Chaotic vibrations of flexible shallow axially symmetric shells

Krysko, Anton V.; Awrejcewicz, Jan; Zakharova, Alena; Папкова, И. В.; Кrysko, V.А.

doi:10.1007/s11071-017-4013-0

“…Chaos widely exits in nature and man-made systems including those biological systems [20][21][22][23][24]. According to the famous Logistic map, it shows that the natural evolution of the population size could be chaotic.…”

Section: Introductionmentioning

confidence: 99%

SEIR modeling of the COVID-19 and its dynamics

He

¹

,

Peng

²

,

Sun

³

2020

View full text Add to dashboard Cite

In this paper, a SEIR epidemic model for the COVID-19 is built according to some general control strategies, such as hospital, quarantine and external input. Based on the data of Hubei province, the particle swarm optimization (PSO) algorithm is applied to estimate the parameters of the system. We found that the parameters of the proposed SEIR model are different for different scenarios. Then, the model is employed to show the evolution of the epidemic in Hubei province, which shows that it can be used to forecast COVID-19 epidemic situation. Moreover, by introducing the seasonality and stochastic infection the parameters, nonlinear dynamics including chaos are found in the system. Finally, we discussed the control strategies of the COVID-19 based on the structure and parameters of the proposed model.

show abstract

“…Previous studies have shown that absolute and relative power are complementary indicators that may transmit significantly different brain function data [3]. The captured EEG data on brain activity allow applying methods of nonlinear dynamics to signals, as well as in other branches of modern science, such as mechanics [4,5], radiophysics [6], history [7], etc. Time-series entropy analysis is widely used in EEG studies.…”

Section: Introductionmentioning

confidence: 99%

Visualization of EEG signal entropy in schizophrenia

Кутепов¹,

Krysko²,

Dobriyan³

et al. 2020

View full text Add to dashboard Cite

This paper describes the visualization of the study of signal entropy in two groups of subjects. Brain activity signals were obtained using electroencephalogram (EEG). Two groups of adolescents-a schizophrenic group and a control group-were the subjects of the study. For each of the participants in both groups, 16 channels were recorded. Multi-scale entropy, model entropy, and approximated entropy were analyzed for signal complexity. The results of the entropic assessments were compared in the form of topographic images. Topographic images of the head surface were obtained based on a spherical spline. The activity of brain hemispheres for both groups was compared using the mean values of the cross-correlation function. The study showed that the visualization of EEG signals could be a useful tool for classification of patients with schizophrenia and control groups. The analysis may be considered useful for the psychiatric examination of patients with schizophrenia. On the other hand, the proposed approach is useful to extend the functionality of the educative robotics. Identification of schizophrenic subjects in the group of students provided by the robotic complex on the fly helps to avoid possible antisocial behavior while applying adequate training methods.

show abstract

“…In 1963, Lorenz [2] published a paper entitled "Decisive aperiodic flow" and performed a preliminary study on chaos by numerical simulations. Krysko et al [3] studied the chaotic dynamics of flexible spherical axially symmetric shallow shells subjected to a sinusoidal transverse load, solved the governing partial nonlinear equations, estimated the signs of the largest Lyapunov exponents, and verified the reliability of chaos. Kim et al [4] investigated the chaotic vibration of a rotor system with an asymmetric nonlinear stiffness and derived the motion equation of the rotor in a fixed coordinate system under Shilnikov chaotic vibration.…”

Section: Introductionmentioning

confidence: 99%

Design and Dynamic Analysis of a Four‐Degree‐of‐Freedom Chaotic Vibrating Screen

Mingkun

¹

,

Wang

²

,

Chen

³

et al. 2021

Shock and Vibration

View full text Add to dashboard Cite

In order to address the problems of low screening efficiency, easy blocking of screen holes, and short service life of key parts commonly used in vibrating screen equipment, the TRIZ (Theory of the Solution of Inventive Problems) was applied in the present work to design a four-degree-of-freedom (4-DOF; three translational and one rotational movements) chaotic vibrating screen with a chaotic vibration exciter as the main power source and a 3-DOF (three translational movements) parallel kinetic chain as the kinematic constraint mechanism of the outer screen frame. Based on the topological structure theory, a hybrid mechanism with structure [ 4 SOC − C i 1 ∥ R i 2 ∥ R i 3 − + R , i = 1,2,3,4 ] was constructed as the kinematic constraint mechanism of the inner screen box of the chaotic vibrating screen to solve the freedom of motion and POC (position and orientation characteristic) equations of parallel kinematic constraint mechanism of the outer screen frame and hybrid constraint mechanism of the inner screen box. The dynamic simulation of a virtual prototype of the chaotic vibrating screen was carried out in ADAMS software, and MATLAB was used to chaos recognition of the simulation results. It was found that the chaotic exciter moved aperiodically in X-, Y-, and Z-directions when the chaotic exciter motor rotated at uniform speed, and the amplitude, velocity, and acceleration of the outer screen frame of the vibrating screen had characteristics of reciprocating aperiodic and irregular changes. Through the phase trajectories of the eccentric block and inner screen box of the exciter in all directions, it was observed that the motion output of the vibrating screen was a chaotic vibration. Therefore, the present paper can provide an important reference for the design and application of chaotic vibrating screens.

show abstract

Chaotic vibrations of flexible shallow axially symmetric shells

Cited by 15 publications

References 37 publications

SEIR modeling of the COVID-19 and its dynamics

SEIR modeling of the COVID-19 and its dynamics

Visualization of EEG signal entropy in schizophrenia

Design and Dynamic Analysis of a Four‐Degree‐of‐Freedom Chaotic Vibrating Screen

Contact Info

Product

Resources

About