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1997, Journal of Dynamics and Differential Equations
This work is concerned with the rigorous analysis of the effects of small periodic forcing (perturbations) on the dynamical systems which present some interesting phenomena known as delayed bifurcations. We study the dynamical behavior of the system ~u "r f(u, Ii + et) + sg(u, li + st, 8, t) Of u(t)l,.o ffi uo(li) + 0(8) (0.1) where uo(l) is the solution off(uo(l), I) •O and l(t)=-li+8t is a slowly varying parameter that moves past a critical point I_ of the system so that the linear stability around uo(l) changes from stable to unstable at I_. General results are given with respect to the effects of the perturbation 8g(u, I(t), e, t) to several important types of dynamical systems ~u =f(u, lj +80 (0.2) which present dynamical patterns that there exist persistent unstable solutions in the dynamical systems (delayed bifurcations) in contrast to bifurcations in the classical sense. It is shown that (1) the delayed bifurcations persist if the frequency of g(.,.,., t) on f is a constant co which is not a resonant frequency; (2) in case the frequency of g(.,.,.,t) on t is co =. co(lt + st) that is slowly varying, the resonance frequencies where the delayed bifurcations might be destructed are shifted downward or upward depending on co'(l_)>O or co'(I_) <0; and (3) delayed pitchfork (simple eigenvalue) bifurcations occur in
2018
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Nonlinear Dynamics, 2017
In this work, the dynamics of an oscillator with delayed feedback is analyzed. It is found that for certain values of the parameters, the system exhibits a phenomenon known as double Hopf bifurcation with 1:2 resonance. This singularity provokes the interaction between two oscillatory solutions, one of frequency ω and the other with frequency 2ω. By using the graphical Hopf bifurcation theorem, the system dynamics in a neighborhood of this singularity is explored. Also, with the aid of the package DDE-Biftool, some global bifurcations are detected in order to provide a better understanding of the whole scenario.
arXiv preprint arXiv:1001.1193, 2010
Proceedings of the 40th IEEE Conference on Decision and Control (Cat. No.01CH37228), 2001
Journal of Differential Equations, 2020
There are few examples of non-autonomous vector fields exhibiting complex dynamics that may be proven analytically. We analyse a family of periodic perturbations of a weakly attracting robust heteroclinic network defined on the two-sphere. We derive the first return map near the heteroclinic cycle for small amplitude of the perturbing term, and we reduce the analysis of the non-autonomous system to that of a two-dimensional map on a cylinder. Interesting dynamical features arise from a discrete-time Bogdanov-Takens bifurcation. When the perturbation strength is small the first return map has an attracting invariant closed curve that is not contractible on the cylinder. Near the centre of frequency locking there are parameter values with bistability: the invariant curve coexists with an attracting fixed point. Increasing the perturbation strength there are periodic solutions that bifurcate into a closed contractible invariant curve and into a region where the dynamics is conjugate to a full shift on two symbols.
Nonlinear Analysis-theory Methods & Applications, 1984
Journal of Sound and Vibration, 1996
International Journal of Non-linear Mechanics, 2002
W e consider an autoparametric system which consists of an oscillator, coupled with a parametrically-excited subsystem. The oscillator and the subsystem are in 1 : 1 internal resonance. The excited subsystem is in 1 : 2 parametric resonance with the external forcing. The system contains the most general type of cubic nonlinearities. Using the method of averaging and numerical bifurcation continuation, we study the dynamics of this system. In particular, we consider the stability of the semi-trivial solutions, where the oscillator is at rest and the excited subsystem performs a periodic motion. We nd various types of bifurcations, leading to non-trivial periodic or quasi-periodic solutions. We also nd numerically sequences of period-doublings, leading to chaotic solutions.
2002
This thesis is a collection of studies on coupled nonconservative oscillator systems which contain an oscillator with parametric excitation. The emphasis this study will, on the one hand, be on the bifurcations of the simple solutions such as fixed points and periodic orbits, and on the ...
Discrete and Continuous Dynamical Systems - Series B, 2004
The bifurcations of strange nonchaotic attractors in quasi-periodically forced systems are poorly understood. A simple two-parameter example is introduced which unifies previous observations of the non-smooth pitchfork bifurcation. There are two types of generalized pitchfork bifurcation which occur in this example, and the corresponding bifurcation curves can be calculated analytically. The example shows how these bifurcations are organized around a codimension two point in parameter space.
2010
Bifurcation theory is the mathematical investigation of changes in the qualitative or topological structure of a studied family. In this paper, we numerically investigate the qualitative behavior of nonlinear RLC circuit excited by sinusoidal voltage source based on the bifurcation analysis. Poincare mapping and bifurcation methods are applied to study both dynamics and qualitative properties of the periodic responses of such oscillator. As numerically illustrated here, a small variation of amplitude or frequency of the driver sinusoidal voltage may involve qualitative changes for witch the system exhibits fold, period doubling and pitchfork bifurcations. In fact, the presence of these kinds of bifurcation necessitates an examination of the role of these singularities in the dynamical behavior of circuit. Particularly, we numerically study the qualitative changes may affect number and stability of the periodic solutions and the shapes of its basins of attraction associated while app...
International Journal of Bifurcation and Chaos, 2008
We study the effect of a time-delayed feedback within a generic model for a saddle-node bifurcation on a limit cycle. Without delay the only attractor below this global bifurcation is a stable node. Delay renders the phase space infinite-dimensional and creates multistability of periodic orbits and the fixed point. Homoclinic bifurcations, period-doubling and saddle-node bifurcations of limit cycles are found in accordance with Shilnikov's theorems.
International Journal of Bifurcation and Chaos, 2001
In this paper two-dimensional systems with static bifurcations are considered. An analysis of the bifurcation behavior is proposed using a frequency domain approach. The analyzed bifurcations are known as elementary since they are the building blocks to understand other more complex singularities.
Nonlinear Dynamics, 2012
In this paper, using the local coordinate moving frame approach, we investigate bifurcations of generic heteroclinic loop with a hyperbolic equilibrium and a nonhyperbolic equilibrium which undergoes a pitchfork bifurcation. Under some generic hypotheses, the existence of homoclinic loop, heteroclinic loop, periodic orbit and three or four heteroclinic orbits is obtained. In addition, the non-coexistence conditions for homoclinic loop and periodic orbit are also given. Note that the results achieved here can be extended to higher dimensional systems.
Discrete and Continuous Dynamical Systems, 1999
Physical Review E, 2001
Experimental observations of an almost symmetric electronic circuit show complicated sequences of bifurcations. These results are discussed in the light of a theory of imperfect global bifurcations. It is shown that much of the dynamics observed in the circuit can be understood by reference to imperfect homoclinic bifurcations without constructing an explicit mathematical model of the system.
Nonlinear Analysis: Theory, Methods & Applications, 2003
Nonlinear Dynamics, 2005
We investigate the dynamics of a system consisting of a simple harmonic oscillator with small nonlinearity, small damping and small parametric forcing in the neighborhood of 2:1 resonance. We assume that the unforced system exhibits the birth of a stable limit cycle as the damping changes sign from positive to negative (a supercritical Hopf bifurcation). Using perturbation methods and numerical integration, we investigate the changes which occur in long-time behavior as the damping parameter is varied. We show that for large positive damping, the origin is stable, whereas for large negative damping a quasi-periodic behavior occurs. These two steady states are connected by a complicated series of bifurcations which occur as the damping is varied.
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