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Dynamic Analysis and Performance Evaluation of Inerter Fractional Nonlinear Quasi-Zero Stiffness Isolator on a Multi-Span Bridge Under Moving Load

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SSRN 2024年

作者： Nguebem, L.H. Dongmo Mba Feulefack, S.C. Ngounou, A.M. Nana Nbendjo, Blaise Romeo Laboratory of Modelling and Simulation in Engineering Biomimetics and Prototypes Faculty of Science University of Yaounde I P.O. Box 812 Yaounde Cameroon

In this paper we propose a new vibration isolator system, which combines the advantagesof a quasi-zero stiffness (QZS) isolator, a damper exhibiting fractional propertiesand an inerter, to reduce the vibrations of a multi-span continuous beam bridge excitedby moving loads. The inerter produces a ﬁctitious mass ampliﬁcation effect toimprove the controller performance and the fractional order takes into account the previousstate of the viscoelastic material. After formulating the dynamics equation usingbeam theory, the amplitude response is determined analytically using the averagingmethod. The results obtained from the analytical study are validated using the directnumerical simulation method (Newton-Leipnik method). By comparing the isolationperformance of the FQZS (fractional quasi-zero stiffness) isolator and the IFQZS (inerterfractional quasi-zero stiffness) isolator, it is shown that the addition of inertancecan signiﬁcantly suppress the tendency of the curve to slope to the right, allowing us tohave a wider isolation frequency range on force transmissibility while improving theeciency of the isolator. One also shows that increasing the fractional parameter contributesto a decrease in the vibration amplitude of the structure, the amplitude of theforce transmitted and the area in which unstable solutions appear. However, beyond acertain value of the fractional parameter, we observe an increase in the latter. In orderto further extend the study, bifurcation diagram, phase portrait, time history and powerspectral density are explored. © 2024, The Authors. All rights reserved.

关键词： Stiffness

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Vibration Control of Two Portal Frames Type Shear Buildings Through Self-Synchronous Dynamics of Two Non-Ideal Sources Indirectly Coupled

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SSRN 2024年

作者： Nanha Djanan, Armand Anthelme Nana Nbendjo, Blaise Romeo Seemann, Wolfgang Laboratory of Modelling and Simulation in Engineering Biomimetics and Prototypes University of Yaounde I PO Box 812 Yaounde Cameroon Karlruhe Institute of Technology Kaiserstraße 10 Karlsruhe76131 Germany

The present paper proposes a new device where it is observed the self-synchronization between two unbalanced DC motors with a limited power supply when they are indirectly coupled. The vibrating system studied consists of two portal frames type shear buildings coupled, carrying each an unbalanced DC motor. The engines are supposed to rotate in the same direction and act on each as external excitation. The dynamics investigations are done with analytical and numerical methods to achieve this purpose. The synchronous solutions are derived and their stability conditions are also explored using the averaging method. The results of this analytical investigation are confirmed later by numerical simulations. The effects of some physical parameters on the self-synchronization of DC motors are presented. The impact of the nonlinear coupling between the floors on the DC motors dynamics is also explored. The Sommerfeld effect appearing in the system is reduced by taking into account the damping coming from the environment and the coupling between the portal frame. It is observed that in-phase synchronization of the non-ideal sources assures low amplitude of vibration in the different floors compared to opposite-phase synchronization. © 2024, The Authors. All rights reserved.

关键词： Floors

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Synchronous Dynamics of Two Dc Motors with Limited Power Supply Indirectly Coupled

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SSRN 2024年

The present paper proposes a new device where it is observed the self-synchronization between two unbalanced DC motors with a limited power supply when they are indirectly coupled. The vibrating system studied consists of two portal frames type shear buildings coupled, carrying each an unbalanced DC motor. The engines are supposed to rotate in the same direction and act on each as external excitation. The dynamics investigations are done with analytical and numerical methods to achieve this purpose. The synchronous solutions are derived and their stability conditions are also explored using the averaging method. The effects of some physical parameters on the self-synchronization of DC motors are presented. The impact of the nonlinear coupling between the floors on the DC motors dynamics is also explored. The Sommerfeld effect appearing in the system is reduced by taking into account the damping coming from the environment and the coupling between the portal frame. © 2024, The Authors. All rights reserved.

关键词： DC motors

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Exact Mathematical Model for the Behavior of a Two-Layer Isotropic Plate with Partial Interaction

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SSRN 2023年

作者： Doumia, Benoît Woafo, Paul Nguyen, Quang Huy Université Européenne de Bretagne - INSA de Rennes LGCGM/Structural Engineering Research Group 20 avenue des Buttes de Coësmes CS 70839 RennesF-35708 Cedex 7 France Laboratory on Modelling and Simulation in Engineering Biomimetics and Prototypes TWAS Research Unit Faculty of Science University of Yaounde I Box 812 Yaounde Cameroon Civil Engineering Department Higher Institute of Technology University of Bangui Box 1450 Central African Republic

This paper analyses the spatial variation of the deflection, and slip at the interface of two-layer composite square plate simply supported under distributed static loading. The Timoshenko model is considered and the equations are solved using the analytical methods and direct numerical simulation with Abaqus software. Two models (two-layer isotropic plate and single-layer isotropic plate) are compared in deflections, and the results obtained show that there is a good agreement between the results of the mathematical calculation and those of the numerical simulation. The geometrical and material parameters are studied and the results show that when the connection stiffness at the interface is zero, the deflection reaches its layered limit and the slip is large. These results affirm that the two-layer plate works like a single-layer plate when its deflection reaches its monolithic limit;it means that there is no slip between two layers at the contact place. © 2023, The Authors. All rights reserved.

关键词： Numerical methods

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On the robustness of the in vivo cyanobacterial circadian clock

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arXiv 2022年

作者： Fouego, Dorota Youmbi de Buyl, Sophie Laboratory of Modelling and Simulation in Engineering Biomimetics and Prototypes TWAS Research Unit Department of Physics Faculty of Science University of Yaoundé I Po. Box 812 Yaoundé Cameroon Applied Physics Research Group Physics Department Vrije Universiteit Brussel Brussels1050 Belgium Interuniversity Institute of Bioinformatics in Brussels Brussels1050 Belgium

We propose a revisited version of the in vivo model of the cyanobacterial circadian clock. Our aim is to address the lack of robustness predicted for the mutant cyanobacteria without transcriptional regulation of the original model. For this, we rely on an in vitro model of the clock describing explicitly the hexameric structure of the core protein of the clock. Our model is able to reproduce oscillatory behavior for the mutant, as observed experimentally, without finely tuned parameters. © 2022, CC BY-NC-SA.

关键词： Clocks

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Dynamics of an Array Mechanical Arms Coupled Each to a Fitzhugh-Nagumo Neuron

Research Square

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Research Square 2021年

作者： Mbeunga, N. Kouami Bonaventure, Nana Woafo, Paul Laboratory of Modelling and Simulation in Engineering Biomimetics and Prototypes Faculty of Science University of Yaounde I PO Box 812 Yaounde Cameroon Department of Physics Higher Teacher Training College University of Bamenda PO Box 39 Bamenda Cameroon

In this work, an array of electromechanical systems driven by an electrical line of Fitzhugh-Nagumo neuron is analyzed. It is shown that a single electromechanical system can display different dynamical behaviors such as single and multiple pulse generation, transient chaos, permanent chaos, and antimonotonicity according to the system parameters. In the case of an array of the electromechanical system constituted of a series of coupled discrete Fitzhugh-Nagumo neuron, the numerical simulation shows that as the action potential flows in the discrete array, each electromechanical system executes a pulse-like motion coming at each resting state as the electrical signal passes the node. The electromechanical system analyzed can be seen as a model for multiperiodic actuation processes or a leg model in a millipede system. Furthermore, this line can also carry an envelope of action potential and can be useful for various kinds of information processing systems. © 2021, CC BY.

关键词： Neurons

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Stability and electronic circuit implementation of Lotka–Volterra model with delay

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International Journal of Electronics Letters 2020年第3期8卷 285-297页

作者： Ngouabo, Ulrich Gael Tekougoum Metioguim, Eugenie Noubissie, Samuel Unité de Recherche de Matière Condensée d‘Electronique et de Traitement du Signal (LAMACETS) Department of Physics University of Dschang Dschang Cameroon Laboratory of Industrial and Systems Engineering Environment (LISEE) IUT/FV Bandjoun University of Dschang Bandjoun Cameroon Laboratory of Modelling and Simulation in Engineering Biomimetics and Prototypes and TWAS Research Unit Faculty of Science University of Yaoundé I Cameroon

In this work, we study a Lotka–Volterra system with delay. We carry out an analytical study from which there emerge three equilibrium points. In the absence of delay, two of these points are unstable whatever the choice of the parameters of the system, and the other one is stable according to the chosen parameters. With delay, and looking only at the point of positive coexistence, we find that it can cause not only instability, oscillations and switching stabilities, but also chaos. In addition, the analytical study revealed the phenomenon of switch stability, thus increasing the zones of instability. Time traces, phase portraits and bifurcation diagram obtained by numerical simulations complement the analytical investigations. Finally, we propose an electronic circuit with delay whose simulation presents the different phenomena observed numerically, thus validating this new electronic circuit with complex dynamics. © 2019 Informa UK Limited, trading as Taylor & Francis Group.

关键词： bifurcation chaos delay electronic circuit filters Lotka–Volterra model stability

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Experimental Assessment of a Smart Sun Tracking System Consumption for the Improvement of a Crystalline Silicon Photovoltaic Module Performance under Variable Weather Conditions

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Applied Solar Energy (English translation of Geliotekhnika) 2019年第6期55卷 385-396页

作者： Hyacinthe Tchakounte Claude Bertin Nzoundja Fapi Kamta, Martin Haman-Djalo Woafo, Paul National School of Agro-industrial Sciences Department of Electrical Energetic and Automatic Engineering University of Ngaoundere Ngaoundere Cameroon IRIMAS Laboratory University of Haute Alsace Mulhouse68200 France Department of Physics Faculty of Science University of Ngaoundere Ngaoundere Cameroon Laboratory of Modelling and Simulation in Engineering Biomimetics and Prototypes Faculty of Science University of Yaounde I Yaounde Cameroon

Abstract: Sun tracking systems are often used to improve the performance of crystalline silicon photovoltaic plants. However, their power consumption still remains a challenge till date. In this paper, a low power consumption sun tracking system has been implemented for driving a crystalline silicon photovoltaic module under variable weather conditions. The experimental results showed that this sun follower consumes less than 1% of the increased energy. Taking into account the tracker consumption, the energy gain can attain up to 25% under the same weather conditions compared to a fixed photovoltaic system. In addition to that, results gotten from data-based simulations are coherent with experimental results. © 2019, Allerton Press, Inc.

关键词： Electric power utilization

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On the dynamics of two multi-span continuous beam bridges model coupled by their close environment

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International Journal of Dynamics and Control 2018年第1期6卷 29-40页

作者： Bouna, H. Sonfack Nana Nbendjo, B.R. Woafo, P. Laboratory of Modelling and Simulation in Engineering Biomimetics and Prototypes Faculty of Science University of Yaoundé I P.O. Box 812 Yaoundé Cameroon

In this paper, we sought to develop a valid theoretical model of two bridges coupled via their dynamic environment modelled as a linear viscoelastic Winkler foundation. Analytical, numerical and experimental study of the dynamic response of the two bridges are explored in the cases where they are submitted to sinusoidal excitation and periodic impulsive force. The effects of the close environment and the distance between the two bridges on the amplitude of vibration of each beam bridge is pointed out. © 2016, Springer-Verlag Berlin Heidelberg.

关键词： Coupled bridges Periodic impulsive force Sinusoidal excitation Vibration reduction Winkler foundation

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Nonlinear dynamics in an optoelectronic feedback delay oscillator with piecewise linear transfer functions from the laser diode and photodiode

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Physical Review E 2020年第4期102卷 042217-042217页

作者： Géraud R. Goune Chengui Kengne Jacques Paul Woafo Yanne K. Chembo Laboratories d'Automatique et Informatique Appliquée (UR-AIA) Department of Electrical Engineering IUT-FV Bandjoun P.O. Box 134 Bandjoun Cameroon Laboratory of Modelling and Simulation in Engineering Biomimetics and Prototypes Department of Physics Faculty of Science P.O. Box 812 Yaoundé Cameroon University of Maryland A. James Clark School of Engineering Department of Electrical and Computer Engineering and Institute for Research in Electronics and Applied Physics (IREAP) 8279 Paint Branch Drive College Park Maryland 20742 USA

We investigate the nonlinear dynamics of a recent architecture of an optoelectronic oscillator, where the emitting laser and the receiving diode are connected in a head-to-tail configuration via an optical fiber delay line. The resulting nonlinear transfer function is a piecewise linear profile, and its interplay with the delay leads to many complex behaviors such as relaxation oscillations and deterministic chaos. This system belongs to a recent class of optoelectronic oscillators where the nonlinearity does not originate from the sinusoidal transfer function of an imbalanced interferometer, and, in particular, it is a simple optoelectronic oscillator configuration that is capable of displaying a chaotic behavior. The results of the analytic study are confirmed by numerical simulations and experimental measurements.

关键词： Control & applications of chaos Chaotic systems

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