Data Science     Hybrid Journal   (Followers: 8)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 6)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Software Engineering     Hybrid Journal   (Followers: 12)
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: 2)
Applied Artificial Intelligence: An International Journal     Hybrid Journal   (Followers: 13)
Applied Categorical Structures     Hybrid Journal   (Followers: 2)
Applied Clinical Informatics     Hybrid Journal   (Followers: 1)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Computer Systems     Open Access   (Followers: 1)
Applied Informatics     Open Access  
Applied Mathematics and Computation     Hybrid Journal   (Followers: 31)
Applied Medical Informatics     Open Access   (Followers: 9)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Soft Computing     Hybrid Journal   (Followers: 16)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Architectural Theory Review     Hybrid Journal   (Followers: 3)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 4)
Archive of Numerical Software     Open Access  
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Artifact     Hybrid Journal   (Followers: 2)
Artificial Life     Hybrid Journal   (Followers: 5)
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  
Automatic Control and Computer Sciences     Hybrid Journal   (Followers: 3)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Automatica     Hybrid Journal   (Followers: 8)
Automation in Construction     Hybrid Journal   (Followers: 6)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 7)
Basin Research     Hybrid Journal   (Followers: 3)
Behaviour & Information Technology     Hybrid Journal   (Followers: 52)
Bioinformatics     Hybrid Journal   (Followers: 231)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 16)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 31)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 45)
British Journal of Educational Technology     Hybrid Journal   (Followers: 119)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
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: 12)
Catalysis in Industry     Hybrid Journal   (Followers: 1)
CEAS Space Journal     Hybrid Journal  
Cell Communication and Signaling     Open Access   (Followers: 1)
Central European Journal of Computer Science     Hybrid Journal   (Followers: 5)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 15)
ChemSusChem     Hybrid Journal   (Followers: 7)
China Communications     Full-text available via subscription   (Followers: 7)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
CIN Computers Informatics Nursing     Full-text available via subscription   (Followers: 12)
Circuits and Systems     Open Access   (Followers: 13)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
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  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Communication Methods and Measures     Hybrid Journal   (Followers: 11)
Communication Theory     Hybrid Journal   (Followers: 18)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Algebra     Hybrid Journal   (Followers: 3)
Communications in Partial Differential Equations     Hybrid Journal   (Followers: 3)
Communications of the ACM     Full-text available via subscription   (Followers: 47)
Communications of the Association for Information Systems     Open Access   (Followers: 18)
COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering     Hybrid Journal   (Followers: 3)
Complex & Intelligent Systems     Open Access  
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: 9)
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  
Computational Biology and Chemistry     Hybrid Journal   (Followers: 12)
Computational Chemistry     Open Access   (Followers: 2)
Computational Cognitive Science     Open Access   (Followers: 1)
Computational Complexity     Hybrid Journal   (Followers: 4)
Computational Condensed Matter     Open Access  
Computational Ecology and Software     Open Access   (Followers: 8)
Computational Economics     Hybrid Journal   (Followers: 9)
Computational Geosciences     Hybrid Journal   (Followers: 12)
Computational Linguistics     Open Access   (Followers: 23)
Computational Management Science     Hybrid Journal  
Computational Mathematics and Modeling     Hybrid Journal   (Followers: 8)
Computational Mechanics     Hybrid Journal   (Followers: 4)
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: 13)
Computational Statistics & Data Analysis     Hybrid Journal   (Followers: 27)
Computer     Full-text available via subscription   (Followers: 78)
Computer Aided Surgery     Hybrid Journal   (Followers: 3)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Communications     Hybrid Journal   (Followers: 10)
Computer Engineering and Applications Journal     Open Access   (Followers: 5)
Computer Journal     Hybrid Journal   (Followers: 8)
Computer Methods in Applied Mechanics and Engineering     Hybrid Journal   (Followers: 22)
Computer Methods in Biomechanics and Biomedical Engineering     Hybrid Journal   (Followers: 10)
Computer Methods in the Geosciences     Full-text available via subscription   (Followers: 1)
Computer Music Journal     Hybrid Journal   (Followers: 13)
Computer Physics Communications     Hybrid Journal   (Followers: 6)
Computer Science - Research and Development     Hybrid Journal   (Followers: 7)
Computer Science and Engineering     Open Access   (Followers: 17)
Computer Science and Information Technology     Open Access   (Followers: 10)
Computer Science Education     Hybrid Journal   (Followers: 12)
Computer Science Journal     Open Access   (Followers: 20)
Computer Science Master Research     Open Access   (Followers: 9)
Computer Science Review     Hybrid Journal   (Followers: 10)

        1 2 3 4 5 6 | Last

Journal Cover Archive of Applied Mechanics
  [SJR: 0.865]   [H-I: 40]   [4 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0939-1533 - ISSN (Online) 1432-0681
   Published by Springer-Verlag Homepage  [2329 journals]
  • Preface: Modelling and numerical simulations of dynamical systems
    • Authors: Jan Awrejcewicz; Nuno Maia; Jerzy Mrozowski
      Pages: 783 - 784
      PubDate: 2017-05-01
      DOI: 10.1007/s00419-017-1236-y
      Issue No: Vol. 87, No. 5 (2017)
       
  • Dynamics of mechanical systems with two sliding contacts: new facets of
           Painlevé’s paradox
    • Authors: Péter L. Várkonyi
      Pages: 785 - 799
      Abstract: Abstract We investigate the dynamics of finite degree-of-freedom, planar mechanical systems with multiple sliding, unilateral frictional point contacts. A complete classification of systems with 2 sliding contacts is given. The contact-mode-based approach of rigid body mechanics is combined with linear stability analysis using a compliant contact model to determine the feasibility and the stability of every possible contact mode in each class. Special forms of non-stationary contact dynamics including “impact without collision” and “reverse chattering” are also investigated. Many types of solution inconsistency and indeterminacy are identified and new phenomena related to Painlevé’s non-existence and non-uniqueness paradoxes are discovered. Among other results, we show that the non-existence paradox is not fully resolvable by considering impulsive contact forces. These findings contribute to a growing body of evidence that rigid body mechanics cannot be developed into a complete and self-consistent theory in the presence of contacts and friction.
      PubDate: 2017-05-01
      DOI: 10.1007/s00419-016-1165-1
      Issue No: Vol. 87, No. 5 (2017)
       
  • Diagnostics of the railway friction disc brake based on the analysis of
           the vibration signals in terms of resonant frequency
    • Authors: Wojciech Sawczuk; Grzegorz M. Szymański
      Pages: 801 - 815
      Abstract: Abstract Increasing the speed of trains forces the application of a greater braking power, i.e. the capability of the brake system of rapidly absorbing and dispersing the stored heat energy. The instability of operation results from the occurrence of vibrations on the friction component, which affects the efficiency of the braking process. In practice, it means that when braking, the vehicle variable friction resistance may lead to an uneven braking process. The effects of such changes can be manifested in the form of vibrations with high input amplitude. The vibrations generated by the working components are distributed throughout the vehicle, which also adversely affects the driving comfort. The purpose of this paper is to determine the resonant frequencies of selected components of the railway disc brake. This paper presents a method of assessing the thickness of the brake pads of a railway disc brake based on the results of parameterization of the time-frequency map a(t, f) of vibrations generated by the brake components. Methods of time-frequency analysis were suggested as a tool of time-frequency selection of the vibration signal. The authors described an algorithm of the method and presented an example illustrating the application of the synchronously averaged short-time Fourier transform for the extraction of the signal components related to the braking process. As a result of parameterization of the map a(t, f) signal parameters, values covariant with the thickness of the disc brake were obtained.
      PubDate: 2017-05-01
      DOI: 10.1007/s00419-016-1202-0
      Issue No: Vol. 87, No. 5 (2017)
       
  • Application of a special class of smooth models of the resultant friction
           force and moment occurring on a circular contact area
    • Authors: Grzegorz Kudra; Jan Awrejcewicz
      Pages: 817 - 828
      Abstract: Abstract Some special cases of a larger class of smooth models of the resultant friction force occurring on a planar contact area are developed and presented. These models are constructed under assumptions of classical Coulomb’s law of friction on each element of contact and instantaneous transition between two modes: fully developed sliding and rigid stick state without local slips and deformations of the contact area. They are able to model cases of different values of static and kinetic friction factors. The considered models are very effective tools for fast and reliable numerical simulations of mechanical systems with frictional contacts. They are applied in modelling and numerical analysis of a special kind of mechanical system, i.e. a kind of a pendulum with special frictional driving. The rotational joint of the pendulum is elastically suspended in the motion plane. The pendulum is driven by circular frictional contact with a rotating disk. Examples of self-excited bifurcation and chaotic dynamics as well as stick–slip behaviour of the pendulum are presented.
      PubDate: 2017-05-01
      DOI: 10.1007/s00419-016-1182-0
      Issue No: Vol. 87, No. 5 (2017)
       
  • On dynamics of a rigid body on a moving rough plane
    • Authors: Yury Selyutskiy; Rinaldo Garziera; Luca Collini
      Pages: 829 - 839
      Abstract: Abstract One of the most destructive effects of earthquakes upon buildings and other constructions is due to horizontal displacement of the ground. This paper proposes a simplified approach to describe behavior of tower-like structures in such conditions. For this aim, a plane-parallel motion of a rigid body over horizontal plane with dry friction is considered. It is assumed that the plane performs harmonic oscillations in horizontal direction. In order to describe collisions between the body and the supporting plane, Routh hypothesis is used. Influence of body aspect ratio and characteristics of the supporting plane acceleration on the behavior of the body is studied.
      PubDate: 2017-05-01
      DOI: 10.1007/s00419-016-1214-9
      Issue No: Vol. 87, No. 5 (2017)
       
  • Motion of double pendulum colliding with an obstacle of rough surface
    • Authors: Grażyna Sypniewska-Kamińska; Roman Starosta; Jan Awrejcewicz
      Pages: 841 - 852
      Abstract: Abstract The externally excited and damped vibration of the double pendulum in the vertical plane are considered. The pendulum can collide many times during the motion with a motionless obstacle having the rough surface. The double pendulum colliding with this object has been modeled as a piecewise smooth system constrained by the unilateral constraint. In the relatively long time between the collisions, the differential equations govern the motion of the pendulum. When the contact with the obstacle appears, the pendulum exhibits a discontinuous behavior. An important element of the solving algorithm is aimed on the continuous tracking of the position of the pendulum in order to detect the collision with the unilateral constraints and to determine the state vector of the pendulum at the impact time instant. A single collision is described by the Euler’s laws of motion in the integral form. The equations are supplemented by the Poisson’s hypothesis and Coulomb’s law of friction. The friction law is formulated for the instantaneous values of the reaction forces. The values of their impulses depend on the existence of a slip between the contacting bodies. Therefore, the Coulomb law cannot be generalized for the linear impulses of the forces in a simple way. We have applied the Routh method in order to solve the problem. The method has a simple geometrical interpretation in the impulse space. The angular velocities of both pendulum parts as well as the reaction forces at the joints of the system, which change in stepwise manner, have been presented in the paper.
      PubDate: 2017-05-01
      DOI: 10.1007/s00419-017-1230-4
      Issue No: Vol. 87, No. 5 (2017)
       
  • Dynamic analysis of a spherical mobile robot based on a tensegrity
           structure with two curved compressed members
    • Authors: Valter Böhm; Tobias Kaufhold; Igor Zeidis; Klaus Zimmermann
      Pages: 853 - 864
      Abstract: Abstract The use of mechanically compliant tensegrity structures in mobile robotics is an attractive research topic. The mechanical properties and therefore the locomotion performance of mobile robots based on these structures can be adjusted reversibly during locomotion. In the present work, a rolling mobile robot, based on a simple tensegrity structure, consisting of two rigid disconnected curved members connected to a continuous net of eight prestressed tensioned members with pronounced elasticity, is considered. Pure rolling uniaxial locomotion and also planar locomotion can be realized with small control effort, induced by the movement of two internal masses. After kinematic considerations, the nonlinear equations of motion are derived and transient dynamic analyses are performed, to study the system behavior. Also the dependency of the rolling movement behavior on structural and actuation parameters is discussed. The uniaxial and planar locomotion performance of the system are verified experimentally.
      PubDate: 2017-05-01
      DOI: 10.1007/s00419-016-1183-z
      Issue No: Vol. 87, No. 5 (2017)
       
  • Cross-checking asymptotics and numerics in the hardening/softening
           behaviour of Timoshenko beams with axial end spring and variable
           slenderness
    • Authors: F. Clementi; S. Lenci; G. Rega
      Pages: 865 - 880
      Abstract: Abstract Two approximate solutions for the nonlinear free oscillations of a planar Timoshenko beam are compared to each other. The beam has an axial spring that permits to consider different boundary conditions, from axially free (which has a softening nonlinear behaviour) to perfectly axially restrained (which has a hardening nonlinear behaviour). The first approximation is analytical and is obtained by the asymptotic development method, while the second is numerical and is obtained by the finite element method. The comparison is made in terms of backbone curves describing the dependence of the (nonlinear) frequency on the oscillation amplitude. Very good agreement is found, for both slender and thick beams, and for varying stiffness of the end spring. This is a cross-check verification of the reliability of both approximate solutions.
      PubDate: 2017-05-01
      DOI: 10.1007/s00419-016-1159-z
      Issue No: Vol. 87, No. 5 (2017)
       
  • Transverse vibrations of a beam under an axial load: minimal model of a
           triangular frame
    • Authors: Paweł Fritzkowski
      Pages: 881 - 892
      Abstract: Abstract The paper is devoted to transverse in-plane vibrations of a beam which is a part of a symmetrical triangular frame. A mathematical model based on the Hamilton principle, formulated for large deflections of the beam subjected to dynamic axial excitation, is presented. An approximate nonlinear ordinary differential equation for the vibration amplitude is derived by means of the Galerkin method. Dynamics of the system is studied numerically for the two cases: harmonic and pulsating load. Various values of the model parameters, including the excitation amplitude and frequency, are considered. The amplitude is taken to be below or above the static critical load. The regions of stable and unstable solutions are determined in parameter planes by evaluation of the maximal Lyapunov exponent. The results are compared to the case of the abbreviated (linear) dynamical system. The stable and unstable beam responses are analysed and classified.
      PubDate: 2017-05-01
      DOI: 10.1007/s00419-016-1156-2
      Issue No: Vol. 87, No. 5 (2017)
       
  • Optimal control of a plan asymmetric structure using magnetorheological
           dampers
    • Authors: Manuel Braz-César; Rui Barros
      Pages: 893 - 904
      Abstract: Abstract Although building structures can be perceived as a combination of primary frames in two orthogonal directions, they are three-dimensional systems that usually present a very complex dynamic behavior due to irregular geometric configurations, in particular due to plant stiffness or mass eccentricities. This asymmetric geometry results in coupled lateral–torsional motion produced by wind and seismic loading with consequences in the design of lateral and corner columns. A considerable amount of research effort has been devoted to develop structural control systems to reduce the effects of plan asymmetries and to improve the dynamic behavior of these buildings. This paper presents a numerical analysis of a semi-active control system with MR dampers designed to reduce lateral–torsional responses of a plan asymmetric building structure excited by El Centro NS earthquake ground motion. A parametric study comprising passive and semi-active control modes is given to demonstrate the effectiveness of the proposed control system with respect to uncontrolled case. The numerical results prove the efficiency of the semi-active control system and its potential use in mitigating coupled lateral–torsional structural responses.
      PubDate: 2017-05-01
      DOI: 10.1007/s00419-016-1191-z
      Issue No: Vol. 87, No. 5 (2017)
       
  • Sensitivity or Bayesian model updating: a comparison of techniques using
           the DLR AIRMOD test data
    • Authors: Edoardo Patelli; Yves Govers; Matteo Broggi; Herbert Martins Gomes; Michael Link; John E. Mottershead
      Pages: 905 - 925
      Abstract: Abstract Deterministic model updating is now a mature technology widely applied to large-scale industrial structures. It is concerned with the calibration of the parameters of a single model based on one set of test data. It is, of course, well known that different analysts produce different finite element models, make different physics-based assumptions, and parameterize their models differently. Also, tests carried out on the same structure, by different operatives, at different times, under different ambient conditions produce different results. There is no unique model and no unique data. Therefore, model updating needs to take account of modeling and test-data variability. Much emphasis is now placed on what has become known as stochastic model updating where data are available from multiple nominally identical test structures. In this paper two currently prominent stochastic model updating techniques (sensitivity-based updating and Bayesian model updating) are described and applied to the DLR AIRMOD structure.
      PubDate: 2017-05-01
      DOI: 10.1007/s00419-017-1233-1
      Issue No: Vol. 87, No. 5 (2017)
       
  • Study of the interaction of matrix crack with inclusions of different
           shapes using the method of caustic
    • Authors: Guoqi Zhao; Wenfeng Hao; Xixuan Sheng; Yin Luo; Guangping Guo
      Abstract: Abstract In this study, the interactions of matrix crack with inclusions of different shapes were investigated using the method of caustic. First, the specimens with inclusions of different shapes were prepared, where glass was used as inclusion and epoxy was used as matrix. Then, caustic experiments were conducted, and the typical caustic spots at the crack tip with varied distances from three different shapes of inclusions were obtained. Ultimately, the stress intensity factors of the cracks shielded by different shapes of inclusions were extracted from the caustic spots, and finite element simulations were conducted to verify the experimental results using the ABAQUS software. The results show that the stress intensity factors measured by the caustic method are in good agreement with the finite element simulation results.
      PubDate: 2017-05-25
      DOI: 10.1007/s00419-017-1261-x
       
  • A feasible symmetric state of initial force design for cable-strut
           structures
    • Authors: Jinyu Zhou; Wujun Chen; Bing Zhao; Shilin Dong
      Abstract: Abstract For a structure with given shape, to acquire feasible pre-stress states without changing its predefined shape is the main purpose of force finding as a crucial step in structural designs, since mechanical behaviors of cable-strut structures are highly sensitive to their pre-tensioning levels. One of practical ways to initial force designs is double singular value decomposition (DSVD), the essence of which is visual inspections of symmetry properties that could be arbitrary and time consuming due to its manual grouping. To reduce the iteration times of finding a proper group division, a grouping scheme was developed by utilizing the distributed static indeterminacy as a symmetry indicator that represents both geometric and stiffness symmetry. The existing DSVD method was subsequently modified using the proposed scheme that could provide an initial group classification being helpful to decrease the undesirable numbers of pre-stress states. Finally, two examples were investigated to verify the validity and accuracy of the modified method, and then it was applied in an enormous stadium with saddle-shaped roof structure showing good agreement with results obtained by a conventional approach.
      PubDate: 2017-05-15
      DOI: 10.1007/s00419-017-1257-6
       
  • Higher-order approximate analytical solutions to nonlinear oscillatory
           systems arising in engineering problems
    • Authors: Mostafa Mohammadian; Mehdi Akbarzade
      Abstract: Abstract In the current paper, a powerful approximate analytical approach namely the global residue harmonic balance method (GRHBM) is proposed for obtaining higher-order approximate frequency and periodic solution of nonlinear conservative oscillatory systems arising in engineering problems. The proposed method has a main difference with other traditional harmonic balance methods such that the residual errors obtained in pervious order approximation are used in the present one. Comparison of the obtained results with the exact and numerical solution as well as well-known analytical methods such as Hamiltonian approach, Max–Min approach, variational approach, and He’s amplitude–frequency formulation reveals the correctness and usefulness of the GRHBM. It is shown that the results are valid for different values of system parameters and both small and large amplitudes. Hence, the method can be easily applied to other strongly nonlinear conservative oscillatory systems. Furthermore, using the obtained analytical expressions, the effect of amplitude and system parameters on nonlinear frequency is studied.
      PubDate: 2017-05-10
      DOI: 10.1007/s00419-017-1252-y
       
  • Stationary dynamics of a chain fountain
    • Authors: Friedrich Pfeiffer; Johannes Mayet
      Abstract: Abstract Chain fountains are known since long time, and many efforts have been taken to model and to explain the dynamics of such a chain fountain. A chain consists of many small elements starting from an inertial container, forms this specific arc and comes to an inertial position again after a rather long vertical distance. As the chain elements are all connected by a bearing-type structure, they all have to move with the same velocity v. In the following we shall consider only the stationary case and not the evolution from a state of rest to the fountain with velocity v. Most models known use the idea of a continuous model. In the following we shall apply multibody theory in addition by modeling each bead with its connections separately. Results confirm the approach.
      PubDate: 2017-05-10
      DOI: 10.1007/s00419-017-1260-y
       
  • A modified algorithm of linear matching method for limit analysis
    • Authors: Jun-Hyok Ri; Hyon-Sik Hong
      Abstract: Abstract Linear matching method has been widely used for the numerical analysis of limit and shakedown. It has been proved theoretically that linear matching method could offer the monotonically reducing sequence of upper bound. Nevertheless, it still remains open whether linear matching method can obtain the conversed and reliable lower bound or not. Thus, an elastic compensation method is used generally for the evaluation of lower bound, but limit analysis using linear matching method and elastic compensation method needs double iterative computations. Moreover, the convergence can be checked only after the computation is finished because linear matching method and elastic compensation method cannot be performed simultaneously. From this, we propose a simple method in order to improve the numerical solution of lower bound by linear matching method. The Young’s modulus varying spatially is determined in every iteration such that not only the stress state lies on the yielding surface but also the strain state does not exceed a certain value of reference strain, leading to the evaluation of lower bound based on the strain state but not the stress one. The proposed method can improve the numerical solution of lower bound by linear matching method without any affection on the upper bound. ANSYS UserMat is used for implementing the current method. The limit analysis is performed like the general elastic finite element analysis in ANSYS. Some numerical examples are considered in order to confirm the effectiveness of proposed approach. Numerical examples showed the validity and improvement of numerical accuracy of our approach. It should be mentioned that our approach can predict the lower bound and upper one simultaneously within the framework of only linear matching method without using the elastic compensation method.
      PubDate: 2017-05-08
      DOI: 10.1007/s00419-017-1258-5
       
  • Identifiability of material parameters in solid mechanics
    • Authors: Stefan Hartmann; Rose Rogin Gilbert
      Abstract: Abstract Material parameter identification using constitutive models of elasticity, viscoelasticity, rate-independent plasticity and viscoplasticity has a long history with regard to homogeneous and inhomogeneous deformations. For example, uniaxial tensile tests, pure shear tests, torsion experiments of thin-walled tubes or biaxial tensile tests are used to obtain the material parameters by solving the inverse problem. Frequently, the parameters are determined by numerical optimization tools. In this paper, we investigate some very basic single- and two-layered examples regarding identifiability, because these tests are the basis for more complex geometrical and physical nonlinear problems. These simple examples are the uniaxial tensile/compression case, biaxial tensile tests of a cruciform specimen, torsion of a thin-walled tube, a thick-walled tube under internal pressure and the indentation test. For the thick-walled tube under internal and external pressure with an axial pre-strain with several layers, an analytical solution is provided directly suitable for programming. The aim is to get an understanding whether some problems lead to non-identifiable parameters.
      PubDate: 2017-05-08
      DOI: 10.1007/s00419-017-1259-4
       
  • Analytic solution for torsion of thin-walled laminated composite beams of
           symmetrical open cross sections with influence of shear
    • Authors: Marko Vukasović; Radoslav Pavazza; Frane Vlak
      Abstract: Abstract An approximate analytic solution for torsion of thin-walled laminated composite beams of symmetrical open cross sections with influence of shear is presented. The solution based on the classical Vlasov’s thin-walled beam theory is modified for thin-walled laminated composite beams with orthotropic and symmetrical lay-up. It is shown that the beam subjected to torsion with influence of shear, caused by couples in the cross section planes, is also subjected to bending due to shear in the plane orthogonal to the plane of symmetry. If the cross section has two axes of symmetry, the beam will be subjected only to torsion with influence of shear. The expressions for the displacements and normal stresses are derived in closed analytic form. The material influence on shear is defined by factor that depends on the fibre orientations. Simply supported and clamped beams subjected to distributed couples are considered. Illustrative examples are provided, and the results for the displacements and stresses show very good agreement between analytical ones and numerically obtained results utilizing three-dimensional shell finite elements.
      PubDate: 2017-05-02
      DOI: 10.1007/s00419-017-1256-7
       
  • Stress–displacement intensity factors for cracks in anisotropic
           media
    • Authors: Alla V. Ilyashenko; Sergey V. Kuznetsov
      Abstract: Abstract For a plane crack of arbitrary loading in a medium with arbitrary elastic anisotropy analytic expressions are derived allowing computing stress intensity factors by the corresponding displacement intensity factors. The relation between both intensity factors is derived for media with arbitrary elastic anisotropy. Comparison with the expressions for a plane crack in isotropic medium is outlined.
      PubDate: 2017-04-26
      DOI: 10.1007/s00419-017-1255-8
       
  • Bifurcation analysis of a rigid-rotor squeeze film damper system with
           unsymmetrical stiffness supports
    • Authors: Huizheng Chen; Lei Hou; Yushu Chen
      Abstract: Abstract This paper is focused on the relationship between rigid body translation and rigid body precession in a squeeze film damper–rigid-rotor system with unsymmetrical stiffness supports. Two cases are considered: the precession motion non-resonance and internal resonance when translation motion occur primary resonant. In the first case, the amplitudes of translation and precession can be connected with an integration parameter about rotor parameters such as geometric size, stiffness, and mass. Some combination of system parameters will make the amplitudes of precession motion reach the same magnitude of the amplitudes of translation motion, so this integration parameter become an index to reflect the precessional motion degree, it is can be used to judge the feasibility of neglecting processional motion and simplifying asymmetry rotor as reasonable symmetry model. In the second case, the translation motion and precessional motion are strongly coupled, the vibration energy transfer between two kind of motion and the system occur internal resonant, which is possible appear in the rotor with cantilever disk. Each of case may appear nonlinear phenomenon, which is closely related with system parameters. The bifurcation analysis by using singularity methods is carried out to delimit the range of applicative operation parameters to avoid harmful phenomenon in unsymmetrical rotor system. The results of this paper provide a theoretical foundation for the convenient model simplification judgment and parameters optimization of the squeeze film damper-unsymmetrical rotor systems.
      PubDate: 2017-04-26
      DOI: 10.1007/s00419-017-1254-9
       
 
 
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