scholarly journals Global and Local Dynamics of a Bistable Asymmetric Composite Laminated Shell

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1690
Author(s):  
Ting Dong ◽  
Zhenkun Guo ◽  
Guoqing Jiang
Keyword(s):  
Temperature Difference ◽  
Excitation Amplitude ◽  
Global Dynamics ◽  
Base Excitation ◽  
Potential Wells ◽  
Laminated Shell ◽  
Local Dynamics ◽  
Periodic Vibration ◽  
Equilibrium Configurations ◽  
Global And Local

As bistable composite laminated plate and shell structures are often exposed to dynamic environments in practical applications, the global and local dynamics of a bistable asymmetric composite laminated shell subjected to the base excitation is presented in this paper. Temperature difference, base excitation amplitude, and detuning parameters are discussed. With the change of temperature difference, the super-critical pitchfork bifurcation occurs. Three equilibrium solutions corresponding to three equilibrium configurations (two stable configurations and one unstable configuration) can be obtained. With the increase of excitation amplitude, local and global dynamics play a leading role successively. The global dynamics between the two stable configurations behave as the periodic vibration, the quasi-periodic vibration, the chaotic vibration and dynamic snap-through when the excitation amplitude is large enough. The local dynamics that are confined to a single stable configuration behave as 1:2 internal resonance, saturation and permeation when the excitation amplitude is small. Dynamic snap-through and large-amplitude vibrations with two potential wells for the global dynamics will lead to a broad application prospect of the bistable asymmetric composite laminated shell in energy harvesting devices.

Modeling and Experimental Validations of a Piezoelectric Energy Harvester Under Combined Galloping and Base Excitations

2014 ◽  
Author(s):  
Amin Bibo ◽  
Abdessattar Abdelkefi ◽  
Mohammed F. Daqaq
Keyword(s):  
Bluff Body ◽  
Energy Harvester ◽  
Constitutive Relations ◽  
Excitation Frequency ◽  
Primary Resonance ◽  
Beam Theory ◽  
Excitation Amplitude ◽  
The Body ◽  
Base Excitation ◽  
Piezoelectric Energy

This paper develops an experimentally validated model of a piezoelectric energy harvester under combined aeroelastic-galloping and base excitations. To that end, an energy harvester consisting of a thin piezoelectric cantilever beam subjected to vibratory base excitation is considered. To permit galloping excitation, a bluff body is rigidly attached at the free end such that a net aerodynamic lift is generated as the incoming airflow separates on both sides of the body giving rise to limit cycle oscillations when the flow velocity exceeds a critical value. A nonlinear electromechanical distributed-parameter model of the harvester under the combined excitation is derived using the energy approach and by adopting the nonlinear Euler-Bernoulli beam theory, linear constitutive relations for the piezoelectric transduction, and the quasi-steady assumption for the aerodynamic loading. The partial differential equations of the system are discretized and a reduced-order-model is obtained. The mathematical model is validated by conducting a series of experiments with different loading conditions represented by wind speed, base excitation amplitude, and excitation frequency around the primary resonance.

Nonlinear Analysis of L-shaped Pipe Conveying Fluid with the Aid of Absolute Nodal Coordinate Formulation

2021 ◽  
Author(s):  
K. Zhou ◽  
H.R. Yi ◽  
Huliang Dai ◽  
H Yan ◽  
Z.L. Guo ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Flow Velocity ◽  
Absolute Nodal Coordinate Formulation ◽  
Strong Relationship ◽  
Excitation Amplitude ◽  
Pipe Conveying Fluid ◽  
Base Excitation ◽  
Absolute Nodal Coordinate ◽  
Nonlinear Behaviors ◽  
Conveying Fluid

Abstract By adopting the absolute nodal coordinate formulation, a novel and general nonlinear theoretical model, which can be applied to solve the dynamics of combined straight-curved fluid-conveying pipes with arbitrary initially configurations and any boundary conditions, is developed in the current study. Based on this established model, the nonlinear behaviors of the cantilevered L-shaped pipe conveying fluid with and without base excitations are systematically investigated. Before starting the research, the developed theoretical model is verified by performing three validation examples. Then, with the aid of this model, the static deformations, linear stability, and nonlinear self-excited vibrations of the L-shaped pipe without the base excitation are determined. It is found that the cantilevered L-shaped pipe suffers from the static deformations when the flow velocity is subcritical, and will undergo the limit-cycle motions as the flow velocity exceeds the critical value. Subsequently, the nonlinear forced vibrations of the pipe with a base excitation are explored. It is indicated that the period-n, quasi-periodic and chaotic responses can be detected for the L-shaped pipe, which has a strong relationship with the flow velocity, excitation amplitude and frequency.

Migration and Economy: Global and Local Dynamics (review)

2007 ◽  
Vol 80 (2) ◽  
pp. 629-633 ◽  
Author(s):  
Caroline. Brettell
Keyword(s):  
Local Dynamics ◽  
Global And Local

Non-Linear Piezoelectric Vibration Energy Harvesting From a Vertical Cantilever Beam With Tip Mass

2013 ◽  
Author(s):  
Onur Bilgen ◽  
S. Faruque Ali ◽  
Michael I. Friswell ◽  
Grzegorz Litak ◽  
Marc de Angelis
Keyword(s):  
Energy Harvester ◽  
Harmonic Component ◽  
Vibration Energy ◽  
Base Excitation ◽  
Vibration Energy Harvesting ◽  
Vibration Energy Harvester ◽  
Potential Wells ◽  
Non Linear ◽  
Cantilevered Beam ◽  
Tip Mass

An inverted cantilevered beam vibration energy harvester with a tip mass is evaluated for its electromechanical efficiency and power output capacity in the presence of pure harmonic, pure random and various combinations of harmonic and random base excitation cases. The energy harvester employs a composite piezoelectric material device that is bonded near the root of the beam. The tip mass is used to introduce non-linearity to the system by inducing buckling in some configurations and avoiding it in others. The system dynamics include multiple solutions and jumps between the potential wells, and these are exploited in the harvesting device. This configuration exploits the non-linear properties of the system using base excitation in conjunction with the tip mass at the end of the beam. Such nonlinear device has the potential to work well when the input excitation does not have a dominant harmonic component at a fixed frequency. The paper presents an extensive experimental analysis, results and interesting conclusions derived directly from the experiments supported by numerical simulations.

On the Proper Description of Complex Network Dynamics

2018 ◽  
Author(s):  
Chun-Lin Yang ◽  
C. Steve Suh
Keyword(s):  
Complex Networks ◽  
Complex Network ◽  
Collective Behavior ◽  
Local Level ◽  
Network Dynamics ◽  
Global Dynamics ◽  
Statistical Entropy ◽  
Network Systems ◽  
Local Dynamics ◽  
The Difference

Real-world networks are dynamical complex network systems. The dynamics of a network system is a coupling of the local dynamics with the global dynamics. The local dynamics is the time-varying behaviors of ensembles at the local level. The global dynamics is the collective behavior of the ensembles following specific laws at the global level. These laws include basic physical principles and constraints. Complex networks have inherent resilience that offsets disturbance and maintains the state of the system. However, when disturbance is potent enough, network dynamics can be perturbed to a level that ensembles no longer follow the constraint conditions. As a result, the collective behavior of a complex network diminishes and the network collapses. The characteristic of a complex network is the response of the system which is time-dependent. Therefore, complex networks need to account for time-dependency and obey physical laws and constraints. Statistical mechanics is viable for the study of multi-body dynamic systems having uncertain states such as complex network systems. Statistical entropy can be used to define the distribution of the states of ensembles. The difference between the states of ensembles define the interaction between them. This interaction is known as the collective behavior. In other words statistical entropy defines the dynamics of a complex network. Variation of entropy corresponds to the variation of network dynamics and vice versa. Therefore, entropy can serve as an indicator of network dynamics. A stable network is characterized by a specific entropy while a network on the verge of collapse is characterized by another. As the collective behavior of a complex network can be described by entropy, the correlation between the statistical entropy and network dynamics is investigated.

scholarly journals Observer Design for Nonlinear Invertible System from the View of Both Local and Global Levels

2020 ◽  
Vol 10 (22) ◽  
pp. 7966
Author(s):  
Mei Zhang ◽  
Qinmu Wu ◽  
Xiangping Chen ◽  
Boutaïeb Dahhou ◽  
Zetao Li
Keyword(s):  
Design Method ◽  
Nonlinear Process ◽  
Observer Design ◽  
Global Dynamics ◽  
State Observation ◽  
System Output ◽  
Interconnected Nonlinear Systems ◽  
Global And Local ◽  
Derivatives Of ◽  
Output Equation

This paper emphasizes the importance of the influences of local dynamics on the global dynamics of a control system. By considering an actuator as an individual, nonlinear subsystem connected with a nonlinear process subsystem in cascade, a structure of interconnected nonlinear systems is proposed which allows for global and local supervision properties of the interconnected systems. To achieve this purpose, a kind of interconnected observer design method is investigated, and the convergence is studied. One major difficulty is that a state observation can only rely on the global system output at the terminal boundary. This is because the connection point between the two subsystems is considered unable to be measured, due to physical or economic reasons. Therefore, the aim of the interconnected observer is to estimate the state vector of each subsystem and the unmeasurable connection point. Specifically, the output used in the observer of the actuator subsystem is replaced by the estimation of the process subsystem observer, while the estimation of this interconnection is treated like an additional state in the observer design of the process subsystem. Expression for this new state is achieved by calculating the derivatives of the output equation of the actuator subsystem. Numerical simulations confirm the effectiveness and robustness of the proposed observer, which highlight the significance of the work compared with state-of-the-art methods.

Evolutionary Games and Local Dynamics

2015 ◽  
Vol 17 (02) ◽  
pp. 1540016 ◽  
Author(s):  
Philippe Uyttendaele ◽  
Frank Thuijsman
Keyword(s):  
Game Theory ◽  
Population Dynamics ◽  
Evolutionary Game Theory ◽  
Evolutionary Game ◽  
Evolutionary Games ◽  
Global Dynamics ◽  
Local Interactions ◽  
Local Dynamics

In this paper, we examine several options for modeling local interactions within the framework of evolutionary game theory. Several examples show that there is a major difference between population dynamics using local dynamics versus global dynamics. Moreover, different modeling choices may lead to very diverse results.

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