GLOBAL BIFURCATION AND CHAOS IN A VAN DER POL-DUFFING-MATHIUE SYSTEM WITH A SINGLE-WELL POTENTIAL OSCILLATOR

The global bifurcation and chaos are investigated in this paper for a van der Pol-Duffing-Mathieu system with a single-well potential oscillator by means of nonlinear dynamics. The autonomous system corresponding to the system under discussion is analytically studied to draw all global bifurcation diagrams in every parameter space. These diagrams are called basic bifurcation ones. Then fixing parameter in every space and taking the parametrically excited amplitude as a bifurcation parameter, we can observe how to evolve from a basic bifurcation diagram to a chaos pattern in terms of numerical methods. The results are sufficient to show that the system has distinct dynamic behavior. Finally, the properties of the basins of attraction are observed and the appearance of fractal basin boundaries heralding the onset of a loss of structural integrity is noted in order to consider how to control the extent and the rate of the erosion in the next paper.

Global bifurcations and multi-pulse chaotic dynamics of rectangular thin plate with one-to-one internal resonance

Global bifurcations and multi-pulse chaotic dynamics for a simply supported rectangular thin plate are studied by the extended Melnikov method. The rectangular thin plate is subject to transversal and in-plane excitation. A two-degree-of-freedom nonlinear nonautonomous system governing equations of motion for the rectangular thin plate is derived by the von Karman type equation and the Galerkin approach. A one-to- one internal resonance is considered. An averaged equation is obtained with a multi-scale method. After transforming the averaged equation into a standard form, the extended Melnikov method is used to show the existence of multi-pulse chaotic dynamics, which can be used to explain the mechanism of modal interactions of thin plates. A method for calculating the Melnikov function is given without an explicit analytical expression of homoclinic orbits. Furthermore, restrictions on the damping, excitation, and detuning parameters are obtained, under which the multi-pulse chaotic dynamics is expected. The results of numerical simulations are also given to indicate the existence of small amplitude multi-pulse chaotic responses for the rectangular thin plate.

Unilateral Global Bifurcation and One-Sign Solutions for Kirchhoff Type Problem inR^(N)

In this paper,we study the following Kirchhoff type problem:{-M(∫_(R^(N))|▽u|^(2)dx)△u=λa(x)f(u),x∈R^(N),u=0 as|x|→+∞.Unilateral global bifurcation result is established for this problem.As applications of the bifurcation result,we determine the intervals ofλfor the existence,nonexistence,and exact multiplicity of one-sign solutions for this problem.

Global bifurcations of strongly nonlinear oscillator induced by parametric and external excitation

The global bifurcation of strongly nonlinear oscillator induced by parametric and external excitation is researched. It is known that the parametric and external excitation may induce additional saddle states, and result in chaos in the phase space, which cannot be detected by applying the Melnikov method directly. A feasible solution for this problem is the combination of the averaged equations and Melnikov method. Therefore, we consider the averaged equations of the system subject to Duffing-Van der Pol strong nonlinearity by introducing the undetermined fundamental frequency. Then the bifurcation values of homoclinic structure formation are detected through the combined application of the new averaged equations with Melnikov integration. Finally, the explicit application shows the analytical conditions coincide with the results of numerical simulation even disturbing parameter is of arbitrary magnitude.

GLOBAL BIFURCATIONS IN A DISTURBED HAMILTONIAN VECTOR FIELD APPROACHING A 3:1 RESONANT POINCAR MAP (Ⅰ)

In this paper, we use a qualitative method to study global and local bifurcations in a disturbedHamiltonian vector field approaching a Poincare map in the 3:1 resonant case. We give explicitcalculation formulas to determine bifurcation parameters and draw various bifurcations and phaseportraits in the phase plane.

Unilateral global interval bifurcation for problem with mean curvature operator in Minkowski space and its applications

In this paper,we establish a unilateral global bifurcation result from interval for a class problem with mean curvature operator in Minkowski space with non-differentiable nonlinearity.As applications of the above result,we shall prove the existence of one-sign solutions to the following problem{−div(√∇v 1−|∇v|^(2))=α(x)v^(+)+β(x)v^(−)+λa(x)f(v),in B_(R)(0),v(x)=0,on∂B_(R)(0),whereλ≠=0 is a parameter,R is a positive constant and BR(0)={x∈RN:|x|<R}is the standard open ball in the Euclidean space RN(N≥1)which is centered at the origin and has radius R.v^(+)=max{v,0},v−=−min{v,0},a(x)∈C(BR(0),(0,+∞)),α(x),β(x)∈C(BR(0)),a(x),α(x)andβ(x)are radially symmetric with respect to x;f∈C(R,R),sf(s)>0 for s≠=0,and f_(0)∈[0,∞],where f0=lim_(|s|)→0 f(s)/s.We use unilateral global bifurcation techniques and the approximation of connected components to prove our main results.We also study the asymptotic behaviors of positive radial solutions asλ→+∞.

GLOBAL BIFURCATIONS IN A PERTURBED CUBIC SYSTEM WITH Z_2-SYMMETRY

In this paper we consider global and local bifurcations in disturbed planar Hamiltonianvector fields which are invariant under a rotation over π. All calculation formulas of bifurcationcurves have been obtained. Various possible distributions and the existence of limit cycles andsingular cycles in different parameter regions have been determined. It is shown that for a planarcubic differential system there are infinitely many parameters in the three-parameter space suchthat Hilbert number H(3)≥11.

Local Hopf bifurcation and global existence of periodic solutions in TCP system

This paper investigates the dynamics of a TCP system described by a first- order nonlinear delay differential equation. By analyzing the associated characteristic transcendental equation, it is shown that a Hopf bifurcation sequence occurs at the pos- itive equilibrium as the delay passes through a sequence of critical values. The explicit algorithms for determining the Hopf bifurcation direction and the stability of the bifur- cating periodic solutions are derived with the normal form theory and the center manifold theory. The global existence of periodic solutions is also established with the method of Wu （Wu, J. H. Symmetric functional differential equations and neural networks with memory. Transactions of the American Mathematical Society 350（12）, 4799-4838 （1998））.

ANALYSIS OF GLOBAL DYNAMICS IN A PARAMETRICALLY EXCITED THIN PLATE

The global bifurcations and chaos of a simply supported rectangular thin plate with parametric excitation are analyzed. The formulas of the thin plate are derived by von Karman type equation and Galerkin's approach. The method of multiple scales is used to obtain the averaged equations. Based on the averaged equations, the theory of the normal form is used to give the explicit expressions of the normal form associated with a double zero and a pair of pure imaginary eigenvalues by Maple program. On the basis of the normal form, a global bifurcation analysis of the parametrically excited rectangular thin plate is given by the global perturbation method developed by Kovacic and Wiggins. The chaotic motion of thin plate is also found by numerical simulation.

Structure of the Bifurcation Solutions for a Predator-Prey Model

A system of reaction diffusion equations modeling the predator-prey interaction in an unstirred chemostat is considered. After transforming the model, the global bifurcation theorem is used to investigate the global structure of solutions of the system with b as the bifurcation parameter.

Nonlinear Dynamic Analysis of the Whole Vehicle on Bumpy Road

Through the research into the characteristics of 7-DoF high dimensional nonlinear dynamics of a vehicle on bumpy road, the periodic movement and chaotic behavior of the vehicle were found.The methods of nonlinear frequency response analysis, global bifurcation, frequency chart and Poincaré maps were used simultaneously to derive strange super chaotic attractor.According to Lyapunov exponents calculated by Gram-Schmidt method, the unstable region was compartmentalized and the super chaotic characteristic of ...

Existence of Positive Solutions for Eigenvalue Problems of Fourth-order Elastic Beam Equations

In this paper, we investigate the positive solutions of fourth-order elastic beam equations with both end-points simply supported. By using the approximation theorem of completely continuous operators and the global bifurcation techniques, we obtain the existence of positive solutions of elastic beam equations under some conditions concerning the first eigenvalues corresponding to the relevant linear operators, when the nonlinear term is non-singular or singular, and allowed to change sign.

GLOBAL HOPF BIFURCATION IN A DELAYED PHYTOPLANKTON-ZOOPLANKTON MODEL WITH COMPETITION

In this paper, the dynamics of a delayed phytoplankton-zooplankton model is considered. Taking the delay due to the gestation of zooplankton as param- eter, we describe the local Hopf bifurcation by center manifold theorem and normal form, then we discuss the global existence of periodic solution. At last, some simulations are given to support our result.

HOPF BIFURCATION ANALYSIS OF TWO SUNFLOWER EQUATIONS

In this paper, two sunflower equations are considered. Using delay T as a parameter and applying the global Hopf bifurcation theorem, we investigate the existence of global Hopf bifurcation for the sunflower equation. Furthermore, we analyze the local Hopf bifurcation of the modified equation with nonlinear relation about stem＇s increase, including the occurrence, the bifurcation direction, the stability and the approximation expression of the bifurcating periodic solution using the theory of normal form and center manifold. Finally, the obtained results of these two equations are compared, which finds that the result about the period of their bifurcating periodic solutions is obviously different, while the bifurcation direction and stability are identical.

Complex Dynamical Behaviors in a Dual Channel Supply Chain Model with Retailer's Service Input

Based on bounded rationality,this paper established a price game model of dual channel supply chain composed of manufacturers and retailers.According to the eigenvalue of Jacobi matrix and Jury criterion,the stability of the equilibrium point is analyzed,and then the dynamic evolution process under the parameters of price adjustment speed and retailer's service input is studied through stability region,bifurcation diagram,maximum Lyapunov exponent diagram and attraction basin.The results show that the system enters chaos through flip and Neimark-Sacker bifurcation,and increase of price adjustment speed and service input value will make the system produce more dynamic behavior.In addition,it can be found that the impact of service input value on itself is much greater than that on manufacturers.Secondly,when adjustment speed is selected as bifurcation parameter,the change curve of sales price is inconsistent,in which the change of retailers mainly remains in periodic state,while manufacturers will gradually enter chaos.Finally,studies the evolution of attraction basin in which three kinds of attractors coexist.In particular,coexistence of boundary attractors and internal attractors increases the complexity of system.Therefore,enterprises need to carefully adjust parameters of the game model to control the stability of system and maintain the long-term stability of market competition.

The Existence and Stability of Steady States for a Prey-predator System with Cross Difusion of Quasilinear Fractional Type

This paper is concerned with the existence and stability of steady states for a prey-predator system with cross diffusion of quasilineax fractional type. We obtain a sufficient condition for the existence of positive steady state solutions by applying bifurcation theory and a detailed priori estimate. In virtue of the principle of exchange of stability, we prove the stability of local bifurcating solutions near the bifurcation point.

ON THE NUMBER OF LIMIT CYCLES OF A POLYNOMIAL DIFFERENTIAL SYSTEM

In this paper, we employ qualitative analysis and methods of bifurcation theory to study the maximum number of limit cycles for a polynomial system with center in global bifurcation.

Turing patterns in a reaction-diffusion epidemic model

In this paper, we investigate the spatiotemporal dynamics of a reactio^diffusion epi- demic model with zero-flux boundary conditions. The value of our study lies in two aspects： mathematically, by using maximum principle and the linearized stability theory, a priori estimates of the steady state system and the local asymptotic stability of positive constant solution are given. By using the implicit function theorem, the exis- tence and nonexistence of nonconstant positive steady states are shown. Applying the bifurcation theory, the global bifurcation structure of nonconstant positive steady states is established. Epidemiologically, through numerical simulations, under the conditions of the existence of nonconstant positive steady states, we find that the smaller the space, the easier the pattern formation; the bigger the diffusion, the easier the pattern formation. These results are beneficial to disease control, that is, we must do our best to control the diffusion of the infectious to avoid disease outbreak.