Non Linear Dynamics Research Papers (original) (raw)

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- Applied Mathematics, Economic Growth, Predator-Prey Interactions, Biodiversity

ELSEVIER Finite Elements in Analysis and Design 27 (1997) 1940 FINITE ELEMENTS IN ANALYSIS AND DESIGN Some aspects of the nonlinear finite element method MA Crisfield*, G. Jelenic, Y. Mi, HG Zhong, Z. Fan Department of Aeronautics,... more

- by Gordan Jelenić
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- Engineering, Energy Conservation, Finite element method, Mathematical Sciences
- by Argimiro R. Secchi
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- Chemical Engineering, Process Control, Stability, Process
- by David McMillan
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- Non Linear Dynamics
- by Elmar Straßburger
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- Materials Engineering, Mechanical Engineering, High Pressure, Finite Element
- by Kathy Dhanda
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- Mechanical Engineering, Energy Economics, Energy, Energy Policy
- by Ljiljana Kolar-anić
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- Biological Sciences, Cortisol, Humans, Computer Simulation
- by Stefano Lenci and +1
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- Engineering, Optimal Control, Optimization Problem, Physical sciences

Design a nonlinear controller for second order nonlinear uncertain dynamical systems (e.g., Internal Combustion Engine) is one of the most important challenging works. This paper focuses on the design of a robust backstepping adaptive feedback linearization controller (FLC) for internal combustion (IC) engine in presence of uncertainties. In order to provide high performance nonlinear methodology, feedback linearization controller is selected. Pure feedback linearization controller can be used to control of partly unknown nonlinear dynamic parameters of IC engine. In order to solve the uncertain nonlinear dynamic parameters, implement easily and avoid mathematical model base controller, Mamdani’s performance/error-based fuzzy logic methodology with two inputs and one output and 49 rules is applied to pure feedback linearization controller. The results demonstrate that the error-based fuzzy feedback linearization controller is a model-free controllers which works well in certain and partly uncertain system. Pure feedback linearization controller and error-based feedback linearization like controller with have difficulty in handling unstructured model uncertainties. To solve this problem applied backstepping-based tuning method to error-based fuzzy feedback linearization controller for adjusting the feedback linearization controller gain ( ). This controller has acceptable performance in presence of uncertainty (e.g., overshoot=1%, rise time=0.48 second, steady state error = 1.3e-9 and RMS error=1.8e-11).

- by FARZIN PILTAN and +1
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- Electrical Engineering, Robotics, Control Systems Engineering, Artificial Intelligence
- by rocco alaggio
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- Mechanical Engineering, Civil Engineering, Applied Mathematics, Non Linear Dynamics
- by Davron Matrasulov
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- Non Linear Dynamics

The dynamics of a simple dynamical system subjected to an elastic restoring force, viscous damping and dry friction forces is investigated. Self-sustained oscillations occur with non-standard attracting properties. Discontinuity of the governing equations leads to non-standard bifurcations, which are studied here, with analytical and numerical tools.

- by Bernard Cazelles
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- Animal Behaviour, Biological Sciences, Non Linear Dynamics, Deterministic Chaos
- by Kathy Dhanda
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- Agricultural Economics, Chaos Theory, Chaos/Complexity Theory, Applied Economics

With rapid development in power semiconductor
devices, the usage of power electronic systems has expanded to
new and wide application range that include residential,
commercial, aerospace and many others. However, their nonlinear behavior puts a question mark on their high efficiency.
This paper aims to develop a circuit for PFC boost converter to
observe chaos and bifurcation diagrams. It is clear that the
output storage capacitor is a main contributing parameter on
the system stability, therefore, bifurcation maps are developed
to determine the accurate minimum output capacitance value
that assures the system stability under all operating conditions

- by Abhisek Pal and +2
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- Non Linear Dynamics, Dynamical Systems and Bifurcation Theory, Dc-Dc Boost Converter
- by A. Maki
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- Psychology, Cognitive Science, Near Infrared, Time series analysis
- by K. Spentzas
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- Non Linear Dynamics, Degree of Freedom
- by A. Lakis
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- Engineering, Finite element method, Finite Element, Numerical Method

The seismic behavior of sheathed cold-formed steel (SCFS) structures is characterized by the lateral response of shear walls. Basically, if cold-formed steel (CFS) structures are designed according to the “sheathing-design” methodology, then the seismic behavior of shear walls is strongly influenced by the sheathing-to-frame connections response, characterized by a remarkable nonlinear response and a strong pinching of hysteresis loops. In this paper the results of an extensive parametric non linear dynamic analysis, carried out on one story buildings by means of incremental dynamic analysis (IDA), using an ad hoc model of the hysteresis response of SCFS shear walls, are presented. An extended number of wall configurations has been considered investigating several parameters such as sheathing panel typology, wall geometry, external screw spacing, seismic weight and soil type. Based on IDA results, three behavior factors have been defined, which take into account overstrength, ductility and both overstrength and ductility, respectively. Finally, a design nomograph for the seismic design of single-storey SCFS frame structures developed on the basis of non-linear dynamic analysis results is presented. This last aims to complete a proposal of a design methodology, already presented by the author in the last years.► The seismic behavior of sheathed CFS shear walls is under investigation. ► Parametric non linear dynamic analysis results of SCFS structures are presented. ► Three behavior factors for sheathed CFS structures have been defined. ► A nomograph for the seismic design of SCFS frame structures is presented. ► The procedure applicability is demonstrated through the design of a typical house.

- by Nikhil Ohol
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- Civil Engineering, Structures and Fire Engineering, Seismic Design, Cold Formed Steel
- by B. Pandurangan
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- Traumatic Brain Injury, Non Linear Dynamics, Materials Design, Microstructures
- by Vivek Pareek
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- Non Linear Dynamics, Phase Space
- by Rosangela Hoshi
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- Nonlinear dynamics, Heart rate variability, Humans, Female
- by Silvia Bocchi
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- Nursing, Brazil, Qualitative Research, Public Health

XI Congresso Nazionale L'ingegneria Sismica in Italia, Genova 25-29 gennaio 2004 Vulnerabilità sismica di edifici in ca realizzati negli anni '70 A. Masi, M. Vona Dipartimento di Strutture, Geotecnica, Geologia applicata... more

- by Angelo Masi
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- Non Linear Dynamics, Seismic Vulnerability, Seismic response

Human society is a complex nonequilibrium system that changes and develops constantly. Complexity, multivariability, and contradictoriness of social evolution lead researchers to a logical conclusion that any simplification, reduction, or neglect of the multiplicity of factors leads inevitably to the multiplication of error and to significant
misunderstanding of the processes under study. The view that any simple general laws are not observed at all with respect to social evolution has become totally predominant within the academic community, especially among those who specialize in the Humanities
and who confront directly in their research all the manifold unpredictability of social processes. A way to approach human society as an extremely complex system is to recognize differences of abstraction and time scale between different levels. If the main task
of scientific analysis is to detect the main forces acting on systems so as to discover fundamental laws at a sufficiently coarse scale, then abstracting from details and deviations from general rules may help to identify measurable deviations from these laws in finer
detail and shorter time scales. Modern achievements in the field of mathematical modeling suggest that social evolution can be described with rigorous and sufficiently simple macrolaws.

- by Manuel Samuelides
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- Statistical Physics, Neural Network, Synaptic Plasticity, System Theory
- by Gabriela Ulloa Contador
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- Geology, Pedogenesis, Landscape Evolution, Non Linear Dynamics

"The paper deals with the flexural failure of Reinforced Concrete elements under
blast loads. The main topics and results of a PhD thesis are here summarized, whose
aim was to develop theoretical dynamic and energy models capable of evaluating the
dynamic response of R.C. elements under explosive load.
In the original work, models with different levels of complexity were presented, but
for sake of simplicity only the simplest Single Degree Of Freedom (SDOF) system has
been here discussed. Strain-rate effects are also accounted for.
A sensitivity analysis to determine the key parameters in beam response under
blast load has been developed by means of the SDOF model. Results of numerical
simulations obtained in terms of deflection and velocity have been fitted by proper
polynomial least-square interpolation.
Among the various interpolations considering several parameters (peak load,
positive phase duration, slenderness, span length, concrete strength, reinforcement
ratio etc.) slenderness (corresponding to stiffness) and peak load prove to be the most
important parameters, but span length (corresponding to mass) is also a key
parameter. Other variables such as concrete strength and reinforcement ratio do not
seem to have a high correlation with results.
Lastly some suggestions for blast-resistant bridge design are presented."

- by Flavio Stochino
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- Civil Engineering, Structural Engineering, Concrete, Structural Dynamics
- by Paolo Di Pasquale
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- Creative Writing, Creative Writing, Critical Theory, Religion

This work presents a non-linear carrier current control technique to improve the power factor and reduce the distortion of input current in soft switched Interleaved Boost Converter (IBC). This Interleaved Power Factor Correction (IPFC) circuit is studied and investigated in MATLAB. The performance of the circuit configuration is recorded under open loop and closed loop operation. SPARTAN/FPGA is employed to execute the control technique. The vital parameters such as energy factor, voltage regulation, input power factor, input distortion factor, power losses and efficiency are computed. The hardware has been built with non-linear carrier current control strategy and the results are verified.

- by F. al-Bender and +1
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- Materials Engineering, Mechanical Engineering, Wear, Non Linear Dynamics
- by M. Saje
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- Engineering, Modeling, Energy Conservation, Finite element method

There are two alternative strategies that a designer may adopt and combine when faced with the retrofitting of a bridge: (a) the increase in the capacity or (b) the reduction in the actions of the structure. In this article, a new scheme, based on the second strategy, is proposed for the retrofit of existing multi-span simply supported (MSSS) bridges. The reduction in the actions of the bridge was mainly achieved by utilising an external restraining system consisting of I-shaped steel piles driven in the backfill soil and a slab that is the pile-cap of the piles. The restraining system was preliminarily designed and assessed in an existing MSSS bridge system, whose deck slab was made continuous. The existing and the retrofitted bridge were analysed by means of non-linear dynamic time history analysis and their response was compared in terms of serviceability and earthquake resistance performance. The study showed that the retrofitting scheme enhanced effectively the earthquake resistance of the existing bridge.

- by stergios mitoulis
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- Civil Engineering, Non Linear Dynamics

Multiparameter geophysical observatory was established in North Caucasus, near Elbrus Volcano, in 2001 by the scientists of Otto Schmidt Institute of Physics of the Earth (IPE) of Russian Academy of Sciences (RAS) with support of Institute for Nuclear Research (INR) RAS and Berbekov Kabardino-Balkar State University (KBSU) to study possible reawakening of volcanism in the region. This paper describes the instrumental equipment of monitoring investigations and data acquisition system forced into application by mid-2007, provides technical characteristics of some devices and their principles. Capacities of the observatory are shown by numerous examples. The most valuable results of instrumental measurements are presented. Based on these data, we studied the tidal deformations, which reflect the structural features of geologic environment of Elbrus volcanic center caused by magmatic bodies. Variations of the earth surface tilt and magnetic field related to the catastrophic Sumatra earthquake December 26, 2004 were recorded, and the spectrum and wavelet analyses were performed. For the first time the wave processes in various geophysical fields that reflect main dynamic features of generation and motion of a catastrophic snow avalanche directly on the observation point were observed and studied. These data underlie the mathematical model of non-linear dynamics of slope flows. Further perspectives of development of the North Caucasus Geophysical Observatory are outlined.

- by Alberto Porta
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- Neuroscience, Behavior, Cardiovascular disease, Electrocardiography
- by I. Dudurych and +1
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- Power System, Electric Power Systems, Fundamental Frequency, Non Linear Dynamics

"This paper deals with the effect of blast
loading on R.C. structures. After depicting load
and materials characteristics in blast event,
different alternative structural models are
proposed. The first approach idealizes the beam
as a single degree of freedom system, the second
models it by means of Euler-Bernoulli’s theory and
its elastic-plastic behaviour is expressed through a
nonlinear relationship between bending moment
and curvature. The effects of strain rate are taken
into consideration by introducing time-variable
coefficients into the equations of motion derived
from the two models. The comparison with some
experimental results assesses the reliability of the
approach, and a sensibility analysis of the
different involved parameters is then developed.
Slenderness and span length proved to be the key
parameters and let the Authors to find a
polynomial relation between them and the
maximum displacement/velocity of the beam."

- by Sergio Tattoni and +1
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- Civil Engineering, Structural Engineering, Structural Dynamics, Structural Reliability

In this paper, the solving of a class of both linear and nonlinear Volterra integral equations of the first kind is investigated. Here, by converting integral equation of the first kind to a linear equation of the second kind and the ordinary differential equation to integral equation we are going to solve the equation easily. The method of successive approximations (Neumann's series) is applied to solve linear and nonlinear Volterra integral equation of the second kind. Some examples are presented to illustrate methods.

- by Dr Subhamay Dutta
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- Fluid Dynamics, Non Linear Dynamics

The article presents an approach to design tubular reactors in recycle systems, based on non-linear analysis. A pseudo-homogeneous plug-flow reactor model is used. It is assumed that the separation unit delivers product and recycle streams with fixed composition. The stand-alone reactor has a unique stable steady state. The coupled reactor–separation–recycle system shows four types of conversion versus plant Damköhler number bifurcation diagrams. A feasible steady state exists only if the reactor volume exceeds a critical value. For isothermal reactor, the steady state is unique and stable. For non-isothermal reactor, one or two steady states are possible. In the second situation the low-conversion state is unstable. In some parameter regions, the unique state is unstable. The design should ensure state unicity and stability, which are favoured by large heat-transfer capacity, low coolant temperature and high reactor-inlet temperature. A case study demonstrates that these phenomena can be easily found in real plants.

- by Costin Sorin Bildea
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- Mechanical Engineering, Chemical Engineering, Thermodynamics, Design
- by Carmel Martin
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- Complex Systems Science, Information Management, Child health, Complex Systems