Chaotic Vibrations of Sector-Type Spherical Shells

2008 ◽  
Vol 3 (4) ◽  
Author(s):  
A. V. Krysko ◽  
J. Awrejcewicz ◽  
I. V. Papkova
Keyword(s):  
Nonlinear Dynamics ◽  
Chaotic Dynamics ◽  
Static Stability ◽  
Control Parameters ◽  
Spherical Shells ◽  
Spherical Cap ◽  
Chaotic Vibrations ◽  
Novel Method ◽  
Sector Type ◽  
Mechanical Objects

In this work, chaotic vibrations of shallow sector-type spherical shells are studied. A sector-type shallow shell is understood as a shell defined by a sector with associated boundary conditions and obtained by cutting a spherical shell for a given angle θk, or it is a sector of a shallow spherical cap associated with the mentioned angle. Both static stability and complex nonlinear dynamics of the mentioned mechanical objects subjected to transversal uniformly distributed sign-changeable load are analyzed, and the so-called vibration charts and scales regarding the chosen control parameters are reported. In particular, scenarios of transition from regular to chaotic dynamics of the mentioned shells are investigated. A novel method to control chaotic dynamics of the studied flexible spherical shells driven by transversal sign-changeable load via synchronized action of the sign-changeable antitorque is proposed and applied. All investigations are carried out within the fields of qualitative theory of differential equations and nonlinear dynamics.

scholarly journals Regular and Chaotic Dynamics of Flexible Plates

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
J. Awrejcewicz ◽  
E. Yu. Krylova ◽  
I.V. Papkova ◽  
V. A. Krysko
Keyword(s):  
Nonlinear Dynamics ◽  
Hopf Bifurcation ◽  
Chaotic Dynamics ◽  
Rectangular Plates ◽  
Control Parameters ◽  
Periodic Load ◽  
Chaotic Vibrations ◽  
Flexible Plates ◽  
Independent Variable ◽  
Time Periodic

Nonlinear dynamics of flexible rectangular plates subjected to the action of longitudinal and time periodic load distributed on the plate perimeter is investigated. Applying both the classical Fourier and wavelet analysis we illustrate three different Feigenbaum type scenarios of transition from a regular to chaotic dynamics. We show that the system vibrations change with respect not only to the change of control parameters, but also to all fixed parameters (system dynamics changes when the independent variable, time, increases). In addition, we show that chaotic dynamics may appear also after the second Hopf bifurcation. Curves of equal deflections (isoclines) lose their previous symmetry while transiting into chaotic vibrations.

scholarly journals Investigation of the Effect of Additive White Noise on the Dynamics of Contact Interaction of the Beam Structure

2019 ◽  
Author(s):  
Ольга Салтыкова ◽  
Olga Saltykova ◽  
Александр Кречин ◽  
Alexander Krechin
Keyword(s):  
Nonlinear Dynamics ◽  
White Noise ◽  
Contact Interaction ◽  
Geometric Nonlinearity ◽  
Chaotic Dynamics ◽  
Kutta Method ◽  
Beam Structure ◽  
Runge Kutta Method ◽  
Additive White Noise ◽  
The Finite Difference Method

The purpose of this work is to study and scientific visualization the effect of additive white noise on the nonlinear dynamics of beam structure contact interaction, where beams obey the kinematic hypotheses of the first and second approximation. When constructing a mathematical model, geometric nonlinearity according to the T. von Karman model and constructive nonlinearity are taken into account. The beam structure is under the influence of an external alternating load, as well as in the field of additive white noise. The chaotic dynamics and synchronization of the contact interaction of two beams is investigated. The resulting system of partial differential equations is reduced to a Cauchy problem by the finite difference method and then solved by the fourth order Runge-Kutta method.

A Mechanical Filter Concept to Suppress Crane Load Oscillations

1997 ◽  
Author(s):  
B. Balachandran ◽  
Y.-Y. Li
Keyword(s):  
Nonlinear Dynamics ◽  
Dynamical Systems ◽  
Control Parameters ◽  
Pivot Point ◽  
Preliminary Results ◽  
Scalar Control ◽  
Load Response ◽  
Mechanical Filter ◽  
Circular Track ◽  
Ship Roll

Abstract In this article, preliminary results obtained in the exploration of a mechanical filter concept for suppressing crane-load oscillations on a ship vessel are presented. The pivot point about which the load oscillates is constrained to follow a circular track in the considered filter. The governing dynamical systems for the cases with and without the filter are presented, and the nonlinear dynamics of these systems is studied with respect to quasi-static variation of different scalar control parameters. It is shown that the presence of the filter helps in eliminating some of the sub-critical bifurcations that may arise in the crane-load response during periodic ship-roll excitations.

scholarly journals Multiconsensus of Nonlinear Multiagent Systems with Intermittent Communication

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Jie Chen ◽  
Guang-Hui Xu ◽  
Liang Geng
Keyword(s):  
Nonlinear Dynamics ◽  
Lyapunov Function ◽  
Multiagent Systems ◽  
Closed Loop ◽  
Sufficient Conditions ◽  
Control Parameters ◽  
Numerical Examples ◽  
Relative Information ◽  
Loop Dynamics ◽  
Intermittent Communication

Compared with single consensus, the multiconsensus of multiagent systems with nonlinear dynamics can reflect some real-world cases. This paper proposes a novel distributed law based only on intermittent relative information to achieve the multiconsensus. By constructing an appropriate Lyapunov function, sufficient conditions on control parameters are derived to undertake the reliability of closed-loop dynamics. Ultimately, the availability of results is completely validated by these numerical examples.

Nonlinear Dynamics of Upright Human Balance While Using a Passive-Cane

2016 ◽  
Author(s):  
James R. Chagdes ◽  
Joao P. Freire ◽  
Amit Shukla
Keyword(s):  
Nonlinear Dynamics ◽  
Mathematical Model ◽  
Assistive Technology ◽  
Treatment Plan ◽  
Assistive Technologies ◽  
Feedback Gain ◽  
Control Parameters ◽  
Human Posture ◽  
Inverted Pendulum Model ◽  
Potential Applications

Recent mathematical models of human posture have been explored to better understand the space of control parameters that result in stable upright balance. These models have demonstrated that there are two types of instabilities — a leaning instability and an instability leading to excessive oscillation. While these models provide insight into the stability of upright bipedal stance, they are not sufficient for individuals that require the aid of assistive technologies, such as a passive-cane or a walker. Without a valid model one is unable to understand the control parameters required for maintain upright posture or if similar instabilities even exist when assistive technologies are used. Therefore in this study, we developed a mathematical model of human posture while using a passive-cane to examine the nonlinear dynamics of stance. First, we developed a simple mathematical model of cane assisted human stance by adapting the inverted pendulum model of Chagdes et al., [1]. We modeled the human body, upper arm, forearm, cane, and ground as a two-degree-of-freedom, five-bar-linkage with pin joints representing the ankle, shoulder, elbow, and wrist joints. Second, we investigate upright stability in the parameter space of feedback gain and time-delay. We hypothesize that the analysis will show similar instabilities compared to that of a human standing without assistive technology. We also hypothesize that the space of control parameters which stabilize upright equilibrium posture will increase when a cane is incorporated. This study has two potential applications. First, the developed mathematical model could allow clinicians to better assess technology assisted balance and if needed help clinicians to customize a treatment plan for an individual that allows them to avoid unstable postural dynamics. Second, the mathematical model can be used to design customized assistive technology for people of difference physical properties and impairments.

On the Chaotic Vibrations of Electrostatically Actuated Arch Micro/Nano Resonators: A Parametric Study

2015 ◽  
Vol 25 (08) ◽  
pp. 1550106 ◽  
Author(s):  
Farid Tajaddodianfar ◽  
Mohammad Reza Hairi Yazdi ◽  
Hossein Nejat Pishkenari
Keyword(s):  
Nonlinear Dynamics ◽  
Nonlinear Partial Differential Equation ◽  
Beam Theory ◽  
Reduced Order ◽  
Electrostatically Actuated ◽  
Chaotic Vibrations ◽  
Numerical Tools ◽  
The Galerkin Method ◽  
Euler Bernoulli Beam ◽  
Insight Into

Motivated by specific applications, electrostatically actuated bistable arch shaped micro-nano resonators have attracted growing attention in the research community in recent years. Nevertheless, some issues relating to their nonlinear dynamics, including the possibility of chaos, are still not well known. In this paper, we investigate the chaotic vibrations of a bistable resonator comprised of a double clamped initially curved microbeam under combined harmonic AC and static DC distributed electrostatic actuation. A reduced order equation obtained by the application of the Galerkin method to the nonlinear partial differential equation of motion, given in the framework of Euler–Bernoulli beam theory, is used for the investigation in this paper. We numerically integrate the obtained equation to study the chaotic vibrations of the proposed system. Moreover, we investigate the effects of various parameters including the arch curvature, the actuation parameters and the quality factor of the resonator, which are effective in the formation of both static and dynamic behaviors of the system. Using appropriate numerical tools, including Poincaré maps, bifurcation diagrams, Fourier spectrum and Lyapunov exponents we scrutinize the effects of various parameters on the formation of chaotic regions in the parametric space of the resonator. Results of this work provide better insight into the problem of nonlinear dynamics of the investigated family of bistable micro/nano resonators, and facilitate the design of arch resonators for applications such as filters.

Spherical cap surface model: A novel method for predicting renal function after partial nephrectomy

2016 ◽  
Vol 23 (8) ◽  
pp. 667-672 ◽  
Author(s):  
Yizong Ding ◽  
Wen Kong ◽  
Jin Zhang ◽  
Baijun Dong ◽  
Yonghui Chen ◽  
...  
Keyword(s):  
Renal Function ◽  
Partial Nephrectomy ◽  
Surface Model ◽  
Spherical Cap ◽  
Novel Method
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