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  Subjects -> ENGINEERING (Total: 2270 journals)
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ENGINEERING (1199 journals)            First | 1 2 3 4 5 6 | Last

Showing 1001 - 1200 of 1205 Journals sorted alphabetically
Progress in Agricultural Engineering Sciences     Full-text available via subscription  
Progress in Computational Fluid Dynamics, An International Journal     Hybrid Journal   (Followers: 7)
Progress in Energy and Combustion Science     Full-text available via subscription   (Followers: 10)
Progress in Nanotechnology and Nanomaterials     Open Access   (Followers: 4)
Progress in Photovoltaics: Research & Applications     Hybrid Journal   (Followers: 6)
Progress in Polymer Science     Full-text available via subscription   (Followers: 32)
Propellants, Explosives, Pyrotechnics     Hybrid Journal   (Followers: 289)
Propulsion and Power Research     Open Access   (Followers: 25)
Purinergic Signalling     Hybrid Journal   (Followers: 1)
Quaderns d’Història de l’Enginyeria     Open Access  
Quality and Reliability Engineering International     Hybrid Journal   (Followers: 14)
Quality Engineering     Hybrid Journal   (Followers: 9)
Radiochimica Acta     Hybrid Journal   (Followers: 5)
Rapid Prototyping Journal     Hybrid Journal   (Followers: 4)
Rare Metals     Hybrid Journal  
Reactive and Functional Polymers     Hybrid Journal   (Followers: 5)
Recent Patents on Engineering     Full-text available via subscription   (Followers: 3)
Recent Patents on Nanotechnology     Full-text available via subscription   (Followers: 3)
Recherche Transports Sécurité     Hybrid Journal   (Followers: 1)
Redes de Ingeniería     Open Access  
Regional Maritime University Journal     Full-text available via subscription   (Followers: 2)
Regular and Chaotic Dynamics     Hybrid Journal  
Rem : Revista Escola de Minas     Open Access   (Followers: 1)
Remote Sensing     Open Access   (Followers: 38)
Remote Sensing Letters     Hybrid Journal   (Followers: 36)
Requirements Engineering     Hybrid Journal   (Followers: 3)
Research Ideas and Outcomes     Open Access  
Research in Engineering Design     Hybrid Journal   (Followers: 11)
Research Journal of Nanoscience and Nanotechnology     Open Access   (Followers: 20)
Research Works of Air Force Institute of Technology     Open Access   (Followers: 1)
Resonance     Hybrid Journal   (Followers: 28)
Reviews in Advanced Sciences and Engineering     Partially Free   (Followers: 2)
Revista AIDIS de Ingeniería y Ciencias Ambientales. Investigación, desarrollo y práctica     Open Access  
Revista Brasileira de Engenharia Agrícola e Ambiental     Open Access   (Followers: 1)
Revista Ciencias e Ingeniería al Día     Open Access  
Revista CINTEX     Open Access   (Followers: 1)
Revista de Engenharia da Universidade Católica de Petrópolis     Open Access  
Revista de Ingeniería     Open Access  
Revista de Ingenieria Sismica     Open Access  
Revista de Investigación, Desarrollo e Innovación     Open Access  
Revista EIA     Open Access   (Followers: 1)
Revista Facultad de Ingeniería     Open Access   (Followers: 1)
Revista Facultad de Ingenieria - Universidad de Tarapaca     Open Access   (Followers: 1)
Revista Facultad de Ingeniería Universidad de Antioquia     Open Access   (Followers: 1)
Revista Fatec Zona Sul : REFAS     Open Access  
Revista Iberoamericana de Automática e Informática Industrial RIAI     Open Access  
Revista Informador Técnico     Open Access   (Followers: 1)
Revista Ingenieria de Construcción     Open Access   (Followers: 1)
Revista Internacional de Métodos Numéricos para Cálculo y Diseño en Ingeniería     Open Access   (Followers: 1)
Revista Logos Ciencia & Tecnología     Open Access   (Followers: 1)
Revue de Métallurgie     Full-text available via subscription  
Russian Engineering Research     Hybrid Journal  
Russian Journal of Non-Ferrous Metals     Hybrid Journal   (Followers: 22)
Russian Microelectronics     Hybrid Journal   (Followers: 1)
Sadhana     Open Access   (Followers: 8)
Safety Science     Hybrid Journal   (Followers: 30)
Scholedge International Journal of Multidisciplinary & Allied Studies     Open Access   (Followers: 3)
Science & Technique     Open Access  
Science and Education : Scientific Publication of BMSTU     Open Access  
Science and Engineering Ethics     Hybrid Journal   (Followers: 9)
Science and Technology     Open Access   (Followers: 2)
Science China Technological Sciences     Hybrid Journal  
Science Journal of Volgograd State University. Technology and innovations     Open Access  
Science Progress     Full-text available via subscription   (Followers: 2)
Scientia cum Industria     Open Access  
Scientific Drilling     Open Access  
Scientific Journal of Control Engineering     Open Access   (Followers: 1)
Sealing Technology     Full-text available via subscription   (Followers: 1)
Securitas Vialis     Hybrid Journal  
Security and Communication Networks     Hybrid Journal   (Followers: 3)
Selcuk University Journal of Engineering, Science and Technology     Open Access  
Selected Topics in Applied Earth Observations and Remote Sensing, IEEE Journal of     Hybrid Journal   (Followers: 48)
Semiconductors     Hybrid Journal  
Semiconductors and Semimetals     Full-text available via subscription   (Followers: 1)
Sensing and Imaging : An International Journal     Hybrid Journal   (Followers: 2)
Sensor Letters     Full-text available via subscription   (Followers: 2)
Sensors     Open Access   (Followers: 15)
Separation and Purification Technology     Hybrid Journal   (Followers: 9)
Services Computing, IEEE Transactions on     Hybrid Journal   (Followers: 5)
Shock and Vibration     Hybrid Journal   (Followers: 9)
SIAM Journal on Applied Dynamical Systems     Hybrid Journal   (Followers: 2)
SIAM Journal on Mathematical Analysis     Hybrid Journal   (Followers: 3)
SIAM Journal on Matrix Analysis and Applications     Hybrid Journal   (Followers: 1)
SIAM Journal on Numerical Analysis     Hybrid Journal   (Followers: 4)
SIAM Journal on Optimization     Hybrid Journal   (Followers: 8)
SIAM Review     Hybrid Journal   (Followers: 6)
SILICON     Hybrid Journal  
Sistemas & Telemática     Open Access   (Followers: 2)
Sleep and Biological Rhythms     Hybrid Journal   (Followers: 6)
Small     Hybrid Journal   (Followers: 11)
Smart Grid     Open Access  
Soft Computing     Hybrid Journal   (Followers: 8)
Software Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 57)
Soil Dynamics and Earthquake Engineering     Hybrid Journal   (Followers: 14)
Soldagem & Inspeção     Open Access  
Solid-State Circuits Magazine, IEEE     Hybrid Journal   (Followers: 10)
SourceOCDE Developpement urbain, rural et regional     Full-text available via subscription   (Followers: 1)
SourceOCDE Energie     Full-text available via subscription  
SourceOECD Energy     Full-text available via subscription  
SourceOECD Science and Technology Statistics - SourceOCDE Base de donnees des sciences et de la technologie     Full-text available via subscription  
SourceOECD Transport     Full-text available via subscription   (Followers: 3)
SourceOECD Urban, Rural and Regional Development     Full-text available via subscription   (Followers: 1)
South African Computer Journal     Full-text available via subscription  
South African Journal of Agricultural Extension     Open Access   (Followers: 4)
South African Journal of Science     Open Access   (Followers: 2)
Sports Engineering     Hybrid Journal   (Followers: 2)
Stahlbau     Hybrid Journal   (Followers: 3)
Steel in Translation     Hybrid Journal  
Steel Research International     Hybrid Journal   (Followers: 25)
Stochastic Analysis and Applications     Hybrid Journal   (Followers: 2)
Stochastic Processes and their Applications     Hybrid Journal   (Followers: 5)
Stochastics and Dynamics     Hybrid Journal  
Strain     Hybrid Journal   (Followers: 2)
Strategic Planning for Energy and the Environment     Hybrid Journal   (Followers: 4)
Studies in Engineering and Technology     Open Access  
Studies in Interface Science     Full-text available via subscription   (Followers: 1)
Studies in Logic and Practical Reasoning     Full-text available via subscription  
Studies in Surface Science and Catalysis     Full-text available via subscription   (Followers: 1)
Superconductor Science and Technology     Hybrid Journal   (Followers: 2)
Surface Engineering     Hybrid Journal   (Followers: 3)
Surface Review and Letters     Hybrid Journal  
Surface Science Reports     Full-text available via subscription   (Followers: 13)
Survey Review     Hybrid Journal   (Followers: 6)
Surveying and Land Information Science     Full-text available via subscription   (Followers: 1)
Sustainability Science     Hybrid Journal   (Followers: 8)
Sustainability Science and Engineering     Full-text available via subscription   (Followers: 4)
Sustainable Management of Sediment Resources     Full-text available via subscription  
Swiss Journal of Geosciences     Hybrid Journal  
Symmetry     Open Access  
Synthesis Lectures on Algorithms and Software in Engineering     Full-text available via subscription   (Followers: 2)
Synthesis Lectures on Antennas     Full-text available via subscription   (Followers: 6)
Synthesis Lectures on Biomedical Engineering     Full-text available via subscription  
Synthesis Lectures on Computational Electromagnetics     Full-text available via subscription   (Followers: 5)
Synthesis Lectures on Energy and the Environment: Technology, Science, and Society     Full-text available via subscription   (Followers: 1)
Synthesis Lectures on Engineering     Full-text available via subscription  
Synthesis Lectures on Global Engineering     Full-text available via subscription  
Synthesis Lectures on Professionalism and Career Advancement for Scientists and Engineers     Full-text available via subscription   (Followers: 1)
Synthetic Metals     Hybrid Journal   (Followers: 4)
Systems Engineering     Hybrid Journal   (Followers: 6)
Systems Engineering Procedia     Open Access  
Systems Research Forum     Hybrid Journal  
Systems Science & Control Engineering     Open Access   (Followers: 5)
Technological Engineering     Open Access  
Technologies     Open Access   (Followers: 1)
TECHNOLOGY     Hybrid Journal  
Technology and Innovation     Full-text available via subscription   (Followers: 3)
Technology in Society     Hybrid Journal   (Followers: 4)
Technometrics     Full-text available via subscription   (Followers: 6)
Tecnologia, Ciencia, Educacion     Open Access   (Followers: 1)
Tecnura     Open Access  
Telecommunications Policy     Hybrid Journal   (Followers: 29)
Terahertz Science and Technology, IEEE Transactions on     Hybrid Journal   (Followers: 2)
Textile Science and Technology     Full-text available via subscription   (Followers: 3)
The Journal of Supercomputing     Hybrid Journal   (Followers: 1)
The Scientific World Journal     Open Access  
Theoretical and Computational Fluid Dynamics     Hybrid Journal   (Followers: 14)
Theoretical Issues in Ergonomics Science     Hybrid Journal   (Followers: 3)
Thermal Engineering     Hybrid Journal   (Followers: 7)
Tikrit Journal of Engineering Science     Open Access  
tm - Technisches Messen     Hybrid Journal   (Followers: 2)
Topics in Catalysis     Hybrid Journal   (Followers: 1)
Traffic Injury Prevention     Hybrid Journal   (Followers: 63)
TRANSACTIONS of the VŠB - Technical University of Ostrava, Safety Engineering Series     Open Access   (Followers: 1)
Transactions of Tianjin University     Full-text available via subscription  
Transport and Telecommunication Journal     Open Access   (Followers: 4)
Transport World Africa     Full-text available via subscription   (Followers: 3)
Transportation Research Record : Journal of the Transportation Research Board     Full-text available via subscription   (Followers: 34)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 5)
Trends in Applied Sciences Research     Open Access   (Followers: 1)
Tribology in Industry     Open Access   (Followers: 1)
Tribology International     Hybrid Journal   (Followers: 41)
Tribology Letters     Hybrid Journal   (Followers: 5)
Tribology Transactions     Hybrid Journal   (Followers: 33)
Ultramicroscopy     Hybrid Journal   (Followers: 2)
Uludağ University Journal of The Faculty of Engineering     Open Access  
Universal Journal of Applied Science     Open Access   (Followers: 2)
Universal Journal of Engineering Science     Open Access   (Followers: 1)
Utilities Policy     Hybrid Journal   (Followers: 2)
Vacuum     Hybrid Journal   (Followers: 12)
Virtual and Physical Prototyping     Hybrid Journal   (Followers: 3)
Visualization in Engineering     Open Access  
Walailak Journal of Science and Technology     Open Access  
Waste and Biomass Valorization     Hybrid Journal   (Followers: 1)
Waste Management Series     Full-text available via subscription   (Followers: 2)
Waves in Random and Complex Media     Hybrid Journal  
Waves, Wavelets and Fractals     Open Access  
Wear     Hybrid Journal   (Followers: 28)
Welding in the World     Hybrid Journal   (Followers: 3)
West African Journal of Industrial and Academic Research     Open Access   (Followers: 1)
Women in Engineering Magazine, IEEE     Full-text available via subscription   (Followers: 12)
World Journal of Engineering     Full-text available via subscription   (Followers: 3)
World Journal of Engineering and Technology     Open Access  
World Journal of Environmental Engineering     Open Access   (Followers: 2)
World Pumps     Full-text available via subscription   (Followers: 2)
World Science and Technology     Full-text available via subscription   (Followers: 1)
ZDM     Hybrid Journal  
Zede Journal     Open Access  
Zeitschrift fur Energiewirtschaft     Hybrid Journal  

  First | 1 2 3 4 5 6 | Last

Journal Cover Journal of Computational and Nonlinear Dynamics
  [SJR: 0.58]   [H-I: 27]   [6 followers]  Follow
   Full-text available via subscription Subscription journal
   ISSN (Print) 1555-1415 - ISSN (Online) 1555-1423
   Published by ASME International Homepage  [25 journals]
  • Identification and Analysis of Artifacts in Amplitude Modulated Atomic
           Force Microscopy Array Operation
    • Authors: Jackson S; Gutschmidt S.
      Abstract: To increase measurement throughput of atomic force microscopy (AFM), multiple cantilevers can be placed in close proximity to form an array for parallel throughput. In this paper, we have measured the relationship between amplitude and tip-sample separation distance for an array of AFM cantilevers on a shared base actuated at a constant frequency and amplitude. The data show that discontinuous jumps in output amplitude occur within the response of individual beams. This is a phenomenon that does not occur for a standard, single beam system. To gain a better understanding of the coupled array response, a macroscale experiment and mathematical model are used to determine how parameter space alters the measured amplitude. The results demonstrate that a cusp catastrophe bifurcation occurs due to changes in individual beam resonant frequency, as well as significant zero-frequency coupling at the point of jump-to-contact. Both of these phenomena are shown to account for the amplitude jumps observed in the AFM array.
      PubDate: Wed, 17 May 2017 00:00:00 GMT
  • Nonlinear Reduced-Order Models for Aerodynamic Lift of Oscillating
           Airfoils 2
    • Authors: Khalid M; Akhtar I.
      Abstract: For the present study, setting Strouhal number as the control parameter, we perform numerical simulations for the flow over oscillating NACA-0012 airfoil at a Reynolds number of 1000. This study reveals that aerodynamic forces produced by oscillating airfoils are independent of the initial kinematic conditions suggesting the existence of limit cycle. Frequencies present in the oscillating lift force are composed of the fundamental harmonics and its odd harmonics. Using these numerical simulations, we analyze the shedding frequencies close to the excitation frequencies. Hence, considering it as a primary resonance case, we model the unsteady lift force with a modified van der Pol oscillator. Using the method of multiple scales and spectral analysis of the steady-state computational fluid dynamics (CFD) solutions, we estimate the frequencies and the damping terms in the reduced-order model (ROM). We show the applicability of this model to all planar motions of the airfoil; heaving, pitching, and flapping. With increasing the Strouhal number, the nonlinear damping terms for all types of motion approach similar magnitudes. Another important aspect in one of the proposed model is its ability to capture the time-averaged value of the aerodynamic lift force. We also notice that increase in the magnitude of the lift force is due to the effect of destabilizing linear damping parameter.
      PubDate: Wed, 17 May 2017 00:00:00 GMT
  • Railway Air Brake Model and Parallel Computing Scheme
    • Authors: Wu Q; Cole C, Spiryagin M, et al.
      Abstract: This paper developed a detailed fluid dynamics model and a parallel computing scheme for air brake systems on long freight trains. The model consists of subsystem models for pipes, locomotive brake valves, and wagon brake valves. A new efficient hose connection boundary condition that considers pressure loss across the connection was developed. Simulations with 150 sets of wagon brake systems were conducted and validated against experimental data; the simulated results and measured results reached an agreement with the maximum difference of 15%; all important air brake system features were well simulated. Computing time was compared for simulations with and without parallel computing. The computing time for the conventional sequential computing scheme was about 6.7 times slower than real-time. Parallel computing using four computing cores decreased the computing time by 70%. Real-time simulations were achieved by parallel computing using eight computer cores.
      PubDate: Mon, 15 May 2017 00:00:00 GMT
  • Electronic Implementation of Fractional-Order Newton–Leipnik Chaotic
           System With Application to Communication
    • Authors: Rafiq Dar M; Ali Kant N, Ahmad Khanday F.
      Abstract: A complementary metal oxide semiconductor-operational transconductance amplifier (CMOS-OTA)-based implementation of fractional-order Newton–Leipnik chaotic system is introduced in this paper. The proposed circuit offers the advantages of electronic tunability of system order and on-chip integration due to MOS only design. The double strange attractor chaotic behavior of the system in consideration for an order of 2.9 has been demonstrated, and effectiveness of this chaotic system in preliminary secure message communication has also been presented. The theoretical predictions of the proposed implementation have been verified by hspice simulator using Austrian Microsystem (AMS) 0.35 μm CMOS process and subsequently compared with matlab simulink results. The power consumption of the system was 103.6 μW for standalone Newton–Leipnik chaotic generator.
      PubDate: Mon, 15 May 2017 00:00:00 GMT
  • An Efficient Numerical Simulation for Solving Dynamical Systems With
    • Authors: Ahmadian A; Salahshour S, Chan C, et al.
      Abstract: In a wide range of real-world physical and dynamical systems, precise defining of the uncertain parameters in their mathematical models is a crucial issue. It is well known that the usage of fuzzy differential equations (FDEs) is a way to exhibit these possibilistic uncertainties. In this research, a fast and accurate type of Runge–Kutta (RK) methods is generalized that are for solving first-order fuzzy dynamical systems. An interesting feature of the structure of this technique is that the data from previous steps are exploited that reduce substantially the computational costs. The major novelty of this research is that we provide the conditions of the stability and convergence of the method in the fuzzy area, which significantly completes the previous findings in the literature. The experimental results demonstrate the robustness of our technique by solving linear and nonlinear uncertain dynamical systems.
      PubDate: Thu, 04 May 2017 00:00:00 GMT
  • Estimation of Maximum Finger Tapping Frequency Using Musculoskeletal
           Dynamic Simulations
    • Authors: Shourijeh M; Razavian R, McPhee J.
      Abstract: A model for forward dynamic simulation of the rapid tapping motion of an index finger is presented. The finger model was actuated by two muscle groups: one flexor and one extensor. The goal of this analysis was to estimate the maximum tapping frequency that the index finger can achieve using forward dynamics simulations. To achieve this goal, each muscle excitation signal was parameterized by a seventh-order Fourier series as a function of time. Simulations found that the maximum tapping frequency was 6 Hz, which is reasonably close to the experimental data. Amplitude attenuation (37% at 6 Hz) due to excitation/activation filtering, as well as the inability of muscles to produce enough force at high contractile velocities, are factors that prevent the finger from moving at higher frequencies. Musculoskeletal models have the potential to shed light on these restricting mechanisms and help to better understand human capabilities in motion production.
      PubDate: Thu, 04 May 2017 00:00:00 GMT
  • Energy Straggling Function by F α -Calculus
    • Authors: Ashrafi S; Golmankhaneh A.
      Abstract: In this manuscript, we have used the recently developed Fα-calculus to calculate the energy straggling function through the fractal distributed structures. We have shown that such a fractal structure of space causes the fractal pattern of the energy loss. Also, we have offered Fα-differential Fokker–Planck equation for thick fractal absorbers.
      PubDate: Thu, 04 May 2017 00:00:00 GMT
  • Enhancing the Weak Signal With Arbitrary High-Frequency by Vibrational
           Resonance in Fractional-Order Duffing Oscillators
    • Authors: Yang JH; Sanjuán MF, Liu HG.
      Abstract: When the traditional vibrational resonance (VR) occurs in a nonlinear system, a weak character signal is enhanced by an appropriate high-frequency auxiliary signal. Here, for the harmonic character signal case, the frequency of the character signal is usually smaller than 1 rad/s. The frequency of the auxiliary signal is dozens of times of the frequency of the character signal. Moreover, in the real world, the characteristic information is usually indicated by a weak signal with a frequency in the range from several to thousands rad/s. For this case, the weak high-frequency signal cannot be enhanced by the traditional mechanism of VR, and as such, the application of VR in the engineering field could be restricted. In this work, by introducing a scale transformation, we transform high-frequency excitations in the original system to low-frequency excitations in a rescaled system. Then, we make VR to occur at the low frequency in the rescaled system, as usual. Meanwhile, the VR also occurs at the frequency of the character signal in the original system. As a result, the weak character signal with arbitrary high-frequency can be enhanced. To make the rescaled system in a general form, the VR is investigated in fractional-order Duffing oscillators. The form of the potential function, the fractional order, and the reduction scale are important factors for the strength of VR.
      PubDate: Thu, 04 May 2017 00:00:00 GMT
  • Vibration Control of Two-Degree-of-Freedom Structures Utilizing Sloshing
           in Nearly Square Tanks
    • Authors: Ikeda T; Harata Y, Ninomiya S.
      Abstract: This paper investigates the vibration control of a towerlike structure with degrees of freedom utilizing a square or nearly square tuned liquid damper (TLD) when the structure is subjected to horizontal, harmonic excitation. In the theoretical analysis, when the two natural frequencies of the two-degree-of-freedom (2DOF) structure nearly equal those of the two predominant sloshing modes, the tuning condition, 1:1:1:1, is nearly satisfied. Galerkin's method is used to derive the modal equations of motion for sloshing. The nonlinearity of the hydrodynamic force due to sloshing is considered in the equations of motion for the 2DOF structure. Linear viscous damping terms are incorporated into the modal equations to consider the damping effect of sloshing. Van der Pol's method is employed to determine the expressions for the frequency response curves. The influences of the excitation frequency, the tank installation angle, and the aspect ratio of the tank cross section on the response curves are examined. The theoretical results show that whirling motions and amplitude-modulated motions (AMMs), including chaotic motions, may occur in the structure because swirl motions and Hopf bifurcations, followed by AMMs, appear in the tank. It is also found that a square TLD works more effectively than a conventional rectangular TLD, and its performance is further improved when the tank width is slightly increased and the installation angle is equal to zero. Experiments were conducted in order to confirm the validity of the theoretical results.
      PubDate: Thu, 04 May 2017 00:00:00 GMT
  • A Study on the Dynamics of Spatial Mechanisms With Frictional Spherical
           Clearance Joints
    • Authors: Marques F; Isaac F, Dourado N, et al.
      Abstract: An investigation on the dynamic modeling and analysis of spatial mechanisms with spherical clearance joints including friction is presented. For this purpose, the ball and the socket, which compose a spherical joint, are modeled as two individual colliding components. The normal contact-impact forces that develop at the spherical clearance joint are determined by using a continuous force model. A continuous analysis approach is used here with a Hertzian-based contact force model, which includes a dissipative term representing the energy dissipation during the contact process. The pseudopenetration that occurs between the potential contact points of the ball and the socket surface, as well as the indentation rate play a crucial role in the evaluation of the normal contact forces. In addition, several different friction force models based on the Coulomb's law are revisited in this work. The friction models utilized here can accommodate the various friction regimens and phenomena that take place at the contact interface between the ball and the socket. Both the normal and tangential contact forces are evaluated and included into the systems' dynamics equation of motion, developed under the framework of multibody systems formulations. A spatial four-bar mechanism, which includes a spherical joint with clearance, is used as an application example to examine and quantify the effects of various friction force models, clearance sizes, and the friction coefficients.
      PubDate: Thu, 04 May 2017 00:00:00 GMT
  • Stability of Damped Skateboards Under Human Control
    • Authors: Varszegi B; Takacs D, Stepan G.
      Abstract: A simple mechanical model of the skateboard–skater system is analyzed, in which a linear proportional-derivative (PD) controller with delay is included to mimic the effect of human control. The equations of motion of the nonholonomic system are derived with the help of the Gibbs–Appell method. The linear stability analysis of the rectilinear motion is carried out analytically in closed form. It is shown that how the control gains have to be varied with respect to the speed of the skateboard in order to stabilize the uniform motion. The critical reflex delay of the skater is determined as functions of the speed, position of the skater on the board, and damping of the skateboard suspension system. Based on these, an explanation is given for the experimentally observed dynamic behavior of the skateboard–skater system at high speed.
      PubDate: Thu, 04 May 2017 00:00:00 GMT
  • A Special Hybrid Projective Synchronization in Symmetric Chaotic System
           With Unknown Parameter
    • Authors: Liu H; Yu H, Zhu Z.
      Abstract: A novel synchronization scheme called special hybrid projective synchronization (SHPS), in which different state variables can synchronize up to same positive or negative scaling factors, is proposed in this paper. For all the symmetric chaotic systems, research results demonstrate that the SHPS can be realized with a single-term linear controller. Taking unified chaotic system with unknown parameter as an example, based on Lyapunov stability theory, some sufficient conditions and a parameter update law are derived for the implementation of SPHS, which are verified by some corresponding numerical simulations.
      PubDate: Thu, 04 May 2017 00:00:00 GMT
  • Flutter Control of a Two-Degrees-of-Freedom Airfoil Using a Nonlinear
           Tuned Vibration Absorber
    • Authors: Malher A; Touzé C, Doaré O, et al.
      Abstract: The influence of a nonlinear tuned vibration absorber (NLTVA) on the airfoil flutter is investigated. In particular, its effect on the instability threshold and the potential subcriticality of the bifurcation is analyzed. For that purpose, the airfoil is modeled using the classical pitch and plunge aeroelastic model together with a linear approach for the aerodynamic loads. Large amplitude motions of the airfoil are taken into account with nonlinear restoring forces for the pitch and plunge degrees-of-freedom. The two cases of a hardening and a softening spring behavior are investigated. The influence of each NLTVA parameter is studied, and an optimum tuning of these parameters is found. The study reveals the ability of the NLTVA to shift the instability, avoid its possible subcriticality, and reduce the limit cycle oscillations (LCOs) amplitude.
      PubDate: Thu, 04 May 2017 00:00:00 GMT
  • A Modified Two-Timescale Incremental Harmonic Balance Method for
           Steady-State Quasi-Periodic Responses of Nonlinear Systems
    • Authors: Ju RR; Fan WW, Zhu WD, et al.
      Abstract: A modified two-timescale incremental harmonic balance (IHB) method is introduced to obtain quasi-periodic responses of nonlinear dynamic systems with combinations of two incommensurate base frequencies. Truncated Fourier coefficients of residual vectors of nonlinear algebraic equations are obtained by a frequency mapping-fast Fourier transform procedure, and complex two-dimensional (2D) integration is avoided. Jacobian matrices are approximated by Broyden's method and resulting nonlinear algebraic equations are solved. These two modifications lead to a significant reduction of calculation time. To automatically calculate amplitude–frequency response surfaces of quasi-periodic responses and avoid nonconvergent points at peaks, an incremental arc-length method for one timescale is extended for quasi-periodic responses with two timescales. Two examples, Duffing equation and van der Pol equation with quadratic and cubic nonlinear terms, both with two external excitations, are simulated. Results from the modified two-timescale IHB method are in excellent agreement with those from Runge–Kutta method. The total calculation time of the modified two-timescale IHB method can be more than two orders of magnitude less than that of the original quasi-periodic IHB method when complex nonlinearities exist and high-order harmonic terms are considered.
      PubDate: Tue, 18 Apr 2017 00:00:00 GMT
  • Forward Static Optimization in Dynamic Simulation of Human Musculoskeletal
           Systems: A Proof-of-Concept Study
    • Authors: Shourijeh MS; Mehrabi N, McPhee J.
      Abstract: Static optimization (SO) has been used extensively to solve the muscle redundancy problem in inverse dynamics (ID). The major advantage of this approach over other techniques is the computational efficiency. This study discusses the possibility of applying SO in forward dynamics (FD) musculoskeletal simulations. The proposed approach, which is entitled forward static optimization (FSO), solves the muscle redundancy problem at each FSO time step while tracking desired kinematic trajectories. Two examples are showcased as proof of concept, for which results of both dynamic optimization (DO) and FSO are presented for comparison. The computational costs are also detailed for comparison. In terms of simulation time and quality of muscle activation prediction, FSO is found to be a suitable method for solving forward dynamic musculoskeletal simulations.
      PubDate: Mon, 17 Apr 2017 00:00:00 GMT
  • A Simple Shear and Torsion-Free Beam Model for Multibody Dynamics
    • Authors: Carlos García Orden J; Cuenca Queipo J.
      Abstract: This paper describes a very simple beam model, amenable to be used in multibody applications, for cases where the effects of torsion and shear are negligible. This is the case of slender rods connecting different parts of many space mechanisms, models useful in polymer physics, computer animation, etc. The proposed new model follows a lumped parameter method that leads to a rotation-free formulation. Axial stiffness is represented by a standard nonlinear truss model, while bending is modeled with a force potential. Several numerical experiments are carried out in order to assess accuracy, which is usually the main drawback of this type of approach. Results reveal a remarkable accuracy in nonlinear dynamical problems, suggesting that the proposed model is a valid alternative to more sophisticated approaches.
      PubDate: Mon, 17 Apr 2017 00:00:00 GMT
  • Steering a Chaplygin Sleigh Using Periodic Impulses
    • Authors: Tallapragada P; Fedonyuk V.
      Abstract: The control of the motion of nonholonomic systems is of practical importance from the perspective of robotics. In this paper, we consider the dynamics of a cartlike system that is both propelled forward by motion of an internal momentum wheel. This is a modification of the Chaplygin sleigh, a canonical nonholonomic system. For the system considered, the momentum wheel is the sole means of locomotive thrust as well the only control input. We first derive an analytical expression for the change in the heading angle of the sleigh as a function of its initial velocity and angular velocity. We use this solution to design an open-loop control strategy that changes the orientation of sleigh to any desired angle. The algorithm utilizes periodic impulsive torque inputs via the motion of the momentum wheel.
      PubDate: Mon, 27 Mar 2017 00:00:00 GMT
  • Vibrations of a Simply Supported Cross Flow Heat Exchanger Tube With Axial
           Load and Loose Supports
    • Authors: Sadath A; Vinu VV, Vyasarayani CP.
      Abstract: In this work, a mathematical model is developed for simulating the vibrations of a single flexible cylinder under crossflow. The flexible tube is subjected to an axial load and has loose supports. The equation governing the dynamics of the tube under the influence of fluid forces (modeled using quasi-steady approach) is a partial delay differential equation (PDDE). Using the Galerkin approximation, the PDDE is converted into a finite number of delay differential equations (DDE). The obtained DDEs are used to explore the nonlinear dynamics and stability characteristics of the system. Both analytical and numerical techniques were used for analyzing the problem. The results indicate that, with high axial loads and for flow velocities beyond certain critical values, the system can undergo flutter or buckling instability. Post-flutter instability, the amplitude of vibration grows until it impacts with the loose support. With a further increase in the flow velocity, through a series of period doubling bifurcations the tube motion becomes chaotic. The critical flow velocity is same with and without the loose support. However, the loose support introduces chaos. It was found that when the axial load is large, the linearized analysis overestimates the critical flow velocity. For certain high flow velocities, limit cycles exist for axial loads beyond the critical buckling load.
      PubDate: Thu, 09 Mar 2017 00:00:00 GMT
  • Resonance Responses of Geometrically Imperfect Functionally Graded
           Extensible Microbeams
    • Authors: Ghayesh MH; Farokhi H, Gholipour A, et al.
      Abstract: This paper aims at analyzing the size-dependent nonlinear dynamical behavior of a geometrically imperfect microbeam made of a functionally graded (FG) material, taking into account the longitudinal, transverse, and rotational motions. The size-dependent property is modeled by means of the modified couple stress theory, the shear deformation and rotary inertia are modeled using the Timoshenko beam theory, and the graded material property in the beam thickness direction is modeled via the Mori–Tanaka homogenization technique. The kinetic and size-dependent potential energies of the system are developed as functions of the longitudinal, transverse, and rotational motions. On the basis of an energy method, the continuous models of the system motion are obtained. Upon application of a weighted-residual method, the reduced-order model is obtained. A continuation method along with an eigenvalue extraction technique is utilized for the nonlinear and linear analyses, respectively. A special attention is paid on the effects of the material gradient index, the imperfection amplitude, and the length-scale parameter on the system dynamical response.
      PubDate: Thu, 09 Mar 2017 00:00:00 GMT
  • Adaptive Semi-Implicit Integrator for Articulated Mechanical Systems
    • Authors: Hewlett J; Kovacs L, Callejo A, et al.
      Abstract: This paper concerns the dynamic simulation of constrained mechanical systems in the context of real-time applications and stable integrators. The goal is to adaptively find a balance between the stability of an over-damped implicit scheme and the energetic consistency of the symplectic, semi-implicit Euler scheme. As a starting point, we investigate in detail the properties of a recently proposed timestepping scheme, which approximates a full nonlinear implicit solution with a single linear system, without compromising stability. This scheme introduces a geometric stiffness term that improves numerical stability up to a certain time-step size, but it does so at the cost of large mechanical dissipation in comparison to the traditional constrained dynamics formulation. Dissipation is sometimes undesirable from a mechanical point of view, especially if the dissipation is not quantified. In this paper, we propose to use an additional control parameter to regulate “how implicit” the Jacobian matrix is, and change the degree to which the geometric stiffness term contributes. For the selection of this parameter, adaptive schemes are proposed based on the monitoring of energy drift. The proposed adaptive method is verified through the simulation of open-chain systems.
      PubDate: Thu, 09 Mar 2017 00:00:00 GMT
  • A New Numerical Method for Solving Nonlinear Fractional
           Fokker–Planck Differential Equations
    • Authors: Guo B; Jiang W, Zhang C.
      Abstract: The nonlinear fractional-order Fokker–Planck differential equations have been used in many physical transport problems which take place under the influence of an external force filed. Therefore, high-accuracy numerical solutions are always needed. In this article, reproducing kernel theory is used to solve a class of nonlinear fractional Fokker–Planck differential equations. The main characteristic of this approach is that it induces a simple algorithm to get the approximate solution of the equation. At the same time, an effective method for obtaining the approximate solution is established. In addition, some numerical examples are given to demonstrate that our method has lesser computational work and higher precision.
      PubDate: Thu, 09 Mar 2017 00:00:00 GMT
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